Y1 Medicine (c)
What causes local unwinding of DNA and formation of transcription bubble?
TF2H causes local unwinding and formation of transcription bubble (approx. 20 nucleotides long)
What is the rhythm strip, how long do QRS complexes and PR intervals last and what are the axes on an ECG?
Taken from lead II as gives largest signal. QRS - 60-100ms and PR - 120-200ms. 1 large square = 0.2secs (horizontal) and 1mV (vertical)
How, and where is cholesterol taken up?
Taken up in hepatocytes and other cells. Ingested via enterocytes. Stored in fat droplets in sER by pumping esters into leaflets of membrane with monolayer as hydrophobic contents
Why is the foot more stable in dorsiflexion and eversion?
Talus wider anteriorly and medial malleolus shorter than lateral malleolus
What are the types of summation in motor neurons from muscle spindle nerve fibres?
Temporal summation (input from single Ia afferent in high frequency burst to cause AP in motor neuron) and spatial summation (simultaneous EPSPs from mutliple Ia afferents to cause AP in motor neuron)
What is an enthesis and what are the different parts of it?
Tendon-bone attachment at muscle insertion site Dense regular CT --> fibrocartilage --> mineralised/calcified --> bone
What is the function of the muscles in the middle ear?
Tensor tympani and stapedius control how sound transferred across middle ear
What does the knee jerk reflex test?
Tests integrity of femoral nerve and spinal roots L2-L4
What causes clonal expansion?
Th cell recognises antigen and MHC, IL-2 receptor (CD25) accepts IL-2 which causes clonal expansion
What cytokines do Th1 and Th2 cells produce and what do they control?
Th1 - IFN and TNF (cell-mediated/intracellular). Th2 - IL-4, IL-5 and IL-13 (humoral/extracellular)
What cytokines stimulate differentiation into Th1/Th2?
Th1 differentiation - IL-12 and IL-23. Th2 differentiation - IL-4
What types of leprosy, TB and Leishmaniasis are associated with Th1/Th2 cells?
Th1 dominant - tuberculoid leprosy, cutaneous Leishmaniasis and lepromatous TB. Th2 dominant - lepromatous leprosy, visceral Leishmaniasis and miliary TB
What causes type I hypersensitivity?
Th2 response that releases IL-4 that drives IgE production
What are the capillaries found in the anterior pituitary?
Two sets - First set in neck of pituitary stalk and second set in anterior pituitary body, both connected by portal vein
What are the features of the sympathetic nervous system?
Two sympathetic chains (one each side of vertebral column). Divergence - preganglionic fibres branch to postganglionic fibres at different levels, convergence - postganglionic neuron receives info from many preganglionic fibres
What do local anaesthetics do?
Bind to open Na+ VGCs and allows inactivation and prevent from returning to resting state, preventing reopening and subsequent action potentials
What does the trochlear nerve carry and what does trochlear nerve palsy cause?
Carries motor fibres to superior oblique. Palsy causes diplopia when looking down and head tilt away
What impacts pattern of fluid flowing through a tube and what are the types of flow
Depends on physical properties of liquid and velocity. Flow can be laminar (smooth) or turbulent
What does success of nerve repair depend on?
Depends on severity of initial injury (both what has been damaged and how much has been damaged) and extent of 2y damage
What is gluconeogenesis and when does it occur?
Formation of glucose in the liver when liver glucose is depleted. Occurs under starvation and during intense anaerobic exercise
What forms the TMJ and what separates it?
Formed by articulation between condyle of mandible and mandibular fossa of temporal bone. TMJ separated by articular disc
What structures form the lacrimal apparatus, what is the function of lacrimal glands and what stimulates them?
Formed by lacrimal gland and associated ducts. Lacrimal glands secrete tears and are stimulated by parasympathetic division of CN VII
What bones form the pelvic girdle, what joint connects ilium to sacrum and what connects the hemi-pelvis anteriorly?
Formed by pubis, ilium and ischium. Iliosacral joint connect ilium to sacrum and pelvic symphysis connects hemi-pelvis anteriorly
What are the structures that form the nasal septum and what are the features of the ethmoid bone?
Formed by septal cartilage, perpendicular plate of ethmoid and vomer. Ethmoid bone has superior/middle concha and crista galli (superior projection)
Where and how is CSF formed?
Formed in choroid plexus in ventricles. Allow water and small ions to pass out of capillaries to form CSF that bathes brain in fluid
What is the role of vitamin A?
Forms retinoic acid which is important in imprinting cells to home to the gut mucosa from PPs. Gut dendritic cells have retinal dehydrogenases that produce retinoic acid
What does stomach mucosa form when non-distended, what are the mucous secreting cells, what do other cells secrete and what are the layers of the muscularis propria?
Forms rugae when non-distended. Mucous secreting cells are mucous neck cells and columnar surface cells. Other cells secrete HCL and IF (parietal cells) and pepsinogen (chief cells). Muscularis propria has 3 layers (inner oblique, middle circular and outer longitudinal)
Where is the basal ganglia and what does it contain?
Found around thalamus and contains nuclei involved in motor coordination
Where in the meninges are blood vessels?
In dura and arachnoid. Veins in meningeal dura and crossing dura-aracnhoid interface with many blood vessels in subarachnoid space
In what population are micronutrients most important and why?
Most important in paediatric population as important for normal development and growth due to increased energy demand
What are capsids and what are the shapes?
Protein coats surrounding genome for protection from host and to deliver into host. Can be spherical, icosahedral or complex
What is temporal and spacial summation?
Temporal summation - impulses received from same synapse in rapid succession. Spacial summation - impulses received from different synapses and add
Describe the structure and function of skeletal muscle
Striated, voluntary muscle with multinucleate cells with peripherally located nuclei. For locomotion, breathing and posture
What are the causes of stroke, what are the types of cerebral aneurysms, what is their danger and where are they most likely to form?
Stroke causes - atherosclerosis, aneurysm, age, HT, trauma, alcohol. Cerebral aneurysms can be saccular, berry or fusiform. Danger comes from when they burst and most likely to form at divisions where blood flow is turbulent
What is reciprocal inhibition?
Tendon tap that activates extensor reflex also inhibits antagonistic flexor muscle by action of inhibitory interneuron
What is afterload and compliance and the link between the two?
Afterload is impedance of the aorta to blood flow. Compliance is the degree of stretch. A high compliance causes a low afterload so heart has to do less work to generate a given CO
What can cause a drop of pelvis on unsupported side and what is Trendelenburg's sign?
Caused by weak hip abductors, #NOF/greater trochanter or dislocated femoral head
How can aneurysms be caused, where do they occur and what are the major risk factors?
Caused by weakness of arterial wall which increases lumen size which decreases resistance of wall to pressure. Occur before branches as this causes turbulent blood flow. Major risk factors include hypertension and artery disease
What is type V/McArdle's disease?
Autosomal recessive disease causing deficiency in glycogen phosphorylase in muscle tissue so struggle with exercise at first. After intense exercise, CK and myoglobin levels increased in urine/blood due to muscle damage
What is the course of the vestibulocochlear nerve and what does it provide?
Emerges from pons and enters internal acoustic meatus to provide special sensory fibres for hearing and balance
How is FA metabolism controlled?
FA metabolism controlled by regulation of FA transport via CPT-I. CPT-I inhibited by malonyl CoA (made when glucose is abundant) and stimulated by glucagon via cAMP. Can also be controlled transcriptionally with levels rising in extended fasting and diabetes
What CNs are in the parasympathetic nervous system and what is it's other name?
Craniosacral - CN III, VII, IX and X
How can common peroneal nerve be damaged and what does this result in?
Damaged by head of fibula fractures. Causes foot drop due to paralysis of dorsiflexors and sensory loss to foot dorsum
How can CN XI be damaged and what does this cause?
Damaged by lymph node surgery to cause weak shoulder shrugging, trapezius atrophy and shoulder drooping. Normal passive shoulder movements but gives weakness in turning head to opposite side against resistance
Describe the venous drainage of the gut, pelvis and lower limb and what can portal hypertension cause?
Gut drains into hepatic portal system (stomach and spleen into splenic vein, midgut into SMV and hindgut into IMV). Gonadal, renal and internal/external iliac veins all drain into IVC. Portal hypertension can cause oesophageal varices
What does hyaluronic acid interact with in the synovial fluid and what does this do?
HA interacts with albumin to form glycoprotein gel. This entangled gel acts as a shock absorber and resits deformation
What are the major hip flexors, what innervates them, what other movements do they do and what is the role of psoas minor?
Hip flexors (innervated by femoral nerve) - iliopsoas (iliacus and psoas major), sartorius (abducts and laterally rotates) and pectineus (adducts and medially rotates). Psoas minor stabilises psoas major
What type of joint is the hip joint and what does head of femur articulate with?
Hip joint is ball and socket synovial joint and head of femur articulates with the pelvic acetabulum
What is autosomal dominant inheritance?
If parent affected, child has 50% chance but can occur de novo. Affects and transmitted by both sexes. Sufferers are heterozygous but has variable penetrance (may be asymptomatic) and anticipation
What is autosomal recessive inheritance?
If parents carriers, child has 25% chance. Affects and transmitted by both sexes. Sufferers homozygous or compound heterozygotes
Why and how do bacteria invade non-phagocytic cells?
Invade by zipper (high-affinity binding to receptors causes uptake) or trigger (inject virulence factors to activate uptake). Helps to evade immune system and rich in nutrients
How are keratin pearls formed?
Invading squamous cells retain ability to produce keratin which is trapped in tumour
What nerves do they join to, when are they activated and when does action potential frequency increase?
Join to CN IX or X and are activated when stretched. Action potential frequency increases during systole and reduces during diastole
What is different about the space between joints in children on XR and why?
Joint space appears larger due to epiphyseal growth plates made from hyaline cartilage that don't show on XR
How are Na and Cl transported in the thick part of the ascending loop of Henle?
K pumped from into lumen using ROMK which makes outside have positive potential and passively draws Na, Cl and K back into cell using NKCC2 and then into interstitium by Na/K ATPase
What are loading and maintenance doses?
Loading - large dose gets to therapeutic range quicker. Maintenance - smaller doses to maintain in therapeutic range
How do you calculate local flow and what does a high BP ensure from this?
Local flow = pressure / local resistance. Therefore, a high BP ensures that any changes in local resistance (eg. vasodilation) are effective in changing local flow
What symptoms and signs does damage to medulla cause?
Loss of pain sensation, loss of gag reflex, dysphagia, hoarseness of voice, tachycardia, tongue muscle atrophy
What are the types of fungi and what is found in the cell wall?
Mould (grows as hyphae filaments to form mycelium mesh, reproducing by forming spores) and yeasts (grow as single cells and divide by budding). Cell wall made from chitin
What is the function of the intrinsic laryngeal muscles and what are their innervation?
Move laryngeal components to alter length and tension of vocal folds and size/shape of rima glottidis. Cricothyroid innervated by superior laryngeal and all others innervated by recurrent laryngeal
What determines movement of water and by what process?
Movement by osmosis (from low to high solute conc across partially permeable membrane). Determined by osmotic pressure (pressure required to oppose water uptake) and hydrostatic pressure (created by pumping action of heart)
What are the functions of skeletal muscle?
Movement, maintaining posture, stabilising joints and thermogenesis
What is the function of ADH?
Moves aquaporins into membrane of collecting duct to increase H2O reabsorption, increases permeability of collecting duct to urea and increases Na reabsorption by NKCC2 in thick ascending loop of Henle
What are the histological features of the gut wall?
Mucosa (made from epithelium, lamina propria and muscularis mucosa), submucosa (made from thick layer of fibrocollagenous tissue for shock absorption and carries vessels and nerves), muscularis propria (inner circular layer and outer longitudinal layer) and adventitia/serosa (adventitia if retroperitoneal or serosa if peritoneal)
How do you name malignant tumours?
Name of origin + morphological charater + -sarcoma/-carcinoma. Epithelia form carcinomas, mesenchymal cells form sarcomas
Where is the 3rd ventricle found and what does it contain?
Narrow vertical slit in forebrain full of CSF that runs antero-posteriorly along midline above midbrain lying between left and right thalamus
What is the refractory period in ventricular cells and what is its function?
Period where ion channels are inactivated so muscle unresponsive to further APs so individual contractions can't fuse
What NTs are for fast and modulator neurotransmission?
Fast - ACH, glutamate, GABA, glycine and 5-HT Slow - ACH, glutamate, noradrenaline, 5-HT, dopamine
How are fatty acids stored and how are triglycerides metabolised?
Fatty acids stored as triglycerides in fat droplets that can be hydrolysed using lipase to create glycerol and fatty acid. Secreted to blood and bound to serum albumen that is taken up by cell and oxidised in mitochondria for ATP generation
What are atheromas and why do they have a great impact?
Fatty deposits on inside of artery. Have a large impact because a small decrease in lumen size has a large impact on flow so can cause tissue hypoxia
What happens to GABA, biogenic amines and glutamate after use in synaptic cleft?
GABA reuptaken into presynaptic terminal and astrocytes by GAT. Biogenic amins reuptaken into presynaptic terminal. Glutamate reuptaken by Na/K-dependent glutamate transporter
How is GFR regulated and what regulates this?
GFR regulated by constriction of afferent/efferent arterioles. GFR decreases when afferent constricts and efferent dilates and GFR increases when efferent constricts and afferent dilates. Controlled by JG apparatus
How is glucose moved in enterocytes?
Glucose moved from lumen by Na+ driven symport. On basal membrane, Glut2 allows facilitated diffusion of glucose and Na+/K+ pump pumps Na+ into portal vein to maintain gradient
What are fluoroquinolones?
Group of antibiotics that act on topoisomerases (prevent supercoiling of DNA) so cause DNA to break. Examples - gemifloxacin, levofloxacin, ciprofloxacin, nalidixic acid. Act on Gram +ve/-ve aerobic bacteria
How can cancer cells evade apoptosis?
Production of anti-apoptotic proteins or reduction of pro-apoptotic proteins
What is resting tone, how can certain drugs affect this and what vascular beds aren't subject to resting tone?
Tonically active regulation of blood distribution. Alpha blockers (prazosin) block resting tone so unable to increase vasoconstrictor tone in leg muscles so blood pools and BP drops. Brain and heart aren't subject
What is BCL-2 and how can a mutation cause cancer?
t14:18 moves highly active IgH heavy chain promotor to BCL-2 (anti-apoptotic protein) gene so cell evades apoptosis. Causes some B-cell lymphomas
How is adrenaline made and degraded?
Tyrosine --> L-DOPA --> dopamine --> noradrenaline --> adrenaline (in adrenal medulla). Degraded by monoamine oxidase
What can be made from tyrosine, tryptophan, ariginine, histidine, glycin, glutamate and aspartate?
Tyrosine --> noradrenaline, dopamine, melanin, adrenaline and thyroxine Tryptophhan --> serotonin, melatonin Arginine --> NO Histidine --> histamine Glycine, glutamate and aspartate --> act directly as NTs
What are ulcerative collitis and Crohn's disease?
UC is superficial and affects colon and can cause backwash ileitis. CD is transmural, mainly in terminal ileum but affects mouth to anus and can cause fissures and fistulae
What is the contents of CSF and how is it absorbed?
Very little protein (0.3-1.0%) and no cells so not pH buffered and 60% of [plasma glucose] Absorbed by arachnoid granulations which penetrate dura to join venous blood in SSS
Where is woven bone found?
Very small proportion of woven bone in adults. Found in immature childhood and healing fractures but can also be pathological (eg. Paget's disease of the bone)
What is the effect of weak and high pressure on slowly adapting receptors?
Weak pressure - bends axon slightly so small receptor potential which triggers low frequency APs in nerve fibre High pressure - bends axon lots so large receptor potential which triggers high frequency APs in nerve fibre
What is a therapeutic target, what is different about neurological disease and what are synaptic targets?
Well defined entity such as receptors or enzymes Neuro disease often has high level complexity and involves several regions Targets - uptake, metabolism and receptors
When can transcription start?
When C terminal domain of RNA polymerase is phosphorylated
What is AIDS?
When CD4 <200 cells/uL. Immunodeficiency causes susceptibility to opportunistic infections
What are ligands gated ion channels and 3 examples?
When ligand binds, ion channel opens and allows movement of ions. NACHRs for Na+ diffusion, NDMA/glutamate receptors for Ca2+ diffusion and GABA receptors for Cl- diffusion
What is metaplasia, where does it normally occur and give an example?
When one type of cell is replaced by another type. Normally occurs in epithelial transitional zones (eg. cervix and uterus). Gastrointestinal reflux disease (GIRD) causes replacement of oesophegeal squamous epithelium with mucus-secreting columnar epithelia from stomach
What is cell differentiation and what affects it?
Where less specialised cell become specialised. Transcription factors turn on at different times and act on gene expression and change differentiation
What is cAMP?
cAMP is a 2nd messenger molecule activated by adenylyl cyclase and degraded by phosphodiesterase. Stimulates cAMP-dependent protein kinase A (PKA)
How can drugs block cytokines?
mAbs (infliximab anti-TNF) and soluble receptors (TNF receptor enteracept)
Describe characteristics of benign tumours
Slow growing, localised, low mitotic rate, well differentiated
How are small and protein NTs recycled?
Small - transported back into neuron and recycled. Protein - degraded by non-specific proteases
What are cytokines?
Small proteins or glycoproteins. Can be interleukins, interferon or tissue necrosis factor (TNF)
How is the steep part of the O2/Hb dissociation curve useful?
Steep part useful as small changes in pO2 in tissues cause large changes in O2 unloading
What stimulates the macula densa and what does this cause?
Stimulated by low Na in DCT which causes release of local hormones that cause local smooth muscle relaxation to increase GFR and also cause JG cells to release renin
What are the steps of translation?
Synthesis then removal of incorrect AAs at editing site
What does fatty acid breakdown produce and what does this allow?
"Broken down to form acetyl CoA and NADH and FADH that allow for ATP synthesis in ETC. ATP allows pyruvate --> oxaloacetate Levels of acetyl CoA regulate pyruvate --> oxaloacetate by activating pyruvate carboxylase
What is a receptive field and what does progressive loss of fibres lead to?
Area of skin innervated by a single nerve fibre. Progressive loss of fibres leads to progressive worsening ability to localise stimuli as there is less and less overlap between receptive fields
Describe the pathway of sympathetic visceral motor neurons from the thoracic spinal cord
Arise from intermediolateral horn part of ventral horn. Pass through communicating ramus to end on postganglionic neurons in sympathetic ganglia
How can spinal nerves be damaged by vertebra and what does it cause?
Can be damaged when they leave spinal cord in intervertebral foramina and causes paresthesia/anaesthesia referred to relevant dermatome
What are TLRs and what do they do?
Can be dimers or monomers on plasma membrane or endosomes and activate MAPk or NFkB pathways for cytokine production
What is the effect of plasma proteins on fluid movement and what can disturb fluid balance?
Can't leave capillary so exert oncotic pressure that draws fluid into capillary. Altering HP or OP can disturb fluid balance
Define cancer, malignant, metastasis, benign, tumour and neoplastic cells
Cancer - abnormal growth of cells that mutliply uncontrollably and can metastasise. Malignant - tumours that invade nearby tissues and metastasise. Metastasis - spread of cancer cells from 1y site to surrounding tissues/organs. Benign - grown locally and don't invade. Tumour - abnormal mass of tissue that grows uncontrollably. Neoplastic - lost control of normal processes and irreversible
What cells are found in cancer sites?
Cancer stem cells, fibroblasts, pericytes, immune inflammatory cells and microenvironment of parenchyma (functional tissue) and stroma (support tissue)
Why can neoplasms be differentiated from healthy brain tissue on MRI?
Capillary endothelial cells lack tight junctions so allows relative hydration of neoplasm
What other factors determine ability of a drug to affect target?
Capillary structure, drug structure, blood flow through tissue and presence of non-active binding sites
What are the sources of acid in the body?
Carbonic acid (aerobic resp), lactic acid (anaerobic resp), sulfuric acid (metabolism of sulfur-containing Aas), ketone bodies (incomplete oxidation of fatty acids) and phosphoric acid (hydrolysis of nucleic acids)
How is stomach acid formed?
Carbonic anhydrase combines CO2 and H2O to form carbonic acid --> carbonic acid dissociates to form HCO3 and H+ --> HCO3 pumped out of basolateral membrane in exchange for Cl --> Cl pumped out of apical membrane via CFTR --> H+/K ATPase pumps out H+ --> H+ combines with Cl to form HCL
What are MRI contraindications?
Cardiac pacemaker, aneurysm clip, metallic foreign body, cochlear implants, neurostimulator, early pregnancy
Where are carotid arteries and jugular veins found (superficial or deep) and how does the head/neck receive sympathetic input?
Carotid arteries deep and jugular veins superficial. Cervical ganglia receive presynaptic sympathetic fibres via superior thoracic nerves and send fibres to cervical spinal nerves, thoracic, head and neck viscera
How are drugs carried around the body and what does this determine?
Carried whilst bound to plasma proteins (albumin). Bound drugs can't bind to receptors so are inert, can't diffuse, be metabolised or excreted
What does abducent nerve carry and what does abducent nerve palsy cause?
Carries motor fibres to lateral rectus so palsy causes inability to abduct eye
What causes trigger finger?
Caused when tendons of FDS or FDP enlarge proximally to the tendon sheath so the tendon is unable to move into the sheath. Causes a popping sound when passively extended as tendon moves back into tendon sheath
What is water intoxication, what can it cause and how is ecstasy linked?
Caused when too much water drunk too fast or complete blockage of urine production that causes dilution of body fluids. Causes decreased ECF [Na] --> osmotic shift of water into cells --> cell swells and bursts. Ecstasy stimulates ADH release so can cause hyponatremia
What does damage to ascending sympathetic trunk cause and what are signs of this?
Causes Horner syndrome Signs - miosis, anhydrosis, partial ptosis, vasodilation
What does a peripheral nerve injury cause?
Causes areflexia, anaesthesia, paralysis and atrophy
What is the auditory startle reflex?
Causes ducking down (protects back of neck) and blinking
What does damage to facial nerve cause, where are UMN and LMN of facial nerve and what is the motor supply to the upper and lower halves of the face?
Causes flat facial expression. UMN of facial nerve in motor cortex and synapses with LMN in brainstem. Upper half of face has bilateral UMN input from cerebrum and lower half of face has input from contralateral side of cortex
How is pyruvate dehydrogenase complex controlled and what activates pyruvate carboxylase?
Controlled allosterically by acetyl CoA and NADH levels (both inhibit PDC and push to gluconeogenesis). Pyruvate carboxylase activated by acetyl CoA
What are the zones found in the epiphyseal growth plates?
Contains 4 zones. Resting cartilage (contains resting chondrocytes that will enter cell cycle and proliferate), proliferating chondrocytes, chondrocyte hypertrophy (pre-apoptotic and contain glycogen, fat droplets and alkaline phosphatase) and calcified cartilage
Describe beta-D-glucose
C1 OH group above ring as more stable as OH groups spread more evenly so less reactive. In solution, mix of two cyclic structures and straight chain
What are the nerve roots of cervical plexus, where do cutaneous branches emerge, what is the pathway of the phrenic nerve and what is the ansa cervicalis?
C1-C4 roots. Cutaneous branches emerge around middle of posterior SCM border. Phrenic nerve descends down obliquely with IJV across anterior scalene and passes into thorax. Ansa cervicalis (C1-C3) gives motor innervation to infrahyoid muscles
What are the spinal nerve roots of the brachial plexus and what are the terminal branches?
C5-T1. Terminal branches are musculocutaneous (C5-C7), axillary (C5-C6), radial (C5-T1), median (C5-T1) and ulnar (C8-T1) nerves. Mnemonic - MARMU and 3 musketeers assassinated 5 rats, 5 mice and 2 unicorns
What is the carbonic acid buffer system?
CO2 + H2O <--> H2CO3 <--> H+ + HCO3- Can buffer any source (lactic acid, salicylic acid etc.) other than retained CO2
What are the main routes of movement across a capillary endothelial cell and with what substance does each occur?
Diffusion (small lipophilic molecules), through intracellular clefts (paracellular transport) or fenestrations (both hydrophilic substances)or via vesicles (large substances)
What is used for HCV treatment?
Direct acting antivirals (DAAs). NS3 protease inhibitors prevent polyprotein cleavage, NS5A inhibitors block replication complex formation and assembly, NS5B (sofosbuvir) stops viral RNA synthesis
How do tendons of FDS and FDP enter and run through the hand?
FDS and FDP tendons enter common flexor sheeth deep to flexor retinaculum. In the central compartment they split into their digital synovial sheaths that are held in place by fibrous digital tendon sheath
What is the role of FDS, FDP and flexor pollicis longus in the fingers?
FDS flexes the MCP and PIP joints, FDP flexes the MCP, PIP and DIP joints and flexor pollicis longus flexes the MCP and IP joint of the thumb
What symptoms and signs does damage to pons cause?
Facial anaesthesia, weak mastication, medial eye deviation, facial muscle paralysis, loss of taste, dry mouth, vertigo and loss of hearing
What are the facial bones?
Facial bones - zygomatic, nasal, lacrimal, maxilla, mandible, inferior concha, vomer and palatine
What are facilitated and active transport in transporters?
Facilitated - solute binds to randomly exposed site and causes conformational change, exposing solute to other side. Active - solute binding induces ATP binding and conformational change exposes low affinity binding site to EC space so dependent on ATP
What is type VI/Her's disease and how is it treated?
Deficiency in glycogen phosphorylase in liver tissue so unable to maintain short-term fasting blood glucose. Treatment is regular, frequent feeding
What causes dehydration, what does this cause, what disease state causes excess urine production and what groups of people are prone to dehydration?
Dehydration caused when fluid intake is insufficient to cover output. Causes weight loss, fever and confusion. Excess urine production occurs in diabetes and very young (underdeveloped kidney) and elderly (decline of kidney function) are prone to dehydration
What are deletion, duplication, inversion, translocation and Robertsonian translocation mutations?
Deletion - removal of nucleotides, duplication - nucleotides repeated, inversion - section of chromosome reversed, translocation - portions of chromosome are exchanged, Robertsonian translocation - part of chromosome attached to another
What is muscle fatigue and how do monosynaptic reflexes control this?
Despite steady drive from brain via descending pathways, amount of contraction per muscle AP decreases the longer the muscle is contracting Monosynaptic reflexes act as -ve feedback control to maintain constant muscle length despite fatigue
How do renal artery stenosis or atheromas impact the RAAS?
Decreases renal blood flow and GFR so increases [Na] in PCT which decreases [Na] in DCT, stimulating RAAS and causing chronically raised BP and excess aldosterone to cause excess total body water
Describe the venous drainage of the upper limb
Deep (same name as artery, 2 veins for each artery) and superficial veins (basilic (medial) and cephalic (lateral) veins). Superficial veins drain into axillary artery. Median cubital vein across cubital fosssa connects superficial veins and main vein for venepuncture
Describe the venous drainage of the lower limb
Deep (take name of artery and run within fascia) and superficial (small and great saphenous and run outside fascia) veins. Small saphenous drains into popliteal vein and great saphenous drains into femoral vein
What is profunda femoris, what does it supply and what arteries arise from it (and what do they supply)?
Deep artery that branches from femoral that supplies thigh muscles. Medial (posterior) and lateral (anterior) circumflex arteries that supply the head and neck of femur
Where is the thalamus found and what does it do?
Deep in brain either side of 3rd ventricle and receives input from all areas of nervous system
What is the falciform ligament (and what is at the inferior border), lesser omentum and lesser sac?
Falciform ligament connects liver to anterior abdominal wall and has ligamentum teres inferiorly. Lesser omentum is between the lesser curvature of the stomach and the liver and the lesser sac is behind the stomach
Describe the proton pump in the stomach
Found on apical membrane of parietal cells and is dependent on ATP. Is electroneutral so exchanges H+ for K+
What are the functions of the basal ganglia?
Initiation and maintenance of motor actions but doesn't directly regulate execution like cerebellum Involved with 'brake theory' (putting brake on certain movements to allow standing still or movement)
What is the function of y motor neurons and what signs can defects cause?
Innervate muscle spindle and stimulate intrafusal fibre contraction to 'prestretch' spindle and increase response of Ia afferents to stretch. Hyperactive y motor neurons can cause hyperreflexia and spasticity
What nerves innervate diaphragm and where do vena cava, oesophagus and the aorta pass through the diaphragm?
Innervated by C3,4 and 5. Vena cava - T8, oesophagus - T10 and aorta - T12 (aortic hiatus)
How is skeletal muscle innervated?
Innervated by motor neurons with cell body in ventral horn. Axons enter muscle and each axon branches to contact several muscle fibres One muscle fibre has one NMJ
What are arthropods?
Insects and arachnids that can be vectors and can produce poisonous venoms
What are ketone bodies, give examples of, what are they produced from and where?
Ketone bodies are soluble fuels that can be used instead of glucose. Examples are acetoacetate, hydroxybutryric acid and acetone. Produced from acetyl CoA only in liver mitochondria
Give an example of how a lack of anti-inflammatory cytokines can cause disease
Lack of IL-10 can cause intestinal inflammation driven by gut bacteria
What causes JVP?
Lack of valve between vena cava and RA so some backflow of blood
How can G. -ve bacteria be differentiated?
Lactose fermenter test
Describe the structure of the left and right ribs
Left lung - two lobes (divided by oblique fissure) and lingula. Right lung - 3 lobes (horizontal fissure superior and oblique fissure inferior)
What side of the retina sees the right visual field, what does the optic chiasm allow, what is the overall effect of this and where does the optic tract lead to?
Left side of retina sees right visual field. Optic chiasm allows decussation of medial retinal fibres so left visual field from both eye goes to right brain and vice versa. Optic tract leads to lateral geniculate nucleus which leads to optic radiation then visual cortex
What is wobble?
Leniency in 3rd base of anticodon so fewer tRNAs required. Unconventional base pairing can occur
What is the appearance of subdural haematoma on CT?
Lens-shaped but tracks along inside of skull
What are pyrimidine dimers and how are they repaired?
Lesion formed from a covalent bond between C and T from ionising radiation. DNA helicase removes faulty section and gap filled by DNA polymerase and ligase
What are the effects of lesions to brainstem on ventilation?
Lesions below medulla cause cessation of ventilation Lesions at low pons spare apneustic centre and cause apneustic breathing (prolonged inspiration and inadequate expiration)
How do rods respond to light?
Light changes shape of rhodopsin which reduces [cGMP] which closes Na channel in outer segment so cell hyperpolarises to stop glutamate release
What needs to be considered in abnormal skeletal XRs?
Look for changes in shape, size and orientation of bones/joints, breaks in the bone, extra bone (calcification), loss of bone and foreign objects
How do loop and thiazide diuretics work and what is an acid-base disturbance caused by loop diuretics?
Loop diuretics inhibit NKCC2 in ascending limb so cann cause hypokalemic metabolic alkalosis. Thiazide diuretics inhibit Na-Cl cotransporter in DCT but also vasodilate to reduce SVR.
Describe the structure of smooth muscle and the types of attachments?
Loose lattice of thick and thin filaments obliquely across muscle. Intermediate filaments assist in transmission of force and dense bodies that serve as attachments for thick and thin filaments
What are the functions of the pericardium?
Lubrication, limiting dilation, protecting from infection and fixes heart
How can lungs collapse?
Lungs collapse due to damage to pleura, allowing air to enter intrapleural space due to pressure difference and making intrapleural pressure = atmospheric pressure so increased pressure around lungs causes collapse
What is the path of lymphatics and what drains each part of body?
Lymphatic plexi --> lymphatic capillaries --> lymphatic collecting vessels --> lymph nodes --> lymph trunk --> lymph duct --> venous circulation. Upper right drains into right lymphatic duct, rest of body into thoracic duct
What are M cells, how are T and B cells activated and how do they migrate to lamina propria?
M cells in PPs are epithelial cells that transport gut antigens across the epithelium into the body. T and B cells are activated by gut antigens in PP and migrate to lamina prpria using afferent lymph and bloodstream
What are selective muscarinic antagonists?
M1 - pirenzepine/telezepine (reduce gastric acid secretions). M2 - gallamine (causes tachycardia). M3 - darifenacin/solifenacin (treat urinary incontinence)
What is MAP and how is pulse pressure smoothed?
MAP = diastolic + (1/3 x pulse pressure). Pulse pressure smoothed due to compliance of arterioles from elastin
What is the mitochondria and why are diseases associated with them?
Main centre for production of ATP in a cell. Diseases inherited from mother and affected highly active tissues (eg. muscles and nerves). Damage from free radicals may cause ageing
What is rectus abdominis muscle, what is it used for, where does it run from and to and what features are seen?
Main muscle that makes up anterior part of abdominal wall used for trunk flexion. Runs from pubic symphysis to xiphoid process. Linea alba down midline and tendinous intersections that run transversely
What are the main sources of short and long term energy buffering and what is the ideal energy store?
Main source of short term buffering is carbohydrates and long term is lipids/ketone bodies. Lipids in the form of TAGs are the ideal energy store as they have a high energy density
What are the functions of astrocytes?
Maintain local pH and glucose, remove excess NTs/metabolites, buffer extracellular K, secrete growth factors, secrete cytokines in disease processes and form astrocytic scar after CNS injury
What organs are in the male and female pelvic cavities?
Male - ureter, urethra, prostate, rectum. Female - rectum, ureter, ovaries, vagina, bladder
What are the causes of TMJ pain?
Myofascial pain (increased muscle tension), internal derangements (problem with articular disc) or degenerative joint disease (arthritic changes)
What is the origin of the hamstrings, where do they attach, what movement do they do and what nerve innervates them?
Originate from ischial tuberosity and attach to tibia so flex the knee. Innervated by tibial branch of sciatic nerve
What are the muscle fibres in the lips, what do they do, what innervates them, what muscle makes up the cheek and what innervates muscles of facial expression?
Orricularis oris that acts as a sphincter muscle that encircles the mouth and is innervated by facial nerve. Buccinator muscle makes up cheek and is also innervated by facial nerve as is a muscle of facial expression
What cytokines cause chronic inflammation?
Overproduction of Th1 cytokines can cause Crohn's etc.
What are oxidoreductases, tranferases, hydrolases, lyases, isomerases and ligases and an example of each?
Oxidoreductases for reduction and oxidation reactions (alcohol dehydrogenase), transferases for transfer of atoms (alanine transaminase), hydrolases for hydrolysis (peptidase), lyases for addition/removal of group to double bond without hydrolysis or oxidation (pyruvate decarboxylase), isomerases for rearrangement of atoms to form isomers (maleate isomerase) and ligases for bonding of molecules (pyruvate carboxylase)
What is Laplace's law, what is surfactant and what type of cell is it released by?
P = 2T/R. The smaller the radius of a bubble, the greater the pressure required to keep it inflated. Surfactant is secreted by type II pneumocytes and decreases the surface tension in the alveoli
What does TB meningitis look like on MRI?
Severe inflammation and thickening of meninges around basal cisterns
What are non-coding RNAs?
Small sections of RNA that can bind to mRNA and prevent transcription
What is the function of the rER?
Synthesises proteins and contains ribosomes. Glycosylation of proteins protects from degradation
Describe the mucosal phase of protein digestion
Trypsinogen converted to trypsin by enterokinase. Trypsin activates chymotrypsinogen and procarboxypeptidase. AAs enter enterocytes by Na-linked 2y active transport
What is Rb and how can it cause cancer?
Tumour suppressor and inhibits cell cycle by inhibiting S phase gene expression. When not phosphorylated, binds to E2F which can't bind to DNA so blocks transcription. If Rb mutated/not present, E2F free to bind to DNA and promote transciption
What are the parts of a blood vessel?
Tunica adventitia (connective tissue, vasa vasorum and autonomics), tunica media (contains collagen, muscle fibres and elastin) and tunica intima (1 cell thick simple squamous endothelium)
What are the stages of drug metabolism in the liver?
Phase I - modification (hydroxylation by CYP450) Phase II - conjugation (addition of glutathione) Phase III - further modification/excretion
What are the phases of clinical trials?
Phase I - small group of healthy volunteers, tests tolerability, phase II - tests efficacy on small patient groups, phase III - large patient groups to identify optimum dose and method of administration, phase IV - after licensing to check safety and efficacy
How are phenylalanine and tyrosine metabolised?
Phenylalanine --> tyrosine --> NH3 + hydroxyphenylpyruvate --> fumarate --> glucose and hydroxyphenylpyruvate --> acetoacetate
What energy stores are used in exercise, what does exercise intensity affect and what does AMP act as?
Phosphocreatine > muscle glycogen > blood glucose/blood FAs Exercise intensity greatly decreases [ATP] and increases [ADP] and [AMP] AMP acts as a metabolic signal to increase glucose uptake in short term and FA oxidation in long term
What muscles are used during late stance phase?
Plantarflexors active at toe off to power forward thrust. Hip flexors and knee extensors start to prepare to lift leg
What is elastin and what disease can it cause?
Polymer of fibrillin and tropoelastin. Forms elastic fibres. Can cause Marfan syndrome in blood vessels, leading to rupture
What is glycogen?
Polysaccharide of glucose that stores energy in liver and muscles. Glycogenin enzyme catalyses initial synthesis and starts polymerisation. Broken down by glycogen phosphorylase. Insulin secretion from pancreas stimulates hepatocyte glycogen synthase
Where is a pool of GLUT4 found and what causes recruitment of GLUT4 to the membrane?
Pool of GLUT4 found in vesicles. Recruitment to cell membrane stimulated by insulin action and exercise
Describe characteristics of malignant tumours
Poorly differentiated, fast growing, invade and metastasise by lymph or blood and high mitotic rate
What drugs are used in HF and in patients with preserved/midrange EF and reduced EF?
Positive inotropic drugs, vasodilators and drugs used for chronic failure. Preserved/midrange EF - diuretic used in congested patients. Reduced EF - ACEi and beta blocker
What does tumour growth rate depend on?
Proportion of cells in proliferative pool, doubling time, rate of tumour shed/loss and extent of differentiation
How can glaucoma be treated pharmacologically?
Prostaglandin analogs - increase outflow through canal of Schlemm Beta-adrenergic antagonists decrease production Alpha2-adrenergic agonists decrease production and increase outflow Parasympathomimetic agonists work by contraction of ciliary muscle to open canal Carbonic anhydrase inhibitors reduce secretion
What is the function of the blink reflex and what are the inputs/outputs?
Protects eyes from foreign bodies. Input is sensory nerve endings in cornea or conjunctiva (branches of V1) and output is motor fibres in CN VII to orbicularis oculi which closes eyelids
What does aqueous humour protect against and how are cataracts caused?
Protects lens and inner cornea against free radical damage as it contains antioxidants. If [antioxidant] reduces or too much UV absorbed then lens can gradually become opaque to cause cataracts
What are parasites and protozoa?
Protozoa and Helminths. Protozoa are unicellular eukaryotes that live in aqueous environment and are classified by means of locomotion
Explain the retinoblastoma protein
RB1 (tumor suppressor) protein prevents G1 as inhibits E2F. E2F needs to be phosphorylated by cyclin for cell cycle progression, but activated CDK2 phosphorylates/inactivates RB1 so releases from E2F protein which can activate S entry by increasing cyclin expression. RB1 mutation causes no functional RB protein so E2F free to drive cell cycle
What happens to ACH after binding to NMJ receptor and why is this important?
Released from receptor binding site --> binds to ACHE in muscle membrane --> broken down to acetate + choline --> choline taken back up into axon Prevents spontaneous/continuous activation
What do rifamycin, streptomycin, erythromycin, chloramphenicol and tetracyclines affect?
Rifamycin inhibits RNA polymerase, streptomycin changes shape of small subunit, erthromycin prevents movement of ribosome along mRNA, chloramphenicol inhibits formation of peptide bond, tetracyclines interfere with tRNA attachment to mRNA-ribosome complex
What can spirometry be used for?
Used to assess prognosis of respiratory disease, quantify severity of disease, assess if lung disease present at early stage and the effect of thearpy
What are targeting sequences?
Used to direct protein to final destination. Removed when delivered out of nucleus but remain when delivered to nucleus for after mitosis
What substances have diuretic action?
Water, xanthines (caffeine), glucose, ethanol, carbonic anhydrase inhibitors
What is lubricin, what is it produced by and what is its function?
Water-soluble glycoprotein produced by chondrocytes and type II synoviocytes. Forms a thin superficial barrier that repels joint surface (due to repulsive -ve charged central part) to prevent contact of articular surfaces
What is the effect of heat stress on water balance?
Water/Na lost in sweat for thermoregulation so needs to be replaced by drinking Aldosterone production increased and ANP secretion decreased to decrease Na loss in urine
What is found in salivary secretions?
Amylase, lysozyme, HCO3, growth factors and haptocorrin/transcobalamin-I (binds and chaperones cobalamin/vitamin B12)
Describe the anterior and posterior longitudinal ligaments
Anterior longitudinal - thick and prevents hyperextension Posterior - weaker and prevents hyperflexion
What is lumbar lordosis, what can it cause and how is it corrected?
Anterior rotation of pelvis associated with weakened trunk muscles that produces increased lumbar curvature. Can cause spinal nerve root entrapment and corrected by strengthening abdominal muscles and stretching back extensors
Where does the anterior tibial artery run and where is dorsalis pedis pulse found?
Anterior tibial artery passes through interosseous membrane to anterior compartment. Dorsalis pedis found lateral to tendon of extensor hallucis longus
What are the anterior/posterior communicating arteries and when do they open?
Anterior/posterior communicating arteries are normally closed and give a collateral blood supply/open if difference in pressure
What are cell cycle inhibitors and examples?
Anti-mitotics that affect every cell, biologics are drugs that target essential tumor growth proteins, anti-microtubule agents (vinca-alkaloids that prevent formation or taxanes that prevent disassembly), inhibitors of mitotic kinases, kinesins and cohesin/kinetochore targeting
What is co-trimoxazole?
Antibiotic that prevents nucleotide synthesis. Acts on Gram +ve/-ve aerobic bacteria
Give an example of drugs that can't cross the BBB and how does this change in meningitis?
Antibiotics Meningeal inflammation breaks down BBB so allows penicillin to penetrate brain tissue
What are antibiotics and antimicrobials?
Antibiotics - natural antimicrobials made by micro-organisms. Antimicrobials - natural, semi-synthetic and synthetic chemicals that kill/inhibit micro-organism growth
Describe the portal circulation
Aorta --> coeliac trunk --> gut --> hepatic portal vein --> liver --> hepatic vein --> IVC
What structures are found in the pontine reticular formation and what do they do?
Apneustic (causes prolonged inspiration and allows voluntary breath holding) and pneumotaxic centres (controls breathing for vocalisation/singing by inhibiting apneustic centre but can't fully override medullary respiratory centre)
What apo interacts with adipocyte surface proteins, what is lipoprotein lipase and when is its activity high?
ApoC-II interacts with adipocyte surface proteins and stimulates lipoprotein lipase. LPL degrades TAG in chylomicron/VLDL --> glycerol + FA for uptake in adjacent cells. LPL activity is high after a meal and in muscle during starvation for FA oxidation
How do adjacent vertebrae articulate together?
Articulate between articular facets and between vertebral bodies
What are the types of glial cells and their functions?
Astrocytes - regulate environment around neurons and form part of BBB. Oligodendrocytes - make myelin sheath for CNS. Schwann cells - make myelin sheath for PNS. Microglial - macrophages for CNS and destroy bacteria. Ependymal - Have cilia that move CSF. Satellite - like astrocytes for PNS
What happens to pleural pressure during a respiratory cycle?
At beginning of inspiration it is slightly negative, but becomes more negative during inspiration as expansion of chest pulls outwards on lungs. Then becomes less negative to lead to quiet expiration
Describe how different pressure differences cause air to move in/out of the lungs
At beginning of respiratory tract, pressure = atmospheric pressure. If Pa = Patm then no airflow. If Pa > Patm then air flows out. If Pa < Patm then air flows in
What are the main NTs?
ACH, amino acid (glutamate, GABA, glycine), monoamines (noradrenaline, adrenaline, serotonin dopamine), neuropeptides and endorphins
What are the main NTs and which is used in reciprocal antagonistic inhibition in stretch reflexes?
ACH, glycine (inhibitory), glutamate (used in 1y sensory neurons), GABA (inhibitory) and biogenic amines (dopamine, 5-HT, noradrenaline). Glycine used as inhibitory NT in stretch reflexes
What are nicotinic agonist examples?
ACH/carbachol (mimics ACH and used for glaucoma) works at both NACHRs and MACHRs. Nicotine - selective for ganglionic and CNS over NMJ so for smoking cessation. Suxamethonium - acts as short term depolarising neuromuscular block
What is a start codon?
AUG codes for methionine and initiates transcription of a gene
What are the parts of the Na+ VGC?
Activation (closed when resting, opens very quickly on depolarisation) and inactivation (open when resting, closes slower on depolarisation) gate
What causes epidural haemorrhage and what are symptoms?
Acute skull trauma/fracture, usually arterial. No symptoms at first then severe headache as haematoma compresses brain. Must be treated with surgical intervention
What drug is used to treat HSV?
Acyclovir mimics guanosine and is pro-drug. Activated by HSV thymidine kinaseand causes DNA chain termination in replication
What cells provide adaptive and innate immunity and how are lymphocytes activated?
Adaptive - B and T lymphocytes, innate - monocytes, neutrophils, basophils, eosinophils. Immune cells develop in primary lymphoid tissues (bone marrow or thymus) and are activated in secondary lymphoid tissues
Describe the atlanto-occipital and atlanto-axial joints
Atlanto-occipital - condyloid synovial joint that allows flex/ext of C-spine Atlanto-axial - pivot synovial joint reinforced by transverse ligament encircling odontoid process
What is the neural auditory pathway?
Auditory sensation travels to cochlea nucleus --> mid pons relay (splits to travel bilaterally) --> superior olivary nucleus (spatial localisation)
What is drug inactivation?
B-lactamases cleave b-lactam ring so b-lactamase inhibitor (clavulinic acid or tazobactam) given with penicillins
What is absorbed in the ileum and colon and why is water needed?
B12, water, sodium, bile acids and intrinsic factors are absorbed in the ileum. A small amount of water, electrolytes and bile acids are absorbed in the colon. Water is needed for hydrolysis reactions, facilitation of absorption and propulsion and combination with mucin granules to make mucus
What is the structure of erythrocytes and their lifespan?
Biconcave with no nucleus/mitochondria. Lifespan of 120 days
Where does the abdominal aorta bifurcate, what does it bifucate into and what does this divide into (and what does each branch supply)?
Bifurcates at L4 into common iliac arteries which bifurcates into internal (pelvic viscera, pelvic wall and gluteal region) and external (lower limb) iliac arteries at S1/sacroiliac joint
What is the orbit and what are the orbit bones?
Bilateral pyramid-shaped cavity on anterior skull that houses eye, extra-ocular muscles and associated neurovasculature. Bones - frontal, zygomatic, lacrimal, ethmoid, sphenoid, maxilla
What is the structure of eosinophils and when are they increased?
Bilobed nucleus with orange staining granules. Increased in asthma, parasitic disease and skin disorders
What are the phases that allow drugs to be water soluble?
Biotransformation (conversion to water-soluble metabolite by adding/unmasking polar group) or synthesis (conjugation with glucose added)
What is the function of bipolar cells in the eye?
Bipolar cells convert continuous glutamate release from rod cells during dark into a varying depolarisation connect to ganglion cells that send axons into optic nerve
What is used for HIV treatment?
Blocking attachment, fusion inhibitors, reverse transcriptase inhibitors, integrase inhibitors and protease inhibitors. HAART uses different classes to maximise outcome
What are the components of blood, plasma and types of plasma proteins?
Blood - 55% plasma, 45% formed elements. Plasma - 90% water, 8% protein and 2% glucose, salts and other dissolved chemicals. Plasma proteins include fibrinogen (haemostasis), globulins (immunity) and albumin (transport and oncotic pressure)
What cells can form cancer stem cells?
Body stem cells, progenitor cells and differentiated cells
What are the types of bone marrow, what type do neonates have, what type has more adipocytes and where is red bone marrow found?
Bone marrow is either red or yellow (contains lots of adipocytes). Red bone marrow (haemopoietic) found in neonates but is replaced with yellow bone marrow as we develop. Red bone marrow still found in ribs, skull, pelvis and NOF
What happens to immune cells during lactation?
Breast blood vessels express MadCAM and some B cells leave PP and move to breast
How can we compensate for methaemoglobinaemia?
By increasing haematocrit above 45% (polycythaemia) to increase O2 carrying capacity
What vertebral levels is the larynx, what is its function and what tracts does it separate?
C3-C6 and is gateway between upper and lower airway, responsible for phonation and protection of lower airway. Separates digestive and respiratory tracts
What negatively regulates cell cycle progression?
CDKIs as they bind to and inhibit CDK function so prevent cell cycle regulation
What are CN I, II, III, VII, IX and X?
CN I - Olfactory, CN II - Optic, CN III - Oculomotor, CN VII - Facial, CN IX - Glosopharyngeal, CN X - Vagus
What are the families of cell adhesion molecules?
Cadherins, Ig super family, selectins, mucins and integrins
Describe insensitivity to anti-growth signals
Cancer cells not forced out of proliferative state into G0 so can permanently grow/divide
What are the shapes of the carotid canal (and where does it run) and jugular foramen and what does each hold?
Carotid canal is round and more anterior and holds internal carotid artery. Jugular foramen is oval-shaped and more posterior and holds jugular vein. Carotid canal runs anteriorly and medially into skull
Where is the carpal tunnel, what runs through it and what can be affected if the size of the carpal tunnel decreases
Carpal tunnel found at the base of the hand between the carpal bones and the flexor retinaculum. Tendons of FDS and FDP and median nerve run through carpal tunnel. Median nerve can be compressed
What is the function of blood?
Carriage of O2 and CO2, defense against infection, haemostasis, temperature, transport of substances
What are germinal centres?
Cause affinity maturation of B cell antibodies so they fit better to antigen. In 2y lymphoid organs
What is osteogenesis imperfecta?
Caused by defective type I collagen synthesis (non-conservative missense mutation) and causes brittle bones, abnormal teeth, thin skin and weak tendons
What is maple syrup urine disease and how is it treated?
Caused by deficiency in branched chain a-ketoacid dehydrogenase so unable to break down branched AAs so their keto acids build up and are excreted. Treated by giving carefully controlled amounts of AAs
What causes alkaptonuria, what does it cause and how is it treated?
Caused by deficiency in homogentisate-1,2-dioxygenase and causes black urine due to presence of alkapton and cardiac and joint problems (due to homogentisate deposits). Treated by diet restriction and lots of vitamin C
What is MCADD, what does it cause and how is it treated?
Caused by deficiency of medium-chain acyl CoA dehydrogenase of b-oxidation so causes ketoacidosis, hypoglycaemia and presence of fats. Treated with regular food to prevent need for b-oxidation
What causes osteoarthritis?
Caused by destruction of articular cartilage so bone-bone contact
What causes cardiac tamponade, what are the effects, signs and treatment?
Caused by excess fluid in serous pericardium and reduces ability of heart to pump blood as chambers compressed so reduces diastolic ventricular filling, SV and CO. Signs are raised JVP, hypotension with reflex tachycardia. Treated with pericardiocentesis (subxiphoid, parasternal or apical)
What is membrane fluidity?
Caused by flexing of acyl chains that can rotate within bilayer and diffuse laterally
What causes Dupuyten's contracture?
Caused by thickening of the palmar fascia that causes fixed flexion of the fingers
What is the appearance of SAH on CT?
Causes CSF system to fill with blood and appear white
What can vitamin B9 deficiency cause?
Causes neural tube defects
How does exercise affect BP?
Causes release of local vasodilators that increase blood flow to exercising muscle. Sympathetic outflow increases to constrict vessels to non-essential organs to compensate and increase vascular resistance and maintain total peripheral vascular resistance. Also increases HR and CO
How does cholera affect the intestines and how can it be treated?
Causes secretory diarrhoea by activating adenylyl cyclase --> increased cAMP --> apical CFTR channel opens --> increased efflux of Cl into lumen --> Na and H2O drawn into lumen. Treated using oral rehydration which increases Na absorption coupled with glucose to increase body H2O
What are the different stages seen in benign and malignant tumours?
Cell mutation --> hyperplasia (reversible) --> dysplasia --> carcinoma in situ --> invasive cancer
What is an ion channel-linked receptor?
Cell-surface receptor where signal molecule binds to receptor and causes opening of ion channel so ions flow into cell. Mediated by neurotransmitters
What are the upper limb superficial veins?
Cephalic (lateral) and basilic (medial). Superficial veins run through superficial fascia and drain into deep veins
What vessels are visible in the cubital fossa, what are the borders and what other structures run through it?
Cephalic, basilic and median cubital veins visible Borders - brachioradialis (lateral) and flexors (medial) Biceps tendon, brachial artery and median nerve also run through
What are the divisions of the cerebellum and the functions of each?
Cerebrocerebellum - skilled motor tasks Spinocerebellum - locomotion Vestibulocerebellum - balance and posture and eye movement
What is the structure of the spinal cord at cervical, thoracic, lumbar and sacral levels?
Cervical - lots of white matter, large ventral/dorsal horns Thoracic - lots of white matter, lateral horn (contains sympathetic nerve cell bodies) Lumbar - little white matter, large ventral/dorsal horns Sacral - very little white matter, predominantly grey matter
How are cervical and thoracic/lumbar/sacral/coccygeal spinal nerves named?
Cervical spinal nerves named according to vertebra below. Others named according to vertebra above
What is a point mutation and what are the different types? How is sickle cell anaemia caused?
Change in a single nucleotide in a gene. Silent - single nucleotide changed but no change in amino acid, conserved missense - change in nucleotide and different amino acid but similar properties, non-conservative missense - different amino acid with different properties, nonsense - causes premature stop codon. Sickle cell anaemia from non-conservative missense mutation where glutamic acid changed to valine so under hypoxic conditions, haemoglobin changes shape and makes RBCs sickle shaped
What are non-competitive inhibitors?
Change shape of active site by binding to allosteric site and preventing entry of substrate as incorrect shape. Only reversed by decreasing [I]
What is UC, symptoms, what can it lead to and how is it diagnosed?
Chronic inflammation restricted to the colon. Symptoms - bloody diarrhoea, abdo pain, fatigue, fever and weight loss. Can lead to colon perforation, severe bleeding, dehydration, systemic inflammation and colon cancer. Diagnosed with faecal calprotectin and colonoscopy
What joint does osteoarthritis commonly affect and why?
Commonly affects hip joint as it is a weight-bearing joint
What happens to ETC in hypoxic conditions?
Complex IV can't work so prevents ETC from working and causes back-up of electrons that can form reactive oxyen species that cause cellular damage
Where are voltage gated channels and what do they allow?
Concentrated in axon hillock and nodes of Ranvier. Allow movement of ions down diffusion gradient to create rapid changes in membrane potential
What is the general method of calculating conduction velocity of myelinated axons?
Conduction velocity = total axon diameter x 6
What are the consequences of PCA stroke?
Contralateral homonymous hemianopsia, reading/writing deficits and impaired memory
What structures can be seen around the ventricle system on sagittal MR?
Corpus callosum sits above lateral ventricles. Caudate nucleus found lateral to ventral horn of lateral ventricle and thalamus found either side of 3rd ventricle
How can correct mutant genes be delivered or faulty genes repaired?
Correct genes can be delivered using iPSCs/MSCs or using viral vectors and CRISPR-cas9 can alter, remove or add nucleotides
What parts of the adrenal glands secrete adrenaline and cortisol?
Cortex secretes cortisol and medulla secretes adrenaline
What parts of the brain work ipsilaterally and contralaterally?
Cortex works contralaterally and cerebellum works ipsilaterally
What is cortical bone, how thick is it in the epiphysis and diaphysis and what are the features of cancellous bone?
Cortical bone is compact bone that forms a thin capsule at the epiphysis and a thick layer around the diaphysis. Cancellous bone is much less dense, has a larger SA and is the site of bone marrow
What are the functions of the corticospinal, rubrospinal, vestibulospinal and reticulospinal tracts?
Corticospinal (pyramidal) - precise movement Rubrospinal (extrapyramidal) - gross movements (large muscles) and facilitates flexors Vestibulospinal/reticulospinal (extrapyramidal) - posture and balance and position of head and limbs
What is adult treatment for CD?
Corticosteroids (prednisolone), azothioprine and mercaptopurine (IBD immunosuppressants) and biological therapies (eg. infliximab to neutralise TNF)"
What methods are used in intracellular space?
Cytotoxic T cells, NK cells and T-cell dependent macrophage activation
What is base excision repair?
DNA glycosylase removes faulty base and DNA polymerase and ligase make new, correct nucleotide
What are the differences between DNA and RNA?
DNA has deoxyribose and thymine, RNA has ribose and uracil as less energy to make. Cytosine can deaminate to uracil
Outline a simple intracellular signalling pathway
EC signal molecule binds to receptor protein and activates cascade of intracellular signalling proteins that interact with target proteins that alter cellular behaviour
What is the role of the ECM?
ECM determines physical properties of tissues. Has a role as cell scaffold, cell migration, shape, proliferation, survival and tissue development. Calcified ECM in bones, little ECM in neurons, strong ECM in tendons and pliable ECM in dermis
What are EPSPs and IPSPs and examples?
EPSP - increases Na+ permeability (NACHRs). IPSP - increase K+ (MACHRs indirectly open K+ channels) or Cl- (GABAa) permeability
What are the stages of the cardiac cycle?
Early diastole - ventricles relax and pressure drops, closing semilunar valves and blood flows into atria. Late diastole - blood flows passively into ventricles. Atrial systole - forces small amount of additional blood into ventricles. 1st phase ventricular systole - AV valves close. 2nd phase ventricular systole - pressure rises and blood is expelled through semilunar valves
What is the course of the hypoglossal nerve and what does it provide?
Emerges from anterior medulla and runs through hypoglossal canal. Contains motor fibres that innervate tongue
What is the course of the spinal accessory nerve and what does it provide?
Emerges from first 5-6 cervical segments then runs superiorly through foramen magnum then leaves skull via jugular foramen. Gives motor supply to SCM and trapezius and found in posterior triangle of neck (made from SCM, trapezius and clavicle)
Where do dorsal column fibres end, where do upper and lower limb fibres project to and where do fibres decussate?
End in dorsal column nuclei (DCN) which is a column of cells extending from top of spinal cord to lower medulla (also contains 1st synapse). Fibres decussate in lower medulla
Describe the structure of lymphatic capillaries
Endothelium with large intercellular gaps surrounded by permeable BM and one-way valves for uni-directional flow
How can energy be stored?
Energy stored in chemical bonds (ATP, phosphocreatine), sugar molecules and by holding something away from eqm
What are exotoxins and endotoxins and examples?
Exotoxins (Gram -ve/+ve) can be cytolysins, act as enzymes (A/B proteins and neurotoxins) or activate immune response (superantigens). Endotoxins are LPS component of Gram -ve cell wall
How do you calculate FVC, what is normal FEV1/FVC ratio and what reduces this?
FVC = inspiratory reserve capacity + expiratory reserve capacity + tidal volume. Normal FEV1/FVC = 70-80% and reduced in obstructive disease (eg. asthma and COPD)
What are deltoids, what do they have a role in and what innervates them?
Fan shaped muscles that wrap around the shoulder and have a role in abduction, extension and flexion. Innervated by axillary nerve
How is lower limb length measured?
From ASIS to distal tip of medial malleolus
What steps must gluconeogenesis bypass and why?
G-6-P --> glucose , F-1,6-P --> F-6-P and pyruvate --> phosphoenolpyruvate. These steps must be bypassed as the enzymes in glycolysis are uni-directional
What is the goal of ICS and how do they work?
Goal of ICS is to decrease inflammation. Bind to glucocorticoid receptor (GR) --> translocates from cytoplasm to nucleus via nuclear pore complex (NPC) --> GR binds to glucocorticoid response elements (GRE) on DNA --> up-regulates anti-inflammatory gene expression or down-regulates pro-inflammatory gene expression
How do microbiome bacteria affect vitamin balance and what can bacterial overgrowth cause?
Gut microbiome bacteria are users/producers of vitamins B/K so bacterial overgrowth can cause vitamin imbalances
How can HER-2 mutations cane cancer?
HER-2 mutation causes spontaneous RTK dimerisation and activation of signalling pathway
How does HIV affect the gut?
HIV kills gut CD4 cells so he patient is vulnerable to gut infections from low grade pathogens
What happens in polycythaemia?
Haematocrit >60% so high blood viscosity and increased resistance and reduced flow, leading to end organ failure
How are mature B cells created?
Haemopoietic SCs --> pro-B cells --> pre-B cells --> immature B cells --> mature B cells
Where is the BBB more leaky?
Has fenestrated capillaries in circumventricular organs (around ventricular system, area postrema and subfornical organ)
What is the structure of the sphenoid bone?
Has greater and lesser wings, superior orbital fissure, optic canal, foramen rotundum and pterygoid plates
What are the causes of compartment syndrome in the hand and how are they treated?
Has iatrogenic and traumatic causes. Treated with fasciotomy (2 dorsal incisions, 1 lateral and 1 medial or carpal tunnel)
Describe the composition of the bone matrix
Has organic (35-40%type I collagen for tensile strength and proteoglycans for compressive strength and Ca binding) and inorganic (60%, mainly calcium hydroxyapatite crystals that coat collagen fibres to allow some flexibility) parts
What are molecular chaperones?
Help fold proteins and are elevated when cell under stress (heat). Provide protection from cytosol and prevent hydrophobic effect, using energy from ATP for folding
What structures connect the two hemispheres and the cortex to brainstem?
Hemispheres connected by corpus callosum and cortex connected to brainstem via internal capsule
What are intermediate filaments?
High tensile strength so in keratins in skin/hair and lamins. Keratin mutations can cause epidermalysis bullosa
What are properties of the hip articular capsule, what parts of femoral neck are intracapsular and what is the strongest ligament that strengthens the articular capsule?
Hip articular capsule is strong and thick. Anterior NOF and medial half of posterior NOF are intracapsular. Anterior iliofemoral ligament is the strongest ligament
What muscles are used during swing phase?
Hip flexors to lift leg off ground then hip extensors (gluteus maximus) to stop thigh momentum at end of swing. Hamstrings flex knee to lift swinging leg off ground. Dorsiflexors active throughout
What are the types of polysaccharides?
Homopolymers (made from one residue) or heteropolymers (made from multiple different residues)
What are the main barriers to CNS repair?
Hostile environment (scar tissue and myelin-associated inhibitory proteins) and poor regenerative response
What does exercise testing involve?
How far someone can walk, breathlessness on exercise, treadmill or bicycle exercise
What are the main IC and EC buffers?
IC - phosphate, AA and haemoglobin. EC - carbonic acid, AA and plasma protein
What IL causes class switching to IgE?
IL-4
What antibodies are produced by activated B cells?
IgM initially produced then class switch to produce IgG. Ig specificity maintained
Where are baroreceptors found?
In carotid sinus (above carotid artery bifurcation) and aortic sinus (above aortic valve)
What does the limbic system inculde and what is it involved in?
Includes hippocampus and amygdala for emotion and memory formation
What are index, 1y, 2y and 3y cases?
Index case - 1st identified case. 1y - case that brings infection to population. 2y - infected by 1y. 3y - infected by 2y
What are inflammatory and anti-inflammatory cytokines?
Inflammatory - IL-1, TNF, IL-6. Anti-inflammatory - IL-10 and TGF
What is IgF2?
Insulin-like growth factor 2. Males produce IgF2 and females produce IgF2 receptors and imbalance can influence size of baby
What is the role of the GI tract?
Intake of food, digestion/absorption of nutrients and H2O and removal of waste
What is senescence?
Irreversible proliferative arrest that functions as self-defense mechanism against proliferation of damaged cells
What are primary issues of pharmacological treatment?
Issues related to pathology of disease (eg. pathophysiology and choice of target)
What is the most important channel in maintaining membrane potential?
K channels
What is KRAS?
KRAS is a GTPase. Inactive when bound to GDP and active when bound to GTP to activate downstream signalling proteins. GTPase mutation means can't break down GTP so always active and promoting growth signals
What does knee stability depend on ?
Knee stability depends on strength and actions of surrounding muscles and ligaments that connect tibia and femur
What is the function of the LOS, what is reflux and what is GORD?
LOS prevents reflux of gastric acid into oesophagus. Reflux is the retrograde flow of gastric contents into the oesophagus. GORD is a condition where reflux of stomach contents causes symptoms/complications
What forms the lesser and greater omentum and how is the omental apron form?
Lesser omentum formed by ventral mesentery and greater omentum formed by dorsal mesentery. Omental apron formed where dorsal mesogastrium moves in front of transverse colon to connect with the mesocolon
What AAs are ketogenic and why?
Leucine, lysine, isoleucine, phenylalanine, tryptophan and tyrosine are ketogenic as they are converted to acetyl CoA or acetoacetyl CoA
Where do the liver and stomach develop and how do the viscera become orientated?
Liver develops in dorsal mesogastrium and stomach develops in ventral mesogastrium. Viscera become orientated as mesenteries rotate in cavity
What are M1, M2 and M3 receptors?
M1 (stomach), M2 (heart) and M3 (exocrine glands and smooth muscle). M1 and M3 are excitatory and M2 is inhibitory
What types of molecules attract small inorganic ions?
Macromolecules (highly charged) and small organic molecules attract counterions that can affect osmotic gradient
How does leukocyte extravasation work?
Macrophage with microbes releases cytokines, then glycoproteins on leukocyte bind to endothelium and cell rolls using integrins. Once fully bound, leukocyte can migrate through endothelium into ECM
What are the major hip abductors and what are the innervated by?
Major hip abductors (all innervated by superior gluteal nerve) - tensor fascia lata, gluteus medius and minimus
What are the major hip adductors and what are they innervated by?
Major hip adductors found in medial compartment of thigh and innervated by obturator nerve
What molecules can cross the BBB?
Many lipophilic molecules (eg. heroin) so rapidly reach brain cells after IV injection Some molecules pass into brain ECF via special transport system
What is inflammation of the cranial cavity membrane and how is it diagnosed?
Meningitis, diagnosed with lumbar puncture into L4 subarachnoid space so less risk of damage to spinal cord
What are the different types of mAbs?
Mice (-omab), humanised (-zumab), chimeric (-ximab) and human (-umab)
What makes up the cytoskeleton?
Microfilaments, intermediate filaments and microtubules
How is UC treated?
Mild/moderate symptoms - aminosalicylates (sulphasalazine, mesalazine) and corticosteroids (eg. prednisolone) Severe symptoms - biological therapies (eg. infliximab to neutralise TNF) and IV ciclosporin Surgical colectomy also offered to remove diseased colon
What do parasympathetic agonists do?
Mimic action of ACH and activate MACHRs or prevent breakdown of ACH
What is the hydrophobic effect and what is the exception?
Minimises SA of hydrophobic portions so hydrophobic parts of protein towards centre. Membrane proteins opposite are exception
What are the types of mutations?
Missense (conserving and non-conservative) where single nucleotide changed, nonsense where premature stop codon reached, insertion and deletion of nucleotides and splice site mutations
What are some variations of the CoW?
Missing PCoA, missing/small ACoA or ACA, abnormal origin of PCA from ICA
What is the adrenal medulla?
Modified ganglia. Preganglionic fibres stimulate release of adrenaline/noradrenaline, contributing to mass action
What happens to urea in the kidney?
Most urea pumped out of collecting ducts into medulla. Some passes back into ascending limb of loop of Henle and some is lost in urine
What are transmembrane proteins?
Mostly made from alpha helices enriched in non-polar AAs with glycosylated extraceullar domains
What is the structure of motor and sensory neurons?
Motor - cell body with dendrites at one end of myelinated axon Sensory - cell body in centre of myelinated axon with dendrites at end
What makes up motor end plates and terminal boutons?
Motor axon divides into many terminal branches (motor end plates) as it approaches myofibril At end plate, branches form bulbous presynaptic axon terminal (terminal bouton)
What are drug efflux pumps?
Multi-drug resistant efflux pump genes integrated into plasmid so can be transferred. Overexpression of pumps allow high level of resistance
Can dopamine or L-Dopa reach the brain after peripheral administration and what does oral L-Dopa administration cause?
Neither can reach the brain Oral administration causes peripheral conversion to dopamine which causes intense vomiting
What type of receptors aren't found in heart and brain and why?
No alpha receptors in heart and no adrenoreceptors in brain so that blood flow is never reduced
What is the process of osteoprogenitor cell maturation and what does each type do?
Osteopreogenitor cell (in periosteum or endosteum) --> osteoblast (makes new bone matrix) --> osteocyte (embedded in matrix and maintains bone) Osteoclasts (multinucleate modified macrophages) come from haemopoietic SCs and remove bone
How does appositional growth occur?
Osteoprogenitors in periosteum develop into osteoblasts that form ridges on either side fo periosteal blood vessel --> ridges fuse together to enclose blood vessel --> inside tunnel periosteum becomes endosteum and osteoblasts make new bone lamellae that fill tunnel --> as bone thickens inside bone removed by osteoclasts to maintain cortical bone thickness
What are the outer, middle and inner layers of the eye?
Outer - cornea at front and sclera at back (fuses with dura around optic nerve) Middle - uvea (includes iris, choroid and ciliary body) Inner - retina
What is a feature of pacemaker cells and how is this different to atrial/ventricular cells?
Pacemaker cells show automaticity (depolarise spontaneously) whereas atrial/ventricular cells only spontaneous in disease
What are the types of cell communcation?
Paracrine (act on local cells using NTs from nerves) and endocrine (act on distant cells and transported through blood)
What does Brown-Sequard syndrome cause?
Paralysis and loss of proprioception, vibration and discriminative touch on ipsilateral side and loss of pain and temperature sensation on contralateral side of lesion
What do parasympathetic and sympathetic nerves do to the SAN and what effect does blood-borne adrenaline have?
Parasympathetic (from vagus) decrease HR via K+ channels closure with MACHRs. Sympathetic increases HR and inotropy by increasing rate of closure of channels by beta adrenoreceptors. Blood-borne adrenaline acts on beta receptors to increase inotropy
What is the pentose phosphate pathway?
Pentose phosphate pathway important for biosynthesis, creating NADPH for fat and steroid hormone synthesis. Products can be fed back into glycolysis as G-6-P and glyceraldehyde-3-phosphate
What can a perforation in the posterior wall of the stomach cause and how are peritonitis patients positioned?
Perforation in posterior stomach wall can cause fluid in the lesser sac. Peritonitis patients positioned sitting up so that fluid passes down paracolic gutters to pelvis where toxin absorption is slower
What are the CD8 cell proteins that kill infected cells?
Perforins (create pores in cell membrane) and granzymes (proteases and DNases and trigger caspase activation). Perforins open pores that allow movement of ions and membrane depolarisation, flipping transmembrane proteins and moving granzymes into cell
What are persistent foetal circulation and persistent pulmonary hypertension of the newborn?
Persistent foetal circulation where body unable to transfer from foetal to normal circulation. Associated with PPHN where alveolar arterioles fail to open, meaning pulmonary vascular resistance remains high and causes hypoxemia due to right-to-left shunting
What causes pes cavus and pes planus?
Pes cavus (high arch) - hypertonic muscles Pes planus (flat foot) - hypotonic muscles
What methods are used in extracellular space?
Phagocytosis, antimicrobial peptides and antibodies
What is the 1st step of glycolysis, why is it important and what are the fates of G-6-P?
Phosphorylation of glucose --> glucose-6-phosphate. Important as G-6-P can't leave the cell. G-6-P can be used for pentose phosphate pathway, glycogen synthesis and glycolysis
What is cytokine pleiotropy, redundancy, synergy and antagonism?
Pleiotropy - can have many effects. Redundancy - some have same job. Synergy - act together to cause effect. Antagonism - can have opposite effects
What is pleomorphism and abnormal mitosis?
Pleomorphism is lots of different shapes and sizes of cells. Abnormal mitosis can be an increased mitotic rate or tri/tetra/multipolar spindles
What is seen in pneumothorax and COPD CXRs?
Pneumothorax - airway deviation, reduced lung markings. COPD - flattened hemidiaphragms, bullae, hyperinflation
What are examples of point mutations, chromosomal rearrangement and gene amplification?
Point mutation - KRAS single nucleotide exchange. Chromosomal rearrangement - BCL-2 anti-apoptotic protein, gene amplification - c-MYC
What are the types of RNA polymerase and what do they code for?
Pol I - rRNA, Pol II - snRNA, mRNA, Pol III - tRNA
What are examples of inactivated vaccines and what are the risks?
Poliovirus, influenza and hepatitis A, eliminates infectivity but risk of incomplete inactivation and immunity often brief
How does the RF modulate via histamine?
Posterior hypothalamus tuberomamillary nucleus (TMN) produces arousal so lesions or anti-histamines can cause hypersomnia
Descibe the venous drainage of the thoracic region
Posterior intercostal veins drain into azygos (right) or hemiazygos (left) veins. Anterior intercostal veins drain into internal thoracic vein
What is flat back syndrome and what causes it?
Posterior pelvic tilt to pull lumbar spine flat Caused by ankylosing spondylytis, degenerative discs or spinal fusion
What types of cells are in premalignant and malignant tumours?
Premalignant - even mix of proliferating and apoptotic/senescent cells. Malignant - more proliferating cells than apoptotic/senescent cells
How do ACEi work?
Prevent conversion of angiotensin I into angiotensin II using ACE. Decrease blood pressure by decreasing SVR from vasodilation
Where do axons from LGN project, where do fibres mediating vision from upper quadrants loop and how can this structure be damaged unilaterally?
Project to visual cortex via opic radiation. Loop more anteriorly via Meyer's loop. Unilateral damage can be caused by tumour/stroke
What are enzymes and how do they work?
Proteins that catalyse reactions by providing alternate route of reaction with lower Ea
What is the role of myelin?
Provides resistance to ion flow which is lost at nodes of Ranvier, causing saltatory conduction
What are quantitative and qualitative mutations?
Quantitative - affects amount of gene product. Qualitative - affects type of gene product
What does an FBC show?
RBCs, Hb (mean cell Hb and mean cell [Hb]), cell/plasma contents (haematocrit), platelets and white cells
What is used to calculate RPF and what is the normal value?
RPF calculated using PAH as it is completely filtered and excreted. Normal value 600-700ml.min
Compare the radial and ulnar styloid processes
Radial styloid process larger and more distal than ulnar styloid process
How does the RF modulate via serotonin/5-HT?
Raphe nuclei inhibits GABA cells to produce arousal and modulate pain perception Damage to brainstem RF can therefore lead to coma Deficits lead to OCD, depression, anxiety and aggression Drugs targeting 5-HT receptors (eg. anxiolytics, anti-migraine, anti-depressants) affect mood
What does the Na+/K+ ATPase do in neurons?
Rebalances action of leak channels. Exchanges 3Na+ out for 2K+ in, giving extracellular space +ve voltage wrt intracellular
Why are ADH and oxytocin released from posterior pituitary?
Released from posterior pituitary to enable rapid response to stimulus
What does renin do?
Renin converts angiotensinogen (from liver) into angiotensin I which is converted into angiotensin II in the lungs using ACE
What information is in viral genome?
Replication of viral genome, assembly and packaging of genome, regulation and timing of replication, modulation of host defences and spread to other cells
How does DNA replication occur?
Replication starts at origins of replication and goes in 5' to 3' direction of new strand. Forms replication fork with leading strand and lagging strand (forms Okazaki fragments)
What is elastin?
Required for flexibility in blood vessels, lungs, ligaments and skin and is rich in glycine and proline. Coated with fibrillin to limit stretch
What are virus-like particles and advantages?
Resemble structure of virus and provoke humoral and cellular response (HPV). Contain no genetic material so safe and cost effective
What do free nerve endings respond to, what are they often called and what do they detect and cause?
Respond to chemical stimuli (eg. pH or chemicals in ECF) and mechanical displacement. Often called polymodal nociceptors and detect local tissue damage and produce sensation of local pain
What are immature RBCs called and what is a high count of them indicative of?
Reticulocytes. High count indicative of excess RBC loss/destruction
What movements do rhomboids and levator scapulae have a role in?
Rhomboids - scapula retraction Levator scapulae - scapula elevation
Where does the posterior tibial artery run, what does it give off and how does it reach the sole of the foot?
Run in the posterior compartment of leg then through tarsal tunnel behind medial malleolus to reach sole of foot. Gives off fibular branch
Describe the arrangement of neurovascular bundles
Run in upper portion of intercostal space in costal groove. VAN (superior to inferior)
Where does the supraspinatus tendon run and what is impingement syndrome?
Runs below AC joint. Impingement caused where space for tendon decreased so pain on first 15deg of abduction
What are the branches of the SMA?
SMA gives off ileocolic artery (gives off appendicular artery), right and middle colic arteries, inferior pancreaticoduodenal artery and jejunal/ileal branches that run through mesentery
What is the route blood takes through the heart?
SVC/IVC --> RA --> tricuspid valve --> RV --> pulmonary valve --> pulmonary trunk --> L/R pulmonary arteries --> 4x pulmonary veins --> LA --> mitral valve --> LV --> aortic valve --> ascending aorta
What are the major nerves from the sacral plexus?
Sacral nerve gives off sciatic nerve (branches into tibial and common peroneal nerves) and superior/inferior gluteal nerves
Describe the structure of the sacrum and coccyx
Sacrum - large triangular wedge of bone made from 5 fused vertebrae Coccyx - small triangular bone made from 4 fused vertebrae
What can streptococcus pyogenes cause?
Scarlet fever, cellulitis and erysipelas (acute infection of upper dermis)
Why does late repair cause worse outcomes and worse PNS axons regeneration?
Significantly reduced number of motor neurons and axons that can regenerate. Schwann cells downregulate regeneration-associated factors. Prolonged muscle denervation causes muscle atrophy/fibrosis and profound decrease in numbers of regenerating axons through deteriorating intramuscular sheath
Describe the structure of the RA
Smooth posterior wall and rough anterior wall. Fossa ovalis on right side and SAN below entry of SVC
What does MR measure and what contrast is used?
Spin of protons in H2O IV gadolinium contrast alters T1 and doesn't cross intact BBB
How are staphylococci and streptococci divided?
Staphylococci - coagulase test (S. aureus is +ve). Streptococci are divided into beta-haemolytic (destroys RBCs), alpha-haemolytic (changes colour of plate) and non-haemolytic
Where does translation start and what are reading frames?
Starts at N-terminus at AUG/start codon at 5' end of codon. Reading frame determined by start codon and deletion/insertion mutations can shift them
What are the differences between systemic and pulmonary arteries
Systemic - thick muscular walls and moderate diameter. Pulmonary - thin elastic walls and larger diameter
What is prehypertension?
Systolic 120-139mmHg or diastolic 80-89mmHg
What are tachyphylaxis and tolerance?
Tachyphylaxis - acute tolerance to a drug. Tolerance is chronic from longer-term administration of a drug
What is the unhappy triad?
Tearing of medial meniscus, ACL and tibial collateral ligament
How can cancer cells have limitless replicative potential?
Telomeres are maintained so apoptosis/senescence prevented
What separates cerebrum and cerebellum and where are motor and somatosensory cortexes?
Tentorium cerebelli Motor in precentral gyrus and somatosensory in postcentral gyrus
What are pharmacokinetic genetics?
Test the genome of a patient to see how they would interact with a medication (metabolism, elimination, distribution) and the dose required
What is sensitivity testing and different types?
Tests if therapy likely to be effective. Dilution test, disc diffusion tests and microtitres determine minimum inhibitory concentration (MIC). Microbe can be susceptible (high likelihood of therapeutic success), intermediate (uncertain therapeutic success) or resistant (likely therapeutic failure) and determined by breakpoint conc
What is Laplace's law and why can arterioles withstand arterial pressure despite thinner walls?
The smaller the radius of a vessel, the greater the pressure that its walls can withstand so arterioles can withstand arterial pressure due to small lumen radius
How is diversity in B cell receptors generated?
Through VDJ recombination. D-J joining where DNA spliced out, then V-DJ joining where more DNA spliced out. Then transcription, RNA splicing and translation to create final heavy chain assembled with light chain
How can drugs interact with receptors?
Through covalent bonds (very strong, irreversible), electrostatic forces (ionic attraction, H bonds), lipophilic interaction and Van der Waals (weak)
What is half life and how is it calculated?
Time taken for conc to half. T1/2 = (Vd/Cl) x 0.7
What are the layers of the pericardium?
Tough fibrous pericardium prevents over-dilation and serous pericardium (parietal and visceral in serous sac that allows lubrication and movement)
How can oedema be treated?
Treat underlying cause. Treated using osmotic (promote water excretion) or loop diuretics (promote Na excretion)
What are the types of helminths?
Trematodes (flat, non-segmented), nematodes (roundworms) and cestodes (flat, segmented)
What are symptoms of Parkinson's?
Tremor, rigidity, slow movement, slurred speech and affected gait with irreversible progression
What is PIGD and what are the impacts of genome sequencing?
Uses IVF to create blastomere then small group of cells taken for testing. If genetic disorders excluded, embryo can be implanted
What is ultrasound and what are the pros/cons?
Uses sound waves in range of 1-18MHz so is safe during fetal development. Is cheap and readily available but difficult to interpret
What is MRI and what are the pros/cons. What type of MRI is used for pathological changes?
Uses very strong magnetic fields and produces high contrast images of soft tissue. Uses non-ionising radiation and T2 for pathological change
What is CT and how does it work?
Uses x-rays from many angles to produce 3D image of patient.
How can NMJ be stimulated medically, what is the effect and what is the function of atropine in nerve agent treatment?
Using ACHE inhibitors (neostigmine/physostigmine) which make NMJ hyperactive so muscle convulses and becomes paralysed Atropine is NACHR antagonist so allows removal of nerve agent
How can glucose be moved against conc gradient?
Using Na+/K+ pump and ATP, Na+ pumped out and K+ in. Co-transport is coupled with movement of glucose into cell
How are sound cues localised?
Using interaural time difference (ITD) and interaural level difference (ILD) ITD - difference between times sounds reach two ears, useful at low frequency ILD - difference in sound pressure level reaching two ears and useful at high frequencies
What is the popliteal artery and how can you tell the anterior tibial from the posterior tibial artery?
Where femoral artery passes through gap in tendon of abductor magnus (abductor hiatus) and enters popliteal fossa. Anterior tibital has horizontal section
What is Turner syndrome?
X, 1 in 5000 females
What are normal ranges for pH, PaO2, PaCO2, [HCO3] and base excess?
pH - 7.35 - 7.45, PaO2 > 11kPa, PaCO2 - 4.7-6.0kPa, [HCO3] - 22-26mmol/L and base excess +/- 2mEq/L
What are the primary and secondary vertebral curves?
"1y - thoracic and sacral kyphoses. Develop during foetal development 2y - cervical and lumbar lordoses. More evident when baby holds up head and walks 2y curves allows most movement with little movement in 1y curves
What steps in glycolysis allow for further ATP production?
"3-phosphoglycerate --(phosphoglyceromutase)--> 2-phosphoglycerate --(enolase)--> phosphoenolpyruvate --(pyruvate kinase)--> pyruvate ATP production driven via ubstable enol"
How is IgA transported across the epithelium?
"IgA J chain binds to polymeric Ig receptor on basolateral membrane --> allows uptake into endosome --> transported through cell --> secretory IgA released on apical membrane
What is PDC, what are the 3 stages and why is it unidirectional?
"PDC is a 3 stage enzyme that converts pyruvate --> acetyl CoA. Unidirectional under physiological conditions as involves loss of CO2. Pyruvate dehydrogenase decarboxylates pyruvate and adds acetyl group to TPP --> dihydrolipoamide acyltransferase transfers acetyl group to lipoamide to produce acetyl CoA --> dihydrolipoyl dehydrogenase catalyses electron transfer to allow NADH production
Describe the cartilaginous skeleton of the larynx and the ligaments
"Paired cartilage - arytenoid (vocal cord attachment), corniculate (on top of arytenoid) and cuneiform (anterior to corniculate)
Describe the different types of muscle in athletes and the properties of each
"Type I slow twitch - develop tension slowly and use oxidative metabolism from glucose and longer term FAs. Rich in mitochondria, have lots of capillaries, low glycolytic capacity and an intermediate glycogen content Type IIa fast twitch - develop tension quickly and use anaerobic respiration via glycolysis but also aerobic respiration due to myoglobin. Has intermediate capillary density, high oxidative capacity, high glycolytic capacity and intermediate glycogen content Type IIb fast twitch - develop tension quickly and use only anaerobic respiraiton. Has low capillary density, low oxidative capacity, high glycolytic capacity and high glycogen content
What processes occur after an axon is damaged?
1. Damage to sensory neuron causes burst of APs 2. Disruption of retrograde flow of trophic support 3. Burst of APs and lack of neurotrophic factors causes 'positive injury signal' release 4. Cells in DRG alter phenotype to switch from transmission state to growth state (decrease ion channels and proteins involved in neurotransmission and increase proteins involved in axonal growth) 5. Wallerian degeneration at distal end and retrograde degeneration also begins depending on extent on injury 6. Can lead to 1y afferent terminal atrophy to cause loss of input, disinhibition, spontaneous activity and eventually cell death
How does ACH release cause smooth muscle contraction?
ACH binds to M3 GPCR --> increased phospholipase C --> increased IP3 --> IP3 binds to IP3R on ER --> triggers Ca release from ER --> Ca binds to CaM and MLCK --> CaM-MLCK phosphorylates myosin light chain --> actin-myosin cross linking --> smooth muscle contraction
How would muscle fatigue be regulated when holding an object in a given position?
1. Input from corticospinal tract activates biceps motor neuron 2. Muscle starts to fatigue so contracts less strongly and stretches which activates muscle spindles 3. Increased AP frequency to spinal cord so more synaptic input to motor neurons to increase force of contraction
What is acetylcholine/ACH?
ACH is inhibitory in cardiac muscle but excitatory in skeletal muscle
What is the process of the accommodation reflex?
1. Pupillary constriction (same pathway as pupillary light reflex) improves focussing on close objects and improves depth of field 2. Thickening of lens (ciliary muscle contracts so suspensory ligaments are relaxed so lens rounds to greater strength) 3. Convergence of eyes via medial rectus muscles innervated by CN III
How does ACH release cause Ca release in muscles?
ACH released from synaptic vesicles --> binds to NACHR in folded muscle sarcolemma --> NACHR activated --> AP in sarcolemma --> AP travels down T tubules --> Ca release from SR into sarcoplasm
What is the function of ADH?
ADH opens aquaporins in collecting duct, stimulating water reabsorption to increase blood volume. This creates a small amount of concentrated urine
What is the volume of conducting airways and what does the gas present do to inhaled gas?
150-200ml of gas which dilutes newly inhaled gas
What are the different types of fluid and what are the compositions?
2/3 intracellular fluid and 1/3 extracellular fluid (made from 3/4 interstitial fluid and 1/4 plasma). ECF has high Na+/Cl- and low K+ and ICF has high K+ and low Na+/Cl-
What is first-line maintenance therapy, asthma relievers and add-on therapies for asthma and first-line therapy for COPD?
1st line maintenance is ICS, asthma reliever is SABA and add-on therapy to ICS is LABA. 1st line for COPD is LABA/LAMA
What are heart sounds?
1st sound - AV valves closing. 2nd sound - semilunar valves closing. S3 - early diastole due to turbulence in rapid filling of ventricles. S4 - turbulent flow in late filling from decreased ventricular compliance
What is primary and secondary lymphoedema?
1y lymphoedema - genetic malformation of lymphatics. 2y lymphoedema - damage to lymphatics (surgery or radiation therapy, obstruction from fibrosis, tissue injury or inflammation)
Why do inherited mutations in tumour suppressors cause earlier development of cancer?
2 hits needed for tumourigenesis, but in inherited cancer, 1 hit already present so only 1 more needed
How is AMR spreading and in what type of bacteria is it spreading most?
AMR increasing most in Gram -ve. Due to intrinsic/mutational resistance, plasmid encoded resistance and acquired resistance.
What do 20secs and 5mins of anoxia lead to and how is brain blood flow regulated?
20secs leads to unconsciousness and >5mins leads to permanent unconsciousness/coma. Blood flow auto-regulated (roughyl 50ml per 100g per min if cerebral perfusion pressure between 60-160mmHg).
How many divisions are in the airway and in which sections does respiration occur?
23 divisions, respiration occurs in final 7 divisions
Describe the process by which ketone bodies are made
2x acetyl CoA --(acetoacetyl CoA thiolase)--> acetoacetyl CoA Acetoacetyl CoA + acetyl CoA --(HMG CoA synthase)--> HMG CoA HMG CoA --(HMG CoA lyase)--> acetoacetate Acetoacetate --(b-hydroxybutyrate dehydrogenase)--> hydroxybutyric acid
What do 2y neurons form in DCML pathway and where do these fibres synapse and project to?
2y neurons form medial lemniscus (tract that travels to somatosensory thalamus). Then synapse in ventro-postero-lateral (VPL) nucleus and axons project to somatosensory cortex
What is different about the superior part of the sympathetic chain and what does it do?
3 cervical ganglia don't connect to ventral root but to thoracic chain below. Superior ganglion is largest. Provide sympathetic innervation to head (iris, skin and salivary glands)
How does AMP affect glycogen phosphorylase and glycolysis?
AMP is an activator of glycogen phosphorylase only when not phosphorylated to promote glycogen breakdown. AMP also activates enzymes at start of glycolysis (activates PFK1)
How does AMPK mediate the shift from glucose to FA metabolism during prolonged exercise?
AMPK mediates shift from glucose to FA metabolism by inhibiting acetyl CoA carboxylase enzyme (convertes acetyl CoA --> malonyl CoA). Therefore, reduces [malonyl CoA] so less inhibition of carnitine shuttle so more FA transport into mitochondria for oxidation
What is the 3y structure?
3D structure of a protein, held together by interactions between R groups
Describes venous drainage of the heart
Venous drainage drains into coronary sinus (posterior surface) which drains into RA
How can mRNA move out nuclear membrane?
5' cap recognised by cap-binding complex in nuclear membrane and allows mRNA to leave through pore
What occurs at the 5' and 3' ends of RNA?
5' capping adds 7-methyl guanosine and uses capping enzymes to protect from degradation and for translation recognition. 3' Poly(A) tail formed and protects from degradation
What are differences between 5' and 3' ends?
5' end has phosphate group and 3' end has unpaired OH group
What are the pharmacological intervention algorithms for different patient groups?
A (under 55yo) or D (over 55yo or Afro-Carribean) --> A + C --> A + C + D --> A + C + D + further diuertic or alpha/beta blocker. A is ACEi, C is CCB and D is thiazide-like diuretic
What processes produce NH3, how is NH3 processed, what could raised serum urea indicate and how does liver failure impact protein metabolism?
AA deamination and gut bacteria produce NH3. NH3 --> NH4 --> urea. Raised serum urea can indicate gastric bleed, kidney failure or dehydration. Liver failure impairs protein metabolism
What does AA deamination produce, what effect does this have on the TCA and what can this cause in astrocytes?
AA deamination produces NH3. Excess NH3 impairs TCA cycle as it depletes a-ketoglutarate due to equilibrium. Causes excess glutamine in astrocytes which increases osmotic pressure and astrocyte pressure
What are AAs used for?
AAs are used for body protein synthesis, glucose and ketone body synthesis (for ATP synthesis), purine/pyrimidine/porphyrin/thyroxine synthesis, NTs (glutamate, noradrenaline), coenzymes and melanin
Describe the post-absorptive phase of protein digestion
AAs transported by facilitated diffusion
How does AMPK affect glucose transports and how can it affect glycolysis?
AMPK promotes movement of GLUT4 to membrane independently of insulin. Also activates PFK2 by phosphorylation, forming F-2,6-BP which promotes PFK1 activity
Describe the acromioclavicular joint and what is the typical trauma mechanism to this joint?
AC joint is a plane synovial joint (allows gliding movement) and doesn't have any muscles that cross it. Typical trauma mechanism is a force that depresses the shoulder girdle
What are ACE inhibitors and angiotensin receptor antagonists?
ACEi (captopril, -pril) block ACE so prevent formation of angiotensin II and angiotensin receptor antagonists (losartan, -tan) block angiotensin receptors
What is the structure of a NACHR and what non-NT molecules act as neuromodiulators?
ACH binding site on a subunit. d and y subunits help shape ACH binding sockets. Inflammatory mediators (eg. PGE2 and bradykinin) act as neuromodulators
What is a plexus and where are they not found?
A branching network of nerves. Not found in thoracic nerves 2-12 as direct to intercostal muscles
What are the cells found within the Islets of Langerhans?
A cells (secrete glucagon), b cells (secrete insulin), delta cells (produce somatostatin), PP cells (produce pancreatic polypeptide) and epsilon cells (produce ghrelin
What is the cavernous sinus, what structures run through it and how can infection from face involve cavernous sinus?
A dural venous sinus in dura mater either side of sella turcica that contains large group of veins. ICA passes through and CN III, IV, V1 and V2 superior to inferior run on lateral wall with CN VI next to ICA. Facial infection can track back into cavernous sinus to cause cavernous sinus thrombosis to produce cranial nerve signs
What is the greater omentum?
A large flap of loose CT and fat from greater curvature of the stomach to the transverse colon. It is quite vascular from gastroepiploic arteries
What are mutations and in what cells do they occur?
A spontaneous change in cellular DNA. Occur in somatic cells (affect daughter cells) or germ cells (affect next generation). Can be +ve and cause evolutionary change or -ve and cause disease
What is heparin?
A sulphated polysaccharide anticoagulant that binds to antithrombin to cause conformational change so thrombin and Xa bind better
What are blood groups?
A, B and O blood groups have differnet oligosaccharides attached to surface glycoproteins. Group A has A oligosaccharide, group B has B oligosaccharide, group AB has A and B oligosaccharides and group O has precursor H oligosaccharide
What are selective alpha agonist examples?
A1 - phenylephrine for vasoconstriction and nasal decongestant. A2 - clonidine antihypertensive (inhibits NE release)
What are selective alpha antagonists?
A1 - prazosin/tamsulosin/doxazosin are antihypertensives. A2 - yohimbine (not used)
What antibiotics work on ribosomes and how?
Aminoglycosides (streptomycin) bind to 30s and cause incorrect shape and reading. Tetracyclines (doxycycline) interfere with tRNA attachment. Chloramphenicol binds to 50s and prevents peptide bond formation. Macrolides (erythromycin, clarithromycin) and lincosamides (clindamycin) binds to 50s and prevent translocation of peptide chain
What are amniocentesis, CVS and non-invasive prenatal testing for Down syndrome?
Amniocentesis - sample of amniotic fluid taken (15-18 weeks) transabdominally. CVS - sample of placental tissue (12-14 weeks) transabdominally or transcervically. Both under ultrasound guidance. Non-invasive prenatal testing uses ultrasound of nuchal translucency (fluid at back of neck) or sample of maternal plasma
What is lung compliance and what does this compensate for?
Amount of change in volume for a given change in pressure. Compensates for reduced perfusion of lung apex. Basal alveoli more ventilated as they have higher compliance so bigger volume change per unit pressure change
What is anaemia, anaemic Hb concentrations and how does the kidney compensate?
Anaemia is low [Hb]. <130g/L in males or <115g/L in females. Kidney compensates due to renal hypoxia which stimulates EPO formation and RBC production
What are anatomical, alveolar and physiological dead space and when does alveolar dead space increase?
Anatomical dead space - amount of air in space up to terminal bronchioles (mouth, pharynx trachea and bronchi). Alveolar dead space - alveoli that have insufficient blood supply to act as effective respiratory membranes (increases with age and respiratory disease). Physiological dead space = anatomical dead space + alveolar dead space
What are the other physiological characteristics of cancer cells?
Angiogenesis, evade immune system, deregulate cellular energetics and can metastasise
What does angiotensin II do?
Angiotensin II passes into arterial blood and acts on GPCRs to activate phospholipase C and increase cytosolic [Ca2+] which triggers smooth muscle contraction in systemic arterioles, raising TPR and afterload and BP
What are the compartments of the thigh, what nerve innervates each, what muscle groups are found in each and what movements do they cause?
Anterior (femoral nerve, L2-4) - quadriceps for hip flexion and knee extension Medial (obturator nerve, L2-4) - adductors for hip adduction Posterior (tibial nerve, L5-S2) - hamstrings for hip extension and knee flexion
What are the fossa in the skull base and what does each hold?
Anterior (holds frontal lobe), middle (holds temporal lobes) and posterior (holds cerebellum) fossa
What is intrinsic and acquired resistance?
Intrinsic - due to inherent structural or functional characteristics. Acquired from mutations and horizontal gene transfer
What makes up articular cartilage, what are the characteristics of it and what are the layers?
Articular cartilage made from smooth layer of hyaline cartilage that has a very low friction coefficient and an elastic structure to act as a shock absorber. Deeper layers merge with subchondral bone via calfified layer and ECM contains H2O, proteoglycans and collagen type II. Has inner (secretes synovial fluid) and outer (fibrous capsule) layers
What are the articulations found in the knee?
Articulation between lateral femoral and lateral tibial condyles, medial femoral and medial tibial condyles and between patella and femur
What are the subtalar joints, what do they allow and what muscles invert/evert the foot?
Articulations of talus with calcaneus and navicular. Allow inversion/eversion to allow foot to adjust to different surfaces Fibularis longus/brevis evert and tibialis anterior/posterior invert
What is Boyle's law?
As the volume of a gas increases, the pressure exerted by it decreases
Where does the external ileac artery become femoral artery and where is the femoral pulse found?
Becomes femoral artery when it passes under inguinal ligament. Femoral pulse found halfway between ASIS and pubic symphysis
Describe the luminal phase of protein digestion
Begins in stomach with pepsin (activated from pepsinogen when makes contact with HCL from parietal cells)
What NTs and receptors are used between neurons and between postganglionic neurons and target tissue in parasympathetic and sympathetic systems?
Between neurons - ACH and NACHRs for excitatory response in both systems. Postganglionic and target tissue - parasympathetic - ACH and MACHRs (inhibitory and excitatory), sympathetic - NE and adrenoreceptors
What is found in bile, what do bile salts do, how is it reabsorbed and what regulated primary bile acid synthesis?
Bile is mainly water, but also contains bile salts, bilirubin and cholesterol. Bile salts aid absorption of lipophilic substances (FAs, monoglycerides, cholesterol and fat-soluble vitamins). Reabsorbed via enterohepatic circulation and regulated by FXR signalling
What is 2,3-DPG?
Binds loosely to Hb and enhances O2 release in hypoxic tissue
What causes depression and what are symptoms?
Dysfunction in activity of monoamine systems in brain to cause insufficient serotonin and noradrenaline Symptoms - low mood, lack of energy, disrupted sleep, loss of interest and tiredness
What are the different parts of a ribosome?
E (exit) site, P (peptidyl-tRNA) site and A (aminoacyl-tRNA) site and mRNA channel in small subunit
What are excitatory postsynaptic potentials (EPSP) and inhibitory postsynaptic potentials (IPSP)?
EPSPs make it more likely to cause action potential (glutamate and ACH cause Na+ entry). IPSPs decrease membrane ability to reach threshold (GABA and glycine cause Cl- entry)
What movements occur in the TMJ during early and late phase mouth opening and what movements does the TMJ allow?
Early phase - condyle rolls slightly anteriorly Late phase - condyle and articular disc slide forwards Allows elevation, depression, protrusion, retraction
What are the neurological targets of ecstasy, cocaine, heroin, nicotine and ketamine?
Ecstasy - increases monoamine release Cocaine - reduces monoamine uptake Heroin - Mu opioid receptor agonist Nicotine - NACHR agonist Ketamine - NMDA glutamate receptor antagonist
What epithelia arises from each germ layer?
Ectoderm - epidermis, glandular breast tissue. Mesoderm - ovaries. Endoderm - lungs, liver, stomach and pancreas
What tissue arises from each germ layer?
Ectoderm - epithelia, nerve tissue. Mesoderm - epithelia, connective tissue and bone. Endoderm - epithelia
What cells are formed from each embryonic layer?
Ectoderm - skin and neuron, mesoderm - cardiac, smooth and skeletal muscle and RBCs, endoderm - lung, thyroid and pancreatic cells
What are pharmacogenomics?
Effect that individual genetics have on metabolism of drug. Different individuals have different responses to the same drug
What can excessive ketone bodies cause, how does insulin prevent ketogenesis and how is this affected in diabetics?
Excessive ketone bodies can cause ketoacidosis. Insulin inhibits ketone body production by preventing release of fat from adipose tissue, preventing transport of FAs into mitochondria and decreasing transcriptinal levels of HMG CoA synthase. Therefore diabetics have more release of fat from adipose tissue, more transport into mitochondria and higher levels of HMG CoA synthase
What is hyperplasia and examples?
Excessive number of cells. Seen in benign prostatic hyperplasia and atypical lobular/ductal hyperplasia in breass
What structural divisions does the dura create?
Extends between hemispheres to form falx and separates cerebrum from cerebellum by tentorium cerebelli. Brainstem passes through gap (tentorial incisure) in tentorium
What affects drug distribution into major body fluids?
Extent of binding to plasma proteins and barriers (placenta, BBB, gut)
What is the process that causes the pupillary light reflex?
Fibres from retina project to pretectal nucleus in superior colliculi then bifurcate to project bilaterally to E-W nuclei. Parasympathetic preganglionic fibres from E-W nucleus synapse in ciliary ganglia in orbit and postganglionic fibres enter eye to act on sphincter muscles to constrict pupils 'In on II, out on III'
What is collagen and what disease can it cause?
Fibrous protein (most abundant in body and type I most common) and has high tensile strength. Ehlers-Danlos syndrome (EDS) results from mutation
What is collagen?
Fibrous protein with strong 3D structure. 3 staggered polypeptide chains with H bonds between. Many prolines provide strength (pro-pro-gly)
What controls filtration of water into Bowman's capsule and what is the normal net filtration pressure?
Filtration of water controlled by balance between constriction of afferent and efferent arterioles. Osmotic and hydrostatic pressures. Normal net filtration pressure is 10mmHg.
What are x-rays and how do they work? What are the views?
Fire beam of x-rays at pt and are detected by sensor. Dense tissue absorbs x-rays and appear white and soft tissue doesn't so appears black. AP and lateral views (for appendicular) and PA view (most used as less distortion of heart field
What divisions of the airway are conducting and respiratory and where does gas exchange occur?
First 16 divisions are conducting and last 7 are respiratory. Gas exchange occurs in alveolar ducts and sacs
What happens during elongation?
First AA binds to P site then another in A site. Peptide chain transferred from P site to A site then mRNA shifts by one codon until stop codon
What are the function of the colon and rectum and what is diverticular disease?
For absorption of water and electrolytes. Diverticular disease is little pouches into mucosa that can cause problems when infected
Describe nucleosomal fibres
Formed from DNA wrapped around histones (H2A, H2B, H3 and H4), linker DNA and linker histone (H1)
What are the features of fibrous joints, what movement do they allow and what are the different types of fibrous joints?
Have no synovial cavity and hold together articulating bones with fibrous connective tissue with little-no movement. Can be sutures (skull), synostosis (ossified suture so immovable), syndesmosis (sheet of fibrous tissue between bones) or gomphosis (cone-shaped peg fits into a pocket)
What bones and joints are involved in movement of the shoulder joint and what is the pectoral girdle?
Humerus, scapula and clavicle are involved in shoulder joint movement along with glenohumeral joint, acromioclavicular joint, scapulothoracic joint and sternoclaviclar joint. Pectoral girdle is an incomplete ring of bones that attaches the shoulder joint to the axial skeleton
How do Na levels impact the RAAS?
Hyponatremia detected by macula densa or DCT stimulates renin release to cause Na and H2O reabsorption and increase blood volume
What are the structures and types of antibodies?
IgG, IgM (pentamer), IgE, IgD, IgA (dimer). Contain heavy/constant (controls antibody) and light/variable regions (for antigen binding) and disulphide bonds between chains
What is the vertebral level of iliac crests and where does spinal cord end?
Iliac crests at L4 and spinal cord ends L1/L2 in adults
What is the function of hair cells in the cochlea?
Inner hair cells convert cochlear vibrations into nerve signal by releasing glutamate onto afferent axons Organ of Corti displacement stimulates mechanically-gated ion channels in inner hair cell stereocilia Outer hair cells (innervated by motor axons) improve frequency discrimination Hair cell stereocilia interact with tectorial membrane
What do neurons in prevertebral ganglia innervate and what nerves do they form?
Innervate abdominal viscera. T5-T9 = greater splanchnic nerve and T10-T12 = lesser splanchnic nerve (celiac region innervates stomach, small intestine, spleen, pancreas and kidneys). Some pass through and synapse in superior mesenteric ganglion
What is the function of the right hemisphere regions equivalent to Broca's/Wernicke's areas and what do lesions of this area cause?
Involved in tasks requiring non-semantic speech recognition and generation (intonation, rhythym and emphasis of speech) and non-language communication skills (body language, gestures). Lesions of this area cause robotic, monotonous speech
What is used as contrast for CTA?
Iodine
What are ionotropic and metabotropic receptors?
Ionotropic receptors (very fast) - ligand gated ion channels open pores for ions. Metabotropic (slower) - activates G proteins that affect enzymes.
What is the effect of different glutamate receptors on GABA receptors?
Ionotropic receptors increase GABA receptor dispersion and metabotropic receptors increase GABA receptor accumulation
What are the proteins on the inner nuclear membrane and what diseases can they cause?
Lamin and emerin. Can cause laminopathies (rare diseases with obscure pathophysiology) such as Hutchinson-Gilford progeria syndrome (early ageing) and Emery-Dreifuss muscular dystropy (disease of skeletal and cardiac muscle)
How is gas transfer measured?
Measured by comparing end-tidal/alveolar O2 (using oxygen meter) and arterial PaO2 (using pulse oximeter)
What are beta antagonists?
Non-selective - propranolol. B1 - atenolol (decreases HR and contractility)
What is the structure of NACHRs?
Normally pentameric (heteromeric with 2 alpha subunits and 3 beta subunits)
What are the P, Q, R and S waves?
P - start of atrial depolarisation. Q - due to early depolarisation of left side of septum. R - start of depolarisation of apex. S - spread of depolarisation to base of ventricles
What is the fascia of the palm and hand dorsum continuous with, where is fascia thick/thin in the hand and what binds the midpalmar and thenar potential spaces?
Palmar and dorsal fascia continuous with antebrachial fascia. Fascia is thick in central palmar region (palmar aponeurosis) and thin over thenar/hypothenar muscles. Midpalmar and thenar potential spaces bound by fibrous muscle septa
Descibe how insulin is synthesised
Pancreatic b cells produce preproinsulin --> proinsulin --> insulin. Endopeptidases cleave of C peptide and insulin + c peptide are stored
Explain post-transcriptional phosphorylation, disulphides, cleavage, ubiquitination and deamination of proteins
Phosphorylation can activate/deactivate genes using kinase/phosphatase. Disulphides can form between cysteine molecules. Cleavage is removal of portion of gene. Ubiquitination is where small protein added to another and acts in signalling and degradation. Deamination is natural but can be reduced by removing reactive species from cell, can cause protein damage from structural changes
Describe the chest leads
Placed around anterior chest. V1/V2 are mainly -ve, V3/V4 are bipolar, V5/V6 are mainly +ve. QRS normally bipolar on all
Describe the structure of a haem group and why does oxygen bond reversibly?
Planar electrons bonded to N atoms in porphyrin ring. Histidine group (binds free H+) binds below plane and oxygen can bind above plane. Oxygen binds reversibly due to steric hinderance from other parts of molecule
What is stacatto gait?
Plantarflexor paralysis (tibial nerve/calcaneal tendon damage) stops forward thrust so unaffected limb never advances beyond affected limb
What happens in mitosis?
Prophase (nuclear membrane breaks down, chromosomes condense, spindle forms), prometaphase (spindle joins to kinetochore), metaphase (spindle contracts, pulling chromatids apart), anaphase (spindle contracts so chromatids reach poles), telophase (nuclear envelope reforms, chromosomes uncoil), cytokinesis (actin and myosin contractile ring pinches cell until cleaves into 2 cells)
What is found at the gastroduodenual junction, what are Brunner's glands, where does most absorption occur and where does it continue?
Pyloric sphincter (thickening of circular layer of muscularis propria to form anatomical sphincter). Brunner's glands in duodenal submucosa secrete thin alkaline mucous. Most absorption occurs in jejunum as it is well-adapted with villi to increase SA and continues in ileum which has lots of GALT/Peyer's patches
What systems do UMNs fall into and what are they?
Pyramidal (brain to spinal cord via corticospinal tract) and extrapyramidal (brainstem to spinal cord, more primitive) systems
What are the bases and characteristics?
Pyrimidines - Thymine, cytosine, purines - guanine, adenine. CG form 3 H-bonds, AT form 2 H-bonds
What converts pyruvate to acetyl CoA and how are AAs and fatty acids converted to pyruvate?
Pyruvate dehydrogenase complex converts pyruvate --> acetyl CoA. AAs transaminated to alanine which is converted to pyruvate and FAs converted to pyruvate via b-oxidation
How do SAMA/LAMA and SABA/LABA work?
SAMA/LAMAs block binding of AHC to M3 to prevent smooth muscle contraction. SABA/LABAs bind to b2 receptors to trigger cascade of signal transduction to cause smooth muscle relaxation
What increases the SA of the small intestine and what processes occur at the top and bottom of villi?
SA increased by villi and microvilli. Stem cells found at base of intestinal crypt help to form villi and at the top of villi epithelial cells are removed
What happens during quiet and forced expiration?
Quiet expiration - passive due to elastic recoil. Forced expiration - internal intercostals, quadratus lumborum and anterior abdominal muscles
What muscles are used during quiet and forced inspiration?
Quiet inspiration - diaphragm and external intercostals. Forced inspiration - diaphragm, external intercostals, serratus anterior, pectoralis major/minor and SCM
What muscles are used for quiet and deep inspiration and quiet and forced expiration?
Quiet inspiration - external intercostals and diaphragm. Deep inspiration - accessory muscles (SCM, pectoralis major/minor, serratus anterior and scalene). Quiet expiration - elastic recoil. Forced expiration - internal intercostals and abdominal muscles
What is R0, what does it show and how can it be used?
R0 - number of new cases generated per infected case over infectious period. R0 = new cases/old cases (R0<1 means infection dies out). 1/R0 is proportion of susceptible individuals (epidemic threshold) and 1-1/R0 is proportion to be vaccinated to eliminate
What causes subdural haemorrhage and how does it progress
Rapid acceleration/decelaration of head which moves brain relative to skull so shears bridging veins so slow onset of symptoms
What is clearance and how is it calculated?
Rate of elimination compared to conc remaining. Cl = rate of elimination/conc remaining
How is SV maintained in exercise and what are the changes in the lungs during exercise?
SV maintained by atrial contraction. Respiration depth and rate increases, increasing pulmonary pO2 and relaxing pulmonary bronchioles and increasing lung perfusion
What metabolic diseases are neonates screened for?
Screened for MCADD, PKU, maple syrup urine disease, isovaleric acidaemia, glutaric aciduria type 1 and homocystinuria
What are lipid rafts?
Specialised domains enriched in sphingolipid and cholesterol that limit lateral diffusion and group lipids and proteins with shared functions
What organs are found in the abdominal cavity?
Stomach under left dome of diaphragm --> duodenum (posterior wall and curves around pancreas) --> jejunum --> ileum --> cecum (appendix attached) --> ascending colon --> transverse colon --> descending colon --> sigmoid colon --> rectum --> anus. Also, spleen posterior on left and kidneys (retroperitoneal) posterior with left kidney higher.
Where is the superior oesophageal sphincter found, what is the role and innervation of the stylopharyngeus and what is the gag reflex?
Super oesophageal sphincter found inferior to inferior constrictor muscle. Stylopharyngeus elevates pharynx during swallowing and innervated by glossopharyngeal nerve. Gag reflex stimulated by touching posterior wall of pharynx and involves brisk and brief elevation of soft palate and pharyngeal muscle contraction
What is the venous drainage of the brain?
Superficial cerebral veins cross subarachnoid space and bridging veins pierce dura to enter intracranial/dural venous sinuses.
Where do the rotator cuff muscles attach?
Supraspinatus, infraspinatus and teres minor attach to great tuberosity Subscapularis attaches to lesser tuberosity
How are TAGs hydrolysed, what is this sensitive to, what else does lipolysis use and what controls this?
TAGs are hydrolysed using hormone-sensitive lipase which is sensitive to insulin (inhibits HSL) and glucagon/adrenaline (stimulate HSL). Lipolysis also uses adipose triglyceride lipase to form diacylglycerol and this is controlled by expression level
What happens in TB?
TB hides inside macrophages and Th1 IFN activates macrophages to kill bacteria. Th1 cells wall off infected macrophages to form caseating granuloma
Where does tibial nerve run, what does it provide sensory innervation to, what causes tibial nerve palsy and what does this cause?
Tibial nerve runs through tarsal tunnel behind medial malleolus and provides sensory innervation to sole of foot. Tibial nerve palsy due to tibial fractures or compression in tarsal tunnel. Causes loss of sensation to sole of foot and plantarflexor paralysis
What are the therapeutic window, safe range and accumulation?
Therapeutic window - time where drug has therapeutic effect, safe range - between minimum therapeutic dose and minimum toxic dose, accumulation - where conc of drug increases as not all drug eliminated (5 half lives needed)
How is PMF used in babies?
Thermogenin in brown adipose tissue uses PMF from mitochondria to create heat
Where are types of specialised/unspecialised cells found?
Totipotent - zygote (ability to become any cell), pluripotent - developing embryo (can become nearly any cell), unipotent - can regenerate new cells of one lineage
Where does the trapezius muscle run, what innervates it and what movements does it cause?
Trapezius muscles run from occipital bone, cervical and thoracic vertebra to spine of scapula and lateral end of clavicle. Innervated by accessory nerve (CN XI). Has a role in scapula elevation and depression and retraction
What do L1-L2 sympathetic fibres do and where do they travel?
Travel in lumbar splanchnic nerve and synapse in inferior mesenteric ganglion. Innervate transverse and distal colon, rectum, bladder and genitals
How is infection of the hand compartments treated and what must you be careful with?
Treated with debridement of thenar space down to carpal tunnel
What is Patau syndrome?
Trisomy 13, 1 in 5000 births and affects mostly midline structures
What MSK injuries is CT useful for?
Undisplaced/impacted fractures (eg. especially scaphoid and NOF) and also skull injuries (eg. acute subdural haematoma)
What are DEXA scans?
Use 2 low-energy x-ray beams and give better image than x-rays with less radiaiton
What does injury to recurrent laryngeal nerve cause?
Vocal cord paralysis so causes dysphonia/hoarseness
What are the augmented leads?
aVR - points to right axilla, aVL - points to left axilla, aVF - points to feet
What are the types of viruses wrt genetic info?
dsDNA, ssDNA, +ssRNA, -ssRNA, dsRNA, ssRNA-RT or dsDNA-RT
What are the features of a chromosome?
p arm (short) and q (long). Telomeres with protective DNA and protein cap to protect from degradation, centromere joins two chromatids. G-light bands have lots of DNA, are CG rich and replicate early, G-dark bands are gene poor, AT rich and replicate late
What are spliceosomes, how are they formed and how are introns removed?
snRNPs form spliceosomes when bound to pre-mRNA and can remove introns by creating Lariats are excising introns and ligating exons
What are the orders of elimination?
0 order - constant quantity eliminated per unit time. 1st order - elimination of constant fraction per time unit and proportional to drug conc
What is dysplasia, it's characteristics and how is it graded?
Abnormal growth and graded depending on extent of spread through tissue. Characteristics include hyperchromatism, high nucleus:cytoplasm ratio, enlarged nucleoli, increased mitotic activity
What is scoliosis, what causes it and how is it stopped?
Abnormal lateral curvature with rotation of vertebrae, commonly in pubertal girls and clearer when bending forwards Caused by developmental defects, asymmetric muscle strength, poor posture or idiopathic Stopped by wearing brace or surgery
What are absolute and relative refractory periods?
Absolute - Na+ VGCs haven't reset so another action potential is impossible. Relative - Na+ channels have reset and threshold can be reached if large stimulus given
How a type of cell and organ regulate weight?
Adipocytes release factors that target hypothalamus to control feeding and maintain weight Intestinal transit time can be altered to alter absorption rate
What is the function of the 5' UTR?
Affects translational efficiency and can prevent ribosome loading
Where is airway resistance highest, why do we change to breathing through mouth during exercise, why is there resistance to airflow in lower respiratory tract (bronchi/bronchioles) and what changes resistance of small bronchi and bronchioles?
Airway resistance highest in URT with highest resistance in nose. Change to mouth during exercise as less resistance than nose. Resistance in LRT as effect of increased cross-sectional area not great enough to balance decreased airway diameter. Both hormonal and nervous input change resistance of small bronchi and bronchioles
What is the function of Akt in the insulin pathway?
Akt stimulates glucose uptake via GLUT4 and also phosphorylates/inactivates glycogen synthase kinase so glycogen synthase remains active for glycogen synthesis
What are the main glucogenic AAs, what AAs aren't glucogenic when can other AAs be used?
Alanine and glutamine are main glucogenic AAs and lysine and leucine are glucogenic if they can produce oxaloacetate or pyruvate from their breakdown
What are the anatomical features found on the anterior, posterior and lateral sides of the scapula?
Anterior - coracoid process and subscapula fossa Posterior - spine of scapula, infra/supraspinatous fossa and acromion Lateral - glenoid fossa
What are the CNS glial cells?
Astrocytes - lots of dendrite-like processes Ependymal - form lining of ventricles and central canal Oligodendrocytes - form CNS neuron myelin sheath Microglia - immune cells
What features divide atria and ventricles and the left and right ventricles (and what are found there)?
Atria and ventricles divided by atrioventricular sulcus/coronary groove and ventricles are divided by interventricular sulcus (anterior - LAD, posterior - PDA)
How does atropine affect the pupillary light reflex?
Atropine (muscarinic antagonist) blocks cholinergic synapse at eye so prevents miosis
How are mAbs produced?
B cell fused with tumour cell to produce immortal B cell that produces monoclonal antibodies. mAbs can be used to increase immune activity (treat cancer) or reduce it (Crohn's, psoriasis, MS, asthma, T1 diabetes)
Describe the blood supply and oxygen requirement of the brain
Brain has collateral blood supply through Circle of Willis. Brain has high oxygen demand so receives 20% cardiac output
What are the muscles found in the anterior compartment of the arm?
BBC muscles - biceps brachii, brachialis and coracobrachialis Biceps brachii (shoulder/elbow flexor and powerful supinator) has long (lateral to supraglenoid tubercle) and short head (medial to coracoid process) Brachialis is distal humerus to coronoid process of ulna and flexes in all positions Coracobrachialis - flexes and adducts shoulder and resists dislocation
What happens if BP high?
BP high --> more stimulation of stretch receptors --> vasomotor centre increases parasympathetic and decreases sympathetic outflow --> vasodilation, decreased HR and reduced CO
What happens if BP low?
BP low --> decreased stretching of receptors --> less frequent action potentials --> vasomotor centre inhibits parasympathetic and stimulates sympathetic outflow --> cause peripheral vasoconstriction, increasing TPR and BP
What does gait analysis involve?
Balance, co-ordination, walking rhythm, change of speed/direction and stride length
How is malaria diagnosed?
Blood film of RBCs (plasmodium visible inside cells)
What are the superficial and deep palmar arches, what are the metacarpal and digital arteries and what is the Allen test?
Branches of radial (deep arch) and ulnar (superficial arch) arteries. Metacarpal and digital arteries arise from palmar arches and supply fingers. Allen test - hand exsanguinated by making fist and applying pressure, pt opens hand and either artery released and capillary refill of hand tested
What is end-joining
Break in DNA and degradation of ends needs repair. Non-homologous (2 strands joined together) and homologous (complete sequence restored from by copying DNA from 2nd chromosome) end joins
What are quinolones and how do they work?
Broad spectrum, inhibit DNA synthesis and promote DNA cleavage by targeting topoisomerase II and IV
Where are Broca's area and insula found, what is the function of the insula and what is the opercular cortex?
Broca's area found in left temporal lobe just above lateral sulcus. Insula found under lateral sulcus and control some speech functions. Opercular cortex found on upper and lower lips of lateral fissue and is correlated with language production
Describe the mucosal phase of carbohydrate digestion
Brush border enzymes (eg. sucrase, lactase, limit dextrinase) complete digestion. Glucose and galactose enter cell via Na-linked 2y active transport and fructose enters by facilitated diffusion.
What is C diff associated with, what does it cause and how is it treated?
C diff associated with excessive broad-spectrum antibiotic usage (opportunistic over-growth). Causes abdominal pain and watery diarrhoea. Treated by stopping antibiotic usage, using vancomycin or metronidazole and FMT
What triggers cholesystokinin release, what does it do, what triggers secretin release and what does it do?
CCK release stimulated by FAs in duodenum and causes contraction of gall bladder. Secretin release triggered by acidic chyme in duodenum and stimulates biliary ductal cells
What hormones control gluconeogenesis and how is gluconeogenesis excessive in diabetes?
Controlled by glucagon, adrenaline and insulin. Glucagon affects control through cAMP and controlling PKA and therefore pyruvate dehydrogenase, PFK1 and FBPase1. Both glucagon and adrenaline activate hepatic gluconeogenesis. Gluconeogenesis excessive in diabetes as increased precursors (glycerol, AAs) and fatty acids and also increase in glucagon:insulin ratio
What controls preload?
Controlled by one-way valves in veins, muscular pumps and thoraco-abdominal pump (thoracic pressure decrease pulls blood into IVC)
What controls glycogen synthase activity?
Controlled by phosphorylation. Protein kinase A and phosphorylase kinase (both controlled by cAMP which is controlled by glucagon (liver) and adrenaline (muscle)) phosphorylate and deactivate GS. Dephosphorylation promoted by insulin through activation of protein phosphatase-1
What does the ENS control?
Controls gut motility, nutrient uptake, hormone and enzyme release, appetite regulation, vascular tone and immune cell activity
What are conventional and unconventional T cells?
Conventional - Th1 and Th2. Unconventional - NKT cells, intraepithelial lymphocytes (IELs) and gamma-delta cells
What are the characteristics of the SNS?
Convergence (postganglionic receives input from many preganglionic) and divergence (one preganglionic connects to different levels)
What are the features of thoracic vertebrae?
Costal facets that articulate with ribs and long inferior-pointing spinous process. Heart-shaped vertebral body and circular vertebral foramen
What is the function of astrocyte end feet?
Cover free surface of neuronal dendrites/cell bodies and all CNS blood vessels to separate from neural tissue
What are the main body cavities?
Cranial (continuous with vertebral canal), thoracic (ends at diaphragm), abdominal and pelvic
What are the cranial bones and what bones do the sagittal, coronal and lambdoid sutures connect?
Cranial bones - frontal, parietal, occipital, temporal, ethmoid, sphenoid Sagittal suture connects two parietal bones. Coronal suture connects frontal bone to parietal bones. Lambdoid suture connects parietal bones to occipital bone
How are cranial nerves different to spinal nerves and what are the CNs that innervate the the face, mouth and oesophagus?
Cranial nerves can be sensory, motor, special sensory or parasympathetic but spinal nerves are sensory and motor. CNV - trigeminal, CNVII - facial, CNIX - glossopharyngeal, CNX - vagus and CNXII - hypoglossal
What sites are created by spinal cord trauma, what structure is formed and what is the function of this structure?
Creates 1y site of cell death that rapidly spreads into 2y site of cell death. Glial scar formed by macrophages and microglia that engulfs debris, seals lesion site, repairs BBB and expresses chemicals that inhibit axon growth
What diseases can be caused by chromosomal aberrations?
Cri du chat from partial deletion of 5p and 90% in germ cell. Di George syndrome from deletion of region of 22q. Heritable peripheral neuropathy Charcot Marie Tooth disease (CMT1A) from duplication of 17p. XX male syndrome from translocation of SRY gene from Y to X chromosome. Turner syndrome only survivable monosomy and triploid babies miscarry or die in 1st year
How is genetic material exchanged in meiosis?
Crossing over of chiasmata during prometaphase I between non-sister chromatids of homologous chromosomes
What is the Gram staining procedure and what colour are different bacteria? What can't be detected/stained?
Crystal violet stain --> iodine --> alcohol wash --> safranin. Gram +ve retain crystal violet (purple) and Gram -ve take up safranin (pink). Spirochaetes (too thin) and TB (waxy capsulte) can't be detected
Why do antimicrobials exhibit selective toxicity?
Due to bacterial 70s ribosomes, peptidoglycan cell wall and different biochemistry
Describe the position of the duodenum, the parts of it, where the gall bladder and bile duct drain into and what do the folds to the membrane inside the duodenum make?
Duodenum is retroperitoneal and runs around head of the pancreas. Has superior, descending, horizontal and ascending portions and gall bladder and bile duct drain into descending portion. Folds to membrane inside duodenum make up plicae circulares
What are the layers of meninges?
Dura - attached to skull with periosteal and meningeal layers fused together Arachnoid - outer compact layer of barrier cells and inner trabecular meshwork Pia mater - thin membrane tightly attached to basement lamina of brain
What are the layers of the meninges, where is CSF found and where is it produced?
Dura mater, arachnoid mater and pia mater. CSF found in subarachnoid space and produced in ventricles
How is excess nitrogen secreted, when does intake exceed output and when does output exceed intake?
Excess nitrogen secreted in urine as urea formed in liver. Intake exceeds output during periods of growth and pregnancy. Output exceeds intake in trauma, fasting, body protein breakdown, protein malnutrition
What is the course of the vagus nerve and what does it provide?
Emerges from lateral surface of medulla with glossopharyngeal nerve to exit skull via jugular foramen. Provides motor supply to soft palate, pharynx and oesophagus, general sensory and motor supply to larynx (gives off superior laryngeal and recurrent laryngeal nerves) and is major parasympathetic nerve to the body
What is the course of the glossopharyngeal nerve and what does it provide?
Emerges from lateral surface of medulla with vagus nerve to exit skull via jugular foramen. Provides special and general sensory fibres to posterior tongue, parasympathetic fibres to parotid gland, general sensory to carotid body/sinus (give info about blood pressure and O2 saturation respectively), general sensory to pharynx and motor supply to stylopharyngeus
What is the course of the facial nerve?
Emerges from pons and passes through internal acoustic meatus to run through facial canal in petrous temporal bone and exit via stylomastoid foramen
What are transcription factors and activators?
Enable formation of preinitiation complex and bind to enhancer if promoting preinitiation complex formation or silencer if preventing. Activators modify proteins and leave space for RNA polymerase to bind
What does two hormone mechanism for release of anterior pituitary hormones enable?
Enables more complex and precise dual negative feedback control for hormone release
How do stem cells divide and where are SC populations found?
Either divide symmetrically (2x SCs or 2x specialised cells) or asymmetrically (1x SC and 1x specialised cell). Populations found in bone marrow, neurons, hair, skin, gut and muscle
What are the properties of articular cartilage, what are the 4 layers in it and what is the tide mark?
Elastic (chock absorber) and very low friction coefficient. Has resting, proliferative, hypertrophic and calcified layers (superficial to deep). Tide mark shows border of calcified layer
What contributes to the elastic properties of the lung?
Elastic properties from collagen and elastic fibres and surface tension forces from alveolar-liquid interface
What are the courses of the branches of the trigeminal nerve and what do the branches convey?
Emerges from lateral pons and splits V1 - traverses superior orbital fissure to enter orbit and emerges via supraorbital foramen V2 - passes through foramen rotundum and emerges via infraorbital foramen V3 - passes through foramen ovale and emerges via mental foramen All branches convey sensory inervation and V3 also carries motor fibres for muscles of mastication
What initiates feeding behaviour?
External (sight and smell of food) and internal cues (stomach contractions and [glucose, insulin, ghrelin, CCK and leptin])
What provides the blood supply to the extracranial head and neck and what are its branches?
External carotid artery. Branches are superior thyroid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, maxillary, superficial temporal
What muscles are found in the chest wall?
External intercostals (end anteriorly at midclavicular line, for inspiration), internal intercostals (deficient posteriorly, for expiration) and innermost intercostals
What are the main respiratory muscles?
External intercostals, serratus anterior (from scapula), pectoralis minor and major (superficial), rectus abdominis and SCM
What are the two groups of muscles in the hand and what are each of them for?
Extrinsic (for strength and power) and intrinsic (for precision) muscles
How are femur and tibia positioned, how does this create a stable mechanical axis, what is the Q line and what causes unequal loading of weight across tibial condyles?
Femur positioned diagonally and tibia positioned vertically to allow knee joint directly under hip joint. Q line is line from ASIS to centre of patella (men - 14 degrees, women - 17 degrees). Genu varum (small q angle) and genu valgum (large q angle) causes unequal weight loading
What are microtubules?
For cell scaffold and mitotic spindle fibres, cilia and flagella for locomotion. Target for taxane anti-cancer drugs
Describe the process of gut fat and cholesterol uptake
Gut fat and cholesterol packaged in chylomicrons (rich in apoB48 and A) --> chylomicrons interact with HDL which give chylomicrons apoC-II and apoE --> apoC-II helps with chylomicron unloading in adipose tissue --> apoE allows binding of chylomicron remnant to liver where it is metabolised
What do gut microbiota live off and what do they produce?
Gut microbiota live off of undigested food in lumen and produce SCFAs that impact gut mucosa, regulate immune system and activate glial cells in the brain
What is the phosphate buffer system?
H+ + HPO42- <--> H2PO4- Part of renal regulatory mechanism
What is the blood supply to the retina and how does this explain glaucoma?
Has inner and outer blood supply. Inner retina (ganglion and bipolar cells) supplied by central retinal artery and outer retina supplied by choroid capillaries from ciliary arteries (branches of ophthalmic artery). Glaucoma kills photoreceptor cells as the pressure squashes ciliary arteries in choroid so prevents O2 delivery to cells
Describe the flow characteristics of synovial fluid and how does H2O move when the joint is compressed/relaxed?
Has non-Newtonian properties (viscosity isn't constant). At rest it becomes thicker (rheopectic) and becomes less viscous with movement (thixotropic). When joint is compressed, H2O forced out of cartilage and moves back into cartilage when joint is relaxed to concentrate the HA
What is the structure of a rod?
Has outer segment that contains many stacked discs to increase chance of photon interacting with photopigment rhodopsin
What is the structure of the cochlea?
Has scala tympani and scala vestibuli (canals filled with periplymph (similar to ECF)) and scala media (filled with endolymph (similar to ICF) next to organ of Corti
What do the mesencephalon and rombencephalon give off?
Mesencephalon gives off midbrain Rombencephalon gives off pons, cerebellum and medulla oblongata
What is IBS, what are upper and lower GI FGIDs and how are they diagnosed?
IBS is a range of GI diseases with unknown pathophysiology but a defined set of symptoms. Upper FGID - GORD, functioanl dyspepsia, bloating and pain Lower FGID - abdo pain, cramping, constipation and diarrhoea Diagnosed using ROME IV questionnaire after excluding biological causes
What do the ICA and vertebral arteries supply?
ICA supplies anterior 2/3 of cortex and vertebral arteries supply posterior 1/3 of cortex, brainstem and spinal cord
How is Parkinson's treated?
L-dopa with aromatic AA decarboxylase inhibitor (can't cross BBB) so only converted to dopamine in the brain Also treated with dopamine receptor agonists
What are the different types of Ca channels, how are vesicles opened and where are Ca channels found in NMJ?
L-type (heart and vascular smooth muscle) and N-type (pre-synaptic terminals and mediate NT release) Synaptotagmin senses/binds Ca and causes SNAP to pull vesicle open at membrane Ca channels found close to vesicles
What are the venous great vessels?
L/R brachiocephalic veins, L/R subclavian, L/R internal jugular and SVC
How does endochondral ossification occur?
Mesenchymal stem cells differentiate into chondroblasts --> chondroblasts secrete hyaline cartilage and collagen type II --> become encased in matrix to form chondrocytes --> central chondrocytes hypertrophy and release alkaline phosphatase that trigger calcification --> central chondrocytes die and leave a cavity for osteoblasts to move into --> nutrient artery penetrates perichondrium via nutrient foramen and picks up osteoprogenitor cells --> carries in osteogenic cells --> 1y ossification centre deposits bone matrix using osteoblasts --> osteoclasts remove bone and form medullary cavity that fills with red bone marrow --> blood vessels grow into epiphyses to form 2y ossification centre
How is dopamine made?
Monoamine made by L-tyrosine --> L-Dopa --(aromatic AA decarboxylase)--> dopamine
Describe NACHR receptors
NACHR receptors need 2x ACH to bind and is permeable to both Na and K (only Na normally moves due to conc gradients) to produce EPP or EPSP.
How do you calculate net filtration pressure (NFP)?
NFP = (HPc - HPif) - (OPc - OPif)
What is NH3 converted to and why?
NH3 is converted to urea as it is less reactive and more soluble
What are the inputs to RF for control of breathing?
NTS inputs from vagal lung mechanoreceptors and CNIX arterial chemoreceptor (detect blood pO2) afferents. Also input from chemoreceptors of 4th ventricle that monitor CSF pH
How do you name benign tumours?
Name of cell origin + morphological character + -oma. Glandular epithelia form adenomas and stratified squamous epithelia forms papilloma
What is c-MYC?
Promotes cyclin (transcription factor) production. c-MYC overexpression alone can't cause tumorigenesis
What are NANC receptors?
Non-adrenergic, non-cholinergic receptors. Use other NTs (neuropeptides, nitric oxide, serotonin, ATP) and mostly found in peripheral tissues
What causes hydrocephalus, how is it detected and how is it repaired?
Obstructed CSF circulation usually from blocked cerebral aqueduct Translucent skull as no brain matter to block light Repaired by shunt (inserted into 3rd ventricle into subarachnoid space)
What is peripheral vascular disease and what causes it?
Occlusive disease of arteries in lower extremity caused by emboli, atherosclerosis, arteritis or aneurysm
Where do the oculomotor, trochlear and abducent nerves emerge and where do they enter?
Oculomotor emerges from midbrain, trochlear emerges from posterior midbrain and abducent emerges from pons. All enter orbit via superior orbital fissure
How is phosphocreatine formed and what is its role?
PC from transfer of phosphate from ATP using creatine kinase. Found in high, fluctuating energy demand tissues (muscle and brain) and acts as ATP buffer
Where does PCL run, what does it prevent and what is a physical property?
PCL runs from posterior part of tibia to attach to medial part of femoral intercondylar fossa to prevent posterior movement of tibia. Stronger than ACL
When is PDC active and inactive and how is it controlled?
PDC is controlled by feedback inhibition (high levels of acetyl CoA and NADH inhibit PDC). Active when dephosphorylated and is activated/phosphorylated by PDH kinase and PKA
What are the 3 paired salivary glands, what innervtaes them and where do they drain?
Parotid, sublingual and submandibular glands. Parotid glands innervated by glossopharyngeal nerve and drains into parotid duct to enter mouth at level of upper 2nd molar. Sublingual and submandibular glands innervated by facial nerve and drain into mouth either side of frenulum of tongue
Describe NK cells
Part of innate immune system but are lymphocytes. Don't have antigen-specific receptors and can kill when resting, but more effective when activated by cytokines
How do you calculate partial pressure and what is ppO2 of dry inspired air?
Partial pressure = total pressure in gas mixture x fractional concentration. ppO2 is 160mmHg or 21kPa
What do radius and ulna articulate with, what is the function of the ulna, where is the radial tuberosity found, what is the olecrannon process and where does this move when the elbow extends?
Radius articulates with capitulum (spherical condyle) and ulna articulates with trochlea (pulley condyle). Ulna has a function in stabilising the arm and large proximal end specialised for articulation. Radial tuberosity (attachment for biceps brachii tendon) found below radial neck. Olecrannon process is the bony part at the back of the elbow (from ulna) and moves into olecrannon fossa in humerus when elbow extends
How do rapidly and slowly adapting receptors respond to stimuli?
Rapidly adapting receptors only respond at beginning of stimulus and fatigue quickly. Slowly adapting receptors continue firing to sustained stimulus but at gradually reducing rate
What are the mechanisms of tachphylaxis and tolerance?
Receptor desensitisation, receptor internalisation, increase in receptors in antagonists, exhaustion of receptors or increased metabolic degradation
What is degeneracy?
Same AA coded for by different codons. Gives some protection against mutation of 3rd base (silent)
What is the sarcolemma and intercalated discs and what makes up intercalated discs?
Sarcolemma is plasma membrane of muscle fibres and intercalated discs are thickened portions of sarcolemma. Made from gap junctions (facilitate electrical communication and passage of ions/APs from cell to cell), desmosomes (hold cells together to connect cells during contraction) and anchoring junctions (attach sarcomeres to cell membrane)
What are the different types of glial cells?
Satellite cells - support cell bodies Schwann cells - produce myelin sheath (PNS) Oligodendrocytes - produce myelin sheath (CNS) Microglial cells - modified immune cells in CNS Astrocytes - form BBB and support CNS Ependymal cells - line ventricles
What bone is in the anatomical snuff box and what are it's borders?
Scaphoid Borders - extensor pollicis longus (medial) and extensor pollicis brevis and abductor pollicis longus (lateral)
What is in the anatomical snuff box, what joints are found in the thumb and what movements do they allow?
Scaphoid bone found in anatomical snuff box. Thumb has metacarpophalangeal joint and interphalangeal joint that allow flexion (move across palm)/extension, abduction (away from palm at right angle)/adduction and opposition (combination of flexion, abduction and medial rotation)
What movements does scapulothoracic articulation allow and what proportions of arm movement come from which areas of the shoulder joint?
Scapulothoracic articulation allows elevation/depression, protrusion/retraction and rotation. 2/3 of arm movement comes from GH joint and 1/3 comes form scapula
How does a damaged axon in PNS regenerate?
Schwann cells divide and release trophic factors to guide axon, they remyelinate new axon. Peripheral nerves regenerate at around 1mm/day
What causes sciatic nerve injury and what does this cause?
Sciatic nerve injury caused by posterior hip dislocation and causes foot drop, hamstring, calf muscle and dorsiflexor wasting and loss of Achilles reflex
What are drugs and what are their roles?
Substances that interact with regulatory molecules to activate/inhibit body processes
What is the function of depolarising NMJ blockers, give an example and how do they work?
Succinylcholine stimulates ACH receptors and activate muscle but don't detach. Muscle unable to initiate depolarisation after first as receptor desensitised to ACH First opening of Na channel causes fasciculations
Describe the post-absorptive phase of carbohydrate digestion
Sugar exits cell across basolateral membrane by facilitated diffusion into portal vein
What molecules form DNA and where are new nucleotides added?
Sugar-phosphate backbone and organic base (ATCG). Added from 5' to 3' during replication
What muscles are the superficial flexors of the hand and what other muscle in the posterior compartment of the arm is used for wrist flexion?
Superficial flexors are flexor carpi radialis/ulnaris, palmaris longus and pronator teres. Brachioradialis in posterior compartment of arm also used for wrist flexion
What is the transverse mesocolon and mesentery?
Transverse mesocolon attaches transverse colon to posterior abdominal wall. Mesentery connects small intestine to posterior abdominal wall and provides pathway for SMA
Give 3 examples of causes of uncoupling in the ETC
Thermogenin (uncoupling-protein 1) in brown adipose tissue uses proton gradient for non-shivering thermogenesis. Some antibiotics (gramicidin - forms two half channels, nigericin - enables H+ to permeate membrane and valinomycin - enables charge dissipation through K movement). Dinitrophenol can cross mitochondrial membrane then release H+ to uncouple ETC (uncoupling releases heat)
How does the hypothalamus control thermoregulation?
Thermoreceptors in anterior nucleus of hypothalamus of cutaneous thermoreceptors detect temperature Heat loss - inactivity, vasodilation, sweating Heat gain - shivering, vasoconstriction, piloerection, stop sweat secretion
Why must mitochondria be considered for antibiotics?
They have transcription/translation mechanisms similar to those in proteobacteria
How are the LA and LV different to the right side?
Thicker myocardium on left side and smoother muscle
What are treatment methods for peptic ulcer disease and what is triple therapy?
Treated using vagotomy (reduces ACH secretion to reduce acid secretion), H2RAs (cimetidine, ranitidine, famotidine that block H2 receptors on parietal cells to reduce acid secretion), PPIs (eg. omeprazole that inhibits H+/K ATPase on parietal cells) and antibiotics (amoxicillin + clarithromycin to kill H pylori) Triple therapy is amoxicillin + clarithromycin + PPI
What comes from thoracic and abdominal aorta?
Thoracic (ends at T12) - intercostal arteries. Abdominal - coeliac (T12 and supplies foregut), renal (L1/L2), superior mesenteric (L1 and supplies midgut) and inferior mesenteric (L3 and supplies hindgut)
Where does the cephalic vein run and what gives a curve to the shoulder and neck?
Through deltopectoral groove and drains into axillary vein Trapezius gives neck curve and deltoid gives shoudler curve
What are the structures found anterior to posterior in superior mediastinum?
Thymus, veins (brachiocephalic and SVC), phrenic nerves, arteries, vagus and recurrent laryngeals, trachea, oesophagus and thoracic duct
What are the branches of the sciatic nerve, how do they travel, where does the small saphenous vein drain, what gives rise to sural nerve and what does it do?
Tibial (runs straight down) and common peroneal (travels laterally) nerves. Small saphenous vein drains into popliteal vein. Tibial and common peroneal nerves give rise to sural nerve (sensory innervation to lateral leg)
What is CT image based on and how does acute haemorrhage show on CT?
Tissue density Acute haemorrhage is white
How can prodrugs be used in cancer?
Toxic drug given as prodrug which is converted to cytotoxic form that activates suicide cascade of cancer cell
Describe the trachea and oesophagus
Trachea (C6-T4) has cartilaginous U shaped rings with carina at T4/T5 where aorta arches over left main bronchus. Oesophagus (C6-T10) immediately posterior to trachea but inclines left and is compressed by aortic arch (T4) and left lung root (T5-T6)
What is used to monitor neuromuscular blockade and what do the measurements show?
Train of four (ToF) - ratio of height of 4th response to 1st response Ratio 0.15-0.25 is adequate surgical relaxation and >0.9 needed for complete recovery
What is p53 and how can it cause cancer?
Transcription factor activated by hypoxia, DNA damage or cell injury. Activates p21 (CDKI) --> inhibits cyclins --> prevents G1/S transition to allow DNA repair/apoptosis
What is Edwards syndrome?
Trisomy 18, 1 in 3000 births and causes malformation of heart, kidneys and clenched hands
What is the role of the vincula in the fingers and what do the thenar and hypothenar muscles do?
Vincula helps to anchor the flexor tendons to finger bones to limit movement away from the bone. Thenar muscles flex the thumb and hypothenar muscles flex the little finger
Describe the enzymatic processes involved in glutamate metabolism in the liver
a-ketoglutarate <--> glutamate <--> glutamine Glutamate + NAD <--(glutamate dehydrogenase)--> a-ketoglutarate + NH3 + NADH Glutamate + NH3 --(glutamine synthetase)--> glutamine Glutamine --(glutaminase)--> glutamate + NH3
What does preload determine and how do you calculate SV?
Preload determines EDV which determines stroke volume. SV = EDV - ESV
Where do the ulnar and median nerves run?
Ulnar - behind medial epicondyle of humerus Median - with brachial artery
How is airway resistance measured and what does it vary with?
Using peak flow meter and varies with gender and height
What is the mechanism of glycogen breakdown from adrenaline and glucagon and how does insulin affect this?
"Adrenaline and glucagon activate GPCR --> activates adenylyl cyclase --> increases cytosolic cAMP --> activates protein kinase A --> protein kinase A activates phosphorylase kinase --> phosphorylates glycogen phosphorylase --> stimulates glycogen breakdown. Insulin binds to insulin receptor --> activates phosphodiesterase --> stimulates breakdown of cAMP --> decreased glycogen phosphorylase activity
Where are the 1y motor, 1y somatosensory, 1y auditory, Broca's/Wernicke's areas and 1y visual cortexes found?
1y motor - pre-central gyrus 1y somatosensory - post-central gyrus 1y auditory - superior part of temporal lobe Broca's area - frontal lobe Wernicke's area - behind 1y auditory centre 1y visual cortex - base of occipital lobe
Where are the 1y visual and auditory cortexes found and what are Broca's and Wernicke's areas?
1y visual cortex found at back of occipital lobe and auditory cortex found at top of temporal lobe. Broca's area (motor language) and Wernicke's area (sensory language) found on one side of brain (mostly left)
What is the structure of basophils and what do they contain?
2-3 lobed nucleus and dark blue staining granules containing histamine
What is the structure of neutrophils and when are they increased/decreased?
2-4 lobed nucleus, neutral staining granules. Increased in infection/inflammation, tissue damage and haemorrhage. Decreased in HIV, sepsis, bone marrow failure, medications or B12/folate deficiency
How does an AP cause ACH release at NMJ?
AP in motor neuron axon reaches terminal bouton --> Ca VGCs open --> Ca influx --> docked vesicles fuse with pre-synaptic membrane --> contents released into synaptic cleft
How is the AP different in smooth muscle compared to skeletal muscle?
AP lasts much longer in smooth muscle and is mostly dependent on Ca. Ca channels open much slower so longer upstroke
What is the mechanism of IgE-mediated hypersensitivity and what do mast cell mediators cause?
APC processes antigen --> MHC-II presents antigen to naïve T cell --> promotes Th2 development --> Th2 releases IL-4 and IL-13 --> B cells produce IgE --> IgE binds to mast cells --> mast cells become sensitised --> second exposure to allergen causes IgE cross-linking and mast cell degranulation --> mast cell mediator (eg. histamine) release --> airway limitation by bronchoconstriction and mucus hypersecretion
How is ATP produced and how does it release energy?
ATP made from phosphorylation of ADP or AMP and is adenine and ribose (adenosine) with phosphate groups. Energy released on hydrolysis from repulsion of negative groups and increased resonance when phosphate separate
Where is vitamin B1 absorbed and what can deficiency cause?
Absorbed in jejunum and involved in TCA cycle and glycolysis. Causes Beri Beri disease Wet Beri Beri - tachycardia, enlarged heart, peripheral oedema Dry Beri Beri - symmetric peripheral neuropathy Shoshin Beri Beri - cardiac failure and lactic acidosis
What are the roles of accessory ligaments and menisci in synovial joints?
Accessory ligaments - connect bone to bone and hold the joint together Menisci - modify shape of joint surfaces, maintain stability and direct synovial fluid to areas of greater friction
How is alanine metabolised in the liver?
Alanine transported to liver where it is converted to pyruvate, reforming glutamate (feeds into urea cycle) from a-ketoglutarate. Pyruvate converted to glucose which is transported to muscle
What are the acetabulum, acetabular labrum, transverse ligament and where do blood vessels pass into joint through?
Acetabulum is deep cup in pelvis formed by 3 bones. Acetabular labrum forms horseshoe shaped rim of fibrocartilage around the joint. Transverse ligaments bridges acetabular notch and increases articular capsule SA. Blood vessels pass through acetabular notch or via ligament of head of femur
What are histone tail modifications?
Acetylation, phosphorylation, methylation. Most modifications on lysine. Histone acetylase (HAT) opens DNA and histone deacetylase (HDAC) closes DNA
What is the protein buffer system?
Acidic/basic side chains of AAs can give/take up H+ to solution
What are sulphonamides?
Act as competitive inhibitors of folic acid synthesis enzymes. Co-trimoxazole
What can be made from omega-6 and omega-3?
Acted on by elongases and desaturases to form arachidonic acid (from omega-6) and eicosapentaenoic acid (from omega-3). Can form paracrines (leukotrienes, thromboxanes, prostaglandins) by Cox-2. Cox-2 inhibition by NSAIDs (ibuprofen, aspirin and indomethicin) can reduce inflammation, fever and pain
What are the mechanisms that cause a rise in intracellular Ca for smooth muscle contraction?
Actiavtion of LTCC by membrane depolarisation or agonist binding that triggers intracellular Ca release via IP3
How does cell migration occur?
Actin filament polymerisation at leading edge gives protrusive force and new adhesions rapidly linked to actin network. Retrogade actin movement and contractile force from stress fibres produces tension and pulls cell body forward. Contraction causes retraction of trailing edge
What are microfilaments?
Actin microfilaments important in cell movement with myosin (muscle movement)
What role does Ca2+ have in synaptic tranmission?
Action potential causes Ca2+ release and SNARE complex anchors vesicle to cytoskeleton. Ca2+ binds to vesicles and allows release of NT
How do orofacial muscles contribute to feeding behaviour?
Actions during drinking/eating activaate dopamine neurons in VTA which projects to nucleus accumbens to cause feelings of pleasure/reward
What is the auditory attenuation reflex?
Activated by own voice/loud sounds to dampen out low frequency sound and allow better speech understanding
How are encapsulated endings activated, how does this happen and what does depolarisation cause?
Activated by physical distortion of teminal membrane which opens mechanically sensitive Na channels to cause influx and depolarisation when axon is bent Depolarisation causes receptor potential (graded potential)
What activates pain, what is normal pain, what are the components of pain and how can normal pain be treated?
Activated by tissue damage detected by nociceptors. Normal pain is pain caused by nociceptor activity and requires tissue-damaging stimulus. Pain has acute (fast pain mediated by Ad nociceptors) and chronic (slow pain/aches mediated by C nociceptors). Treated with opiates, NSAIDs or steroids
What does subfornical organ osmoreceptor stimulation cause?
Activates cells in medial preoptic nucleus of hypothalamus which projects to limbic system to regulate sense of thirst. Activation creates sense of thirst and will seek out water and also activates paraventricular and supraoptic nuclei to cause ADH release from posterior pituitary
What are the types of transport across a cell membrane?
Active (against conc grad using ATP energy) or passive (no energy required and down conc grad). Uniports move 1 molecule, symport moves 2 molecules in same direction and antiport moves 2 molecules in opposite direction. 2y active when conc of one ion moves other ion
What is somatostatin, where is it released from, what does it act on and what are D cells?
Acts as a brake on acid production. Released from D cells (detect [H+] and high [H] causes somatostatin release). Acts on somatostatin receptors on parietal and ECL cells via paracrine or endocrine signalling
What are the functions of the brainstem?
Acts as conduit to/from spinal cord, sensorimotor integration, integrative centre and mediation of autonomic control and somatic/autonomic modulation
What is the function of the nucleus pulposus and what happens when compressed/stretched?
Acts as shock absorber. Becomes broader when compressed and thinner when stretched
How is adrenaline used for anaphylaxis?
Acts on alpha 1 receptors (smooth muscle contraction), alpha 2 receptors (smooth muscle contraction) and beta receptors (heart muscle contraction and smooth muscle relaxation) to cause bronchodilation and peripheral vasoconstriction
Describe the process of b-oxidation
Add CoA to FA --> produce FADH using acyl CoA dehydrogenase --> add H2O using enoyl CoA hydratase --> produce NADH using 3-OH acyl CoA dehydrogenase --> 3-ketoacyl CoA thiolase produces acetyl CoA Each enzyme has different isoforms with differing chain length preferences
What is DNA methylation and consequences of abnormal hypermethylation?
Addition of methyl groups to cytosine of DNA in CpG islands of promoter using DNA methyltransferase prevents transcription by preventing transcription activator binding. Abnormal hypermethylation of tumor suppressor genes and hypomethylation of repetitive regions can cause cancer
Explain signalling by phosphyorylation
Addition of phosphate by kinase and removal by phosphatase. Can activate/deactivate protein
How are biofilms produced and why?
Adhesion --> monolayer formation and slime --> microcolony formation --> mature biofilm. Protects bacteria from host attack and removal
What is the impact of insulin in adipocytes, liver cells and what are the other functions of insulin in cells?
Adipocytes - inhibits lipolysis and stimulates lipogenesis Liver - enhances glucose uptake, inhibits gluconeogenesis, stimulates glycogen synthesis and stimulates lipogenesis Cells - promotes protein synthesis and storage, transport of AAs into cells, increases mRNA translation, inhibits protein catabolism and promotes K intracellular uptake
What NT acts on beta receptors, what are they types of beta receptors and drugs that act on them?
Adrenaline. B1 - increases myocardial force and contractility. B2 - bronchial smooth muscle relaxation. B3 - gluconeogenesis and lipolysis. B1 antagonist (bisoprolol) for stressed/hypertensive pts. B2 agonist (SABA - salbutamol, fenoterol, LABA - clenbuterol, salmeterol
How do adult and foetal/newborn Hb differ and why is this useful?
Adult has 2x alpha and 2x beta subunits. Foetal has 2x alpha and 2x gamma subunits. Foetal Hb has a higher affinity for O2 than adult so can remove O2 from placental blood
What are the advantages/disadvantages of x-rays?
Advantages - cheap, readily available. Disadvantages - ionising radiation, gives 2D image, doesn't show soft tissue well, structures behind obscured, processes inside bone not seen
What are the advantages and disadvantages of CT imaging?
Advantages - images in transverse plane, high contrast bone detail, well tolerated, readily available Disadvantages - ionising radiaiton, metallic artefacts, respiratory artefact, soft tissue around bone difficult to image
What are the advantages and disadvantages of endoscopy?
Advantages - macroscopic real time view, obtain hisology, visualise entire bowel, therapeutics Disadvantages - sedation, technically demanding, complications, limited to luminal views
Advantages/disadvantages of CT?
Advantages - more detail than x-rays, give 3D image, high contrast bone detail and readily available. Disadvantages - lots of ionising radiation, metal artefacts, respiratory movement artefacts, soft tissue surrounded by bone hard to image
What are the advantages and disadvantages of MRI?
Advantages - non-ionising radiaiton, very good soft tissue contrast, images in transverse plane Disadvantages - doesn't image bone directly
What are the advantages of USS, what procedures is it useful for and what is doppler?
Advantages - quick, readily available, accurrate, real-time visualisation Useful for nerve block, aspiration, steroid injection Doppler uses USS to measure blood flow in vessels
What is X-linked recessive inheritance?
Affected males born to unaffected parents and carrier mother. Affects mainly males and sons unaffected but daughters carriers. No male-to-male transmission, but female carriers have 50% chance of affected son
How does stopping/starting drug affect other drugs bound to albumen?
Affects the amount of other drugs bound. Eg. phenytoin and warfarin - if warfarin stopped for surgery, more phenytoin binds to albumin so sub-therapeutic levels of free phenytoin
What factors can influence drug metabolism?
Age (biotransformation slower in children and elderly), gender (women have less oxidation of ethanol, benzodiazepines, salicylates and oestrogens), ethnicity (7-8% Caucasians and 1% Asians have inactive P450 2D6 but hyperactive in 30% East Africans), diet and environment and liver/kidney disease
What are sympathomimetics?
Agents that produce effects similar to NE/EPI
How does aggrecan change with age and how does this cause osteoarthritis?
Aggrecan amount and complexity decreases with age Young - bigger and longer complexes (attracts more H2O) Old - smaller and fewer side branches (attracts less H2O) OA caused by loss of complexity of aggrecan
What are the aims of faecal microbiotal transfers and what are the donor sources?
Aims to increase gut microbial diversity. Donor sources are healthy relatives, 'super donors' and artificially produced probiotics
What are the paranasal sinuses, where are they found, what are their functions and where do they drain?
Air-filled extensions of the nasal cavity. Frontal (above eyes in forehead), ethmoid (top of nose), sphenoid and maxillary (cheeks) cavities. Functions are reduce weight of skull, vocal resonance and crumple zone. Maxillary and frontal sinuses drain into middle meatus
What are A and B in CXR interpretation?
Airway - are trachea and bronchi visible, does trachea pass down RHS of aorta. Breathing - lung markings occupy entire field to thoracic wall, pleura and pleural spaces only visible in abnormality
What are the airway bronchodilator nerves, what is the main NT and where is NOS expressed?
Airway bronchodilator nerves are NANC mediated by NO NT. NOS (NO synthase) expressed in epithelial and nerve cells
How is the V/Q ratio affected in airway obstruction and blood flow obstruction and why?
Airway obstruction causes a decreased V/Q ratio as there is less ventilation. Blood flow obstruction causes increased V/Q ratio as less perfusion
What is all-or-nothing and what is threshold?
All action potentials are always the same size. Threshold is reached when opening Na+ VGCs stimulate opening of more Na+ VGCs in +ve feedback loop
What cell do osteoprogenitors, osteoblasts and osteocytes come from, what do each of them do and what are lining cells?
All come from mesechymal progenitors. Osteoprogenitors are bone stem cells (in peri/endosteum). Osteoblasts are bone makers that produce osteoid (organic matrix). Osteocytes are bone maintainers that sense the state of the bone matrix. Lining cells are old osteoblasts not encased in matrix and they regulate Ca entry in/out of bone
What innervates muscles of mastication, what are the muscles of mastication and what do each of them do?
All innervated by mandibular branch of trigeminal nerve. Temporalis, masseter (from mandibular angle to zygomatic) and medial/lateral pterygoids (attach to pterygoid plates of sphenoid) All for elevation apart from lateral pterygoid and all for protrusion apart from temporalis.
What makes up the PNS and what is it's function?
All peripheral nerves and CNs. Sensing and relaying info to/from CNS
How can drugs interact with receptors without binding directly?
Allosteric interaction of drug can affect efficacy and potency of ligands. Activators increase receptor activation and inhibitors decrease receptor activity
What are the methods of control of regulatory enzymes?
Allostery (modifier binds and changes 3D conformation), covalent modification (addition/removal of phosphate group by another enzyme, short term) and protein synthesis (hormones control expression of enzyme protein)
What are arachnoid granulations?
Allow CSF to flow into venous blood of sinuses but prevents backflow of blood into subarachnoid space
What is the function of the intestinal epithelial barrier and what modulates the IEB regulation?
Allow absorption of nutrients but control passage of pathogens and toxins. IEB regulation modulated by outer (microflora and chyme) and inner (immune cells, fibroblasts or ENS and extrinsic nerve fibres) microenvironments
What movements do planar joints allow and where are they found?
Allow side-side or back and forth gliding movements. Found in intercarpals/intertarsals and facet joints of vertebral column
What do complex metabolic pathways allow?
Allows efficient energy capture and control whilst branches enable links to related pathways and different outputs
What are the different adrenergic receptors?
Alpha 1 (smooth muscle contraction) and 2 (NT release inhibition) and beta 1 (cardiac muscle contraction), 2 (smooth muscle relaxation) and 3 (glycogenolysis)
What is the 2y structure?
Alpha helix - R groups point out but proline can't exist due to cyclic structure. Stabilised by H bonds between peptide bonds. Beta pleated sheet - H bonds between amide links and chains parallel or antiparallel. Disordered - interacts with other proteins
What is a motor unit and why is it significant?
Alpha motor neuron and all muscle fibres supplied by it When motor neuron fires all muscle fibres innervated by it will contract
What happens to adrenoreceptors during exercise?
Alpha receptors restrict flow to non-essential muscle. B1 increases HR, inotropy and CO. B2 causes bronchodilation to decrease airway resistance and increase O2 uptake. B3 causes lipolysis and glucose release from liver and uptake in active musles
What type of WBC is found in alveoli, what is their role, when are they reduced and what can this cause?
Alveolar macrophages that phagocytose invading bacteria. Reduced in HIV or radiotherapy and makes person vulnerable to bacterial/viral lung disease
What are pO2 and pCO2 in alveoli and in blood leaving the lungs?
Alveolar pO2 = 100mmHg and alveolar pCO2 = 42mmHg. Blood leaving lungs pO2 = 90mmHg and pCO2 = 40mmHg
What is alveolar ventilation, how is it calculated and how do gases move between air and blood?
Alveolar ventilation is the rate that new air reaches the alveoli to participate in gas exchange. Alveolar ventilation = (tidal volume - dead space) x respiratory rate. Gases move between air and blood using passive diffusion due to pressure differences
What is bacterial pneumonia and how does it impact gas exchange?
Alveoli are inflamed from bacterial toxins. Fluid leaks from capillaries into alveoli so decreases SA for gas exchange. Leucocytes enter alveoli and attack bacteria, causing pus to further reduce gas exchange
What can treat influenza?
Amantadine (prevents viral uncoating by blocking H+ entry into virion) or neuraminidase inhibitors to prevent release or virus particles
What are the methods of managing HT?
Amending modifiable factors (environment/lifestyle, salt and smoking) or pharmacotherapy (options that modulate pathways affecting BP)
What movements do the muscles in the anterior/posterior arm compartments do and what nerve innervates each compartment?
Anterior compartment (musculocutaneous nerve) causes flexion of shoulder and elbow and posterior compartment (radial nerve) causes extension
Where do the anterior and posterior pituitary develop?
Anterior develops in roof of mouth then migrates upwards Posterior develops from downward pouch of brain tissue and upper part remains connected to hypothalamus via pituitary stalk.
What is clonal expansion?
Antigen activates lymphocytes with specific receptor. Proliferates to create copies with identical receptor using IL-2. Some cells kept as memory cells for rapid, stronger response
What are antigens, immunogens and epitopes?
Antigens - anything that binds to receptor on immune cell, immunogens - things that cause immune response, epitopes - part of antigen that interacts with receptors on immune cell
Where does the aorta bifurcate, what does it form and where do the branches bifurcate and what do they form?
Aorta bifurcates at L4 into common ileac arteries which divide at S1 into external and internal (gives off superior/inferior gluteal arteries and obturator artery) ileac arteries
How are aortic arch and trachea bifurcation different when supine and standing?
Aortic arch - superior to transthoracic plane when supine but transected when standing. Trachea bifurcation - transected when supine but inferior when standing
Describe the blood leaving the apex and base of lungs and the overall composition of pulmonary venous blood
Apex has a smaller volume of blood with high pO2 and low pCO2 but base has a large volume of blood with lower pO2 and higher pCO2. Pulmonary venous blood is a mix between apical and basal blood
How is the V/Q different at the apex and base and does perfusion or ventilation change most with height?
Apex has greater V/Q (3.3) than base (0.6) as apex has ventilation > perfusion. Perfusion changes most with height
What are the types of cell death?
Apoptosis - controlled cell death (beneficial) and necrosis (detrimental, from trauma, high/low temp, snake/spider bites, oxidative stress)
What neurons in the hypothalamus affect feeding bahaviour?
Arcuate and periventricular nuclei contain neurons that have receptors for gut hormones to control feeding behaviour Hunger - agouti-related peptide (AGRP) and neuropeptide Y (NPY) Satiety - cocaine and amphetamine related transcript (CART) and pro-opiomelanocortin (POMC)
What hypothalamic nuclei act on the anterior pituitary?
Arcuate, suprachiasmatic and preoptic nuclei axons end on capillaries in portal system to secrete releasing hormones that pass down capillaries and are released on cells of anterior pituitary
How do metabotropic glutamate receptors work and what are the types of 2nd messengers?
Are GPCRs and 2nd messenger transmit and amplify signals from receptor to downstream target molecule. Can be soluble hydrophilic (cAMP, cGMP, Ca2+), non-soluble hydrophobic (DAG and PIP3) or gases (NO, CO, ROS)
How do kidneys regulate acid-base balance and what is normal HCO3?
Are long term regulators and excrete or conserve H+ and HCO3-. Normal HCO3 - 22-26mEq/L
Which areas occupy largest areas of cortical map, which areas have the highest touch receptor density and what is cortical map plasticity?
Areas with highest density of touch and proprioceptive receptors. Skin, tongue and lipds have highest density. Cortical map plasticity where if part of body removed the area in brain is redistributed to other body parts
How do cancer cells appear and how can telomerases increase cancer risk?
Arise from mutations in SCs or differentiated cells. High levels of SC telomerase increase proliferation efficiency and increased cancer risk
What parts are found in arteries, veins and capillaries?
Arteries - thicker media for elastic recoil, capillaries - only intima for rapid diffusion, veins have thinner media and thicker adventitia with valves
How are ICAs and basilar artery and CN V seen on axial MR?
Arteries visible and black with CN V visible emerging from brainstem
What are the vessels that pass in/out of capillaries?
Arterioles (endothelium, muscular wall and sympathetic nerves) --> terminal arterioles (smooth muscle, few nerves) --> capillaries --> venules
What is an arthrogram and what can DEXA scans be used for?
Arthrogram - iodine contrast media injected into joint plus air to visualise joint space and bursa DEXA scans used for diagnosis of osteoporosis and body composition
What forms articular cartilage and the epiphyseal growth plates?
Articular cartilage formed by hyaline cartilage at the end of the epiphyses. Epiphyseal growth plates formed by hyaline cartilage between diaphysis and epiphysis
What are the neurovascular properties of articular cartilage, how does synovial fluid supply chondrocytes and what does articular cartilage contain?
Articular cartilage is avascular and aneural. Synovial fluid diffuses through chondrocytes to supply nutrients. Articular cartilage contains hyaline cartilage (collagen type II) and proteoglycans (form a hydrated gel)
What are the intrinsic laryngeal muscles and what do they do?
Arytenoid, cricoarytenoid and thyroarytenoid muscles are for phonation as they change the shape of the rima glottidis. Cricothyroid muscle changes pitch
What are the timings of impulse conduction in the heart and why are they important?
Atrial depolarisation 60ms after SAN depolarisation. AVN holds impulse for 60ms then ventricle depolarisation 120ms after SAN depolarisation. Allows time for atria to push blood into ventricles
What are non-selective muscarinic antagonist examples?
Atropine - reduces bronchial secretions, mydriasis, treats bradycardia and used in organophosphate poisoning. Scopolamine used as GI ansispasmodic for motion sickness. Ipratropium for asthma (bronchodilator)
How do osteoclasts break down bone?
Attach to bone and form a leak-proof seal --> secrete protein-digesting enzymes and HCL that break down collagen and dissolve calcium hydroxyapatite --> bone proteins and minerals (mainly Ca) transported across osteoclast into ISF --> move off to new area and osteoblasts fill lacuna with osteoid --> osteoid mineralises in 7-10 days
Where do deep muscles of back/paraspinals attach, what are they involved in and what is their innervation?
Attach to individual vertebrae and involved in posture and movement of vertebral column. Innervated by dorsal rami of spinal nerves
Where does the external oblique aponeurosis attach, what is the free inferior border called, what structures pass inferior to inguinal ligament, what forms the inguinal canal and what passes through this in males?
Attaches at superior iliac spine and pubic tubercle. Free inferior border is called inguinal ligament and femoral artery, vein and nerve pass inferior to ligament. Inguinal canal formed where aponeurosis folds in itself and spermatic cord passes through in males
Where does AA attach to tRNA and what enzyme does this use?
Attaches to 3' end of tRNA using amino acid acyltransferase enzyme.
What is the effect of botulinum toxin and what is it used to treat?
Attacks SNAP complex to prevent ACH release Used to treat spasticity/increased muscle tone (due to stroke, cerebral palsy, MS), headaches, sweating and cosmetic use
What is self cell signalling?
Autocrine cell signalling where cells secrete hormones/ligands that bind to autocrine receptors on same type of cell
What is myasthenia gravis, what does it cause and how is it treated?
Autoimmune disorder where antibodies attack ACH receptors at NMJ so EPP not large enough to trigger muscle AP Causes muscle weakness and fatigue and treated with ACHE inhibitor
What is coeliac disease, how is it diagnosed and what is the treatment?
Autoimmune response to gluten. Diagnosed using duodenal biopsy (shows villous atrophy, crypt hyperplasia) and serology (IgA anti-tTG and anti-endomysial). Treated is life-long, gluten-free diet
What are the divisions of the PNS and what are their functions?
Autonomic (unconscious actions such as breathing and control of HR) and somatic (conscious control of skeletal muscles)
What is the ENS, what are the roles of the submucosal and myenteric plexi and what is GALT?
Autonomous functioning ganglia with inputs from SNS, PNS and spinal sensory afferents. Submucosal plexus innervates muscularis mucosae and mucosal glands and myenteric plexus innervates muscularis propria. GALT is intraepithelial lymphocytes, plasma cells of lamina propria for IgA production and lymphoid follicles
What is average 24hr urine osmolality, random urine osmolality and urine osmolality after 12-14hrs of fluid intake restriction?
Average 24hr osmolality is 500-800mOsm/Kg. Random urine osmolality is 50-1400mOsm/Kg and urine osmolality after 12-14hr should be >800mOsm/Kg
What sensory innervation do the axillary, musculocutaneous, median, ulnar and radial nerves give?
Axillary - skin over deltoid Musculocutaneous - lateral forearm Median - lateral and middle palmar digits and fingertips of dorsal lateral digits Ulnar - medial palmar/dorsal hand and digits Radial - lateral dorsum of hand
How is hypothalamus involved with ANS?
Axons from hypothalamus project to lateral medulla to activate SNS/PNS. Visual/auditory info detected by cortex --> sends message to hypothalamus --> activates autonomic centres in medulla --> medullary cells project down spinal cord to activate SNS
How does hypothalamus control body water balance?
Axons from paraventricular/supraoptic nuclei down to posterior pituitary to end as secretory terminals that release ADH that reduces water loss in urine
What are the types of synapses?
Axosecretory, axoaxonic, axodendritic, axoextracellular, axosomatic or axosynaptic
Where is bile secreted, what property does it have and chemical what does it contain?
Bile secreted by hepatocytes in caniliculi. Has detergent property and contains HCO3 to neutralise stomach acid
What is bilirubin, how is it transported, what can prevent bilirubin release and what is jaundice?
Bilirubin is a product of RBC breakdown in spleen (haem group converted --> bilirubin). Transported bound to albumin. Bilirubin release can be prevented by bile duct blockage and jaundice is yellowing of skin and sclera due to excess bilirubin. Jaundice has pre-hepatic, hepatic and post-hepatic causes
How are toxic proteins directly targeted at infected cells?
Bind non-specifically using integrin molecules, MHC-I and TCR then interact and microtubule-organising centre and Golgi precisely focus release of lytic granules
What are un-competitive inhibitors?
Bind to ES complex so prevent reaction completion. Effect increases by increasing [S] and reversed by decreasing [I]
What are competitive inhibitors?
Bind to active site and prevent entry of substrate. Can be reversible (by increasing [S]) or irreversible by bonding with side-chain groups (sarin and cyanide)
What are selective beta agonists?
B1 - dobutamine increases HR and contractility . B2 - salbutamol for asthma bronchodilation. B3 - solabegron for overactive bladder and glycogenolysis
What is MOA of beta blockers and what effects do they have?
B1 adrenoreceptor antagonists. Negatively chronotropic and inotropic, decrease BP and myocardial oxygen demand
How and where is vitamin B12 absorbed?
B12 absorbed in terminal ileum only when bound to stomach-derived intrinsic factor. Binds to haptocorrin in salivary glands then complexed with IF. Transported into portal circulation then transferred to transcobalamin II which serves as plasma transporter
Describe ball and socket joints, what movements do they allow and where are they found?
Ball-shaped surface fits into cup-like depression to allow flexion/extension, abduction/adduction, circumduction and rotation. Found in shoulder and hip
How are encapsulated endings formed and what are Pacinian corpuscles and Ruffini endings sensitive to?
Bare nerve growing into tissue releases cytokines that cause local connective tissue cells to form a capsule around it (acts as mechanical filter). Pacinian corpuscles sensitive to vibration and Ruffini endings sensitive to pressure
How is cardiovascular function controlled by RF?
Baroreceptor input (CN X) and chemosensory input on pO2 (CN IX) travel to NTS Output via vagus from dorsal motor nucleus and nAmb or sympathetic outputs mediate compensatory changes in cardiac function/peripheral vasculature
How are viruses named?
Based on associated disease (HIV, measles), cytopathology (cytomegalovirus), site of isolation (hepatitis, rhinovirus, adenovirus, enterovirus) and biochemical features (retroviruses)
What are glycolipids?
Based on ceramide and contain sugar head groups. Protect cell from hostile environment, for cell-cell contact and lipid raft generation
How are viruses classified?
Based on shape, type and form of nucleic acid, eveloped or naked, mode of replication and organisation of genome
What is the function of bile salts and where/how are they absorbed?
Bile salts enhance digestive action of lipases by breaking down fat globules into smaller droplets (emulsification). Most absorbed in ileum and recycled by liver using enterohepatic circulation
What are agonists and how do they work?
Bind to receptor by mimicking natural ligand. When ligand leaves receptor, receptor usually deactivated but some activated permanently by covalent change
What are antagonists, the different types and how do they affect maximal effect?
Bind to receptors and prevent activation. Competitive (don't affect maximal effect as increased [agonist] can outway) - bind to receptor site but don't activate so reduce agonist potency and non-competitive (decrease maximal effect) - bind to allosteric site and modulate receptor function so reduce agonist efficacy by producing partial signal.
What is rifampicin and when is it useful?
Binds to and inhibits bacterial RNA polymerase. Lipophilic so crosses BBB and used in tuberculous meningitis
How is vitamin B12 transported?
Binds to salivary haptocorrin --> transported to stomach where it combines with stomach-derived intrinsic factor --> transported to terminal ileum where absorbed --> transported in portal circulation and transferred to transcobalamin II --> degraded in lyososome to allow function
What appears black, dark grey, light grey, white and bright white on an X-ray?
Black - air. Dark grey - fat. Light grey - soft tissue. White - bone. Bright white - metal
How do CCBs work and what are the different types?
Block Ca entry to vascular smooth muscle so prevent vasoconstriction. Dihydropyridine (amlodipine) - mainly vasodilate and reduce SVR or non-dihydropyridine (diltiazem) - reduce HR and inotropy
What is the effect of conotoxins and how does ziconotide have its effect?
Block N-type Ca channels so no ACH released Ziconotide also blocks N-type Ca channels (related with algesia) so has analgesic action
How does moving blood prevent clot formation?
Blood moving over endothelium deflects polypeptides, releasing Ca2+ into endothelium and NO formation (anticoagulant) which stimulates cGMP formation (smooth muscle relaxation)
What is control of drinking linked to and how is it sensed?
Blood osmolarity detected by subfornical organ osmoreceptors in wall of 3rd ventricle. High osmolarity increases urge to drink
What is the arterial supply of the spinal cord?
Blood supply from anterior/posterior spinal arteries (branches of vertebral arteries). Vertebral arteries join to give off anterior spinal artery and each vertebral artery gives off one posterior spinal artery. Blood supply reinforced by radiculospinal arteries (from arteries of body wall)
What is the blood supply to the spinal cord?
Blood supply from anterior/posterior spinal arteries from vertebral arteries. Also great segmental medullary artery on left inserting at T9-T11 that reinforces circulation to 2/3 of spinal cord by fusing with anterior spinal
What controls blood volume and osmolarity?
Blood volume controlled by ADH, osmolarity controlled by aldosterone. ADH affects permeability of collecting duct and aldosterone affects permeability of distal convoluted tubule and Na+ reabsorption
How is blood volume regulated, where are these sensors found and what stimulates volume sensors?
Blood volume regulated by volume (LA and RA) and sodium receptors (kidney). Volume sensors stimulated by an increased venous return that causes increased stretch
What metabolic adaptations occur in hypoxic conditions, what is HIF and what does it do?
Body limits ATP use, improves anaerobic ATP production efficiency and limits oxidative stress. Metabolic adaptations driven by transcription factor hypoxia-induced factor 1. HIF1a subunit degraded by ubiquitination in normoxia but is stabilised in hypoxia where it binds to upstream elements of promotors (HREs). Also upregulates glycolytic and EPO genes
What is the effect of bodyweight distribution on muscle tone in different areas?
Bodyweight mostly anterior to vertebral column so antigravity muscles (eg. deep muscles of back) have to be more developed and have greater tone
What are the different processes of ossification?
Bone can develop by intramembranous (mainly in the skull where bone forms directly) or endochondral (everywhere else and uses cartilage precursor that converts to bone) ossification
Why is bone remodelling needed and what type of bone remodels quicker?
Bone remodelling needed for renewing bone before deterioration and redistributing bone matrix along lines of mechanical stress. Trabecular bone remodels quicker as it has a larger SA and responds to stresses faster
What are the borders of the antecubital fossa and what structures are found near/inside it?
Borders are lateral and medial epicondyles with brachioradialis (lateral) and pronator teres (medial). Superficial veins (cephalic and basilic) joined by median cubital vein in subcutaneous tissue. Also find bicipital aponeurosis (aponeurosis of biceps brachii tendon) and terminal part of brachial artery, brachial vein and median nerve
What movements do latissimus dorsi and teres major act together to allow?
Both act together to extend adduct and medially rotate
How do sympathetic and parasympathetic pre/postganglionic neurons work and what is the main function of PNS on the airway?
Both preganglionic release ACH. SNS postganglionic release NE and PNS releases ACH (onto M3). Main function of PNS is bronchconstriction
What arterial vessels split from aortic arch?
Brachiocephalic artery (forms R subclavian and R common carotid), L common carotid and L subclavian
What are the great vessels from the aorta and divisions of each?
Brachiocephalic trunk (divides into r subclavian (divides into r thyrocervical trunk, r vertebral and r internal thoracic) and r common carotid), L common carotid and L subclavian (divides into L thyrocervical trunk, L internal thoracic and L vertebral)
How much of the total resting CO do the brain, heart and kidneys require?
Brain - 14%, heart - 2%, kidneys - 25%
What makes up the CNS?
Brain and spinal cord (for higher functions like processing and interpreting info)
What is the arcuate fasciculus and what does damage to this cause?
Bundle of cortico-cortical association fibres that join Broca's/Wernicke's areas Damage to this causes conduction aphasia so impaired ability to repeat back heard/written words and difficulty reading aloud
What are bursa, what do they do in the knee and what is the most common knee bursa affected by bursitis?
Bursa are fluid-filled extensions of knee synovial cavity that act as cushions against friction and rubbing of tendon, ligaments and bones around knee. Prepatella bursa most commonly affected
What are bursa, what are those found in the elbow joint and what can cause bursitis?
Bursa are sacs of synovial fluid. Find deep and superficial olecrannon bursae and sometimes intratendinous olecranon bursa (inside triceps tendon). Bursitis caused by excessive pressure and friction (generally affects superficial bursa)
What are the types of fibres and what do they transmit?
C fibres (pain), Ad fibres (pain), Ab fibres (mechanoreceptors) and Aa fibres (motor neurons/proprioreceptors and fastest)
How does the complement system kill microbes?
C3b causes opsonisation, C5a enhances inflammation and C5b activates membrane attack complex which causes lysis
What are the types of T cells and how do they recognise foreign cells?
CD4+ (helper) and CD8+ (cytotoxic). Recognise linear antigens using TCRs and MHC of APC.
How does CF occur?
CF occurs through misfolding of CFTR protein so can't be transported to plasma membrane
Where do CN I, CN II, CNIII, CN IV and CN VI run?
CN I (olfactory) - runs from olfactory bulb through cribriform plate of ethmoid into nasal cavity CN II (optic) - runs through optic canal to enter orbit CN III (oculomotor), CN IV (trochlear) and CN VI (abducens) - run through superior orbital fissure to enter orbit"
What cranial nerves are main parasympathetic, what do they do and where do they come from?
CN III (from midbrain - eye smooth muscle), VII (from pons = salivary and lacrimal glands), IX (medulla oblongata - salivary glands) and X (95% of parasympathetic system)
What types of fibres do CN IX, X, XI and XII have and what are their functions?
CN IX - mixed (mainly sensory but also parasympathetic to parotid gland) CN X - mixed afferent and efferent with branchial motor innervation of palate CN XI - pure branchial motor to control neck and shoulder movements CN XII - somatic motor and innervates internal and external tongue muscles
What types of fibres do CN V, VII and VIII have and what are their functions?
CN V - pons mixed (branchial motor to muscles of mastication and general sensory) CN VII - pons mixed (mainlly branchial motor but also parasympathetic secretomotor and taste afferents) CN VIII - pons sensory for special sense of audition
Where do CN V1, V2 and V3 run?
CN V1 - runs through superior orbital fissure to enter orbit then exits via supraorbital foramen CN V2 - runs through foramen rotundum then exits via infraorbital foramen CN V3 - runs through foramen ovale then exits via mental foramen
Where does CNVII run?
CN VII (facial) - emerges from pons and passes through internal acoustic meatus then runs through petrous temporal bone and exits via stylomastoid foramen
Where do CN VIII, CN IX and CN X run?
CN VIII (vestibulocochlear) - emerges from pons and enters internal acoustic meatus CN IX (glossopharyngeal) and CN X (vagus) - emerge from lateral medulla and exit skull via jugular foramen
Where do CN XI and XII run?
CN XI (spinal accessory) - emerges then runs up foramen magnum then leaves via jugular foramen CN XII (hypoglossal) - emerges from anterior medulla then runs through hypoglossal canal
What structures are found in the posterior triangle?
CN XI, external jugular vein (runs superficially over SCM), lymph nodes, part of subclavian artery, brachial and cervical plexi and phrenic nerve
What makes up the CNS and PNS and what is the PNS divided into?
CNS made from brain and spinal cord. PNS made from spinal and cranial nerves and divided into visceral and somatic divisions
How do you calculate CO, how can SV and HR be measured
CO = SV x HR. HR measured using palpation or ECG and SV measured using echocardiography
How do RBCs carry CO2 to lungs?
CO2 can be carried via carbaminohaemoglobin then displaced by high pO2 in lungs. Also converted to HCO3 by carbonic anhydrase and expelled into plasma in exchange for Cl to maintain electrical neutrality. In lungs HCO3 re-enters RBC and converted to CO2 for excretion
What hormomes released from hypothalamus affect the release of hormones from the anterior pituitary?
CRH from hypothalamus - releases adrenocorticotrophic (ACTH) from anterior pituitary GnRH from hypothalamus- release LH and FSH from anterior pituitary TRH from hypothalamus - releases TSH from anterior pituitary GHRH from hypothalamus - releases GH GHIH/somatostatin from hypothalamus - inhibits release of GH PIF/dopamine from tuberoinfundibular dopamine neurons - inhibits prolactin (PRL) release
What do cerebral ventricles contain and what structure surrounds ventral horn of lateral ventricle?
CSF Basal ganglia
Describe the passage of CSF after its formation and what causes hydrocephalus?
CSF travels from lateral ventricles to 3rd ventricle via interventricular foramen then into 4th ventricle via cerebral aquaduct. Hydrocephalus caused by blockage of CSF drainage
How is muscle glycogen breakdown linked to contraction?
Ca binds to calmodulin sensory subunit of phorsphorylase kinase and promotes enzyme activity, therefore phosphorylating and activating glycogen phosphorylase
What are the processes that cause skeletal muscle contraction?
Ca binds to troponin --> conformational change that pulls tropomyosin away from myosin binding site --> myosin hydrolyses ATP --> myosin head binds actin and neck bends --> muscle contracts --> myosin releases actin when new ATP attaches --> muscle relaxes
What is the mechanism of muscle contraction causing glycogen breakdown?
Ca entry into cell --> causes muscle contraction --> decreases [ATP] and increases [ADP] and [AMP] -->increased AMP activates phosphorylase kinase
How does [Ca], NADH and ATP affect the PDC and how do Ca and ADP affect TCA enzymes?
Ca promotes dephosphorylated/activated state of PDC. Low NADH and ATP inhibit PDH kinase (phosphorylates/deactivates PDC). Ca and ADP also promote isocitrate and a-ketoglutarate dehydrogenase activity in TCA
What is anion gap and normal range?
Calculates difference between measured and non-measured cations/anions and indicative of metabolic acidosis. Normal - 8-12mmol/L. High AG - lactic acidosis, ketoacidosis, toxins and renal failure, normal AG - GI or renal HCO3 loss
How do hormones released from anterior pituitary act on target tissues and how are they controlled?
Can act directly (eg. prolactin stimulating milk formation in lactating breast) or indirectly (stimulating release of further hormones or cytokines (eg. ACTH acting on adrenal cortex to stimulate cortisol release)) Controlled by feedback inhibition from final hormone
What are chromosomal abberations and what diseases can they cause?
Can affect large portions of a chromosome and many genes. Deletion - portion of chromosome removed, inversion - part of chromosome detaches and attaches reversed (little effect if balanced), translocation - part of chromosome breaks off and attaches to another chromosome, duplication - part of chromosome breaks off and attaches to sister chromatid. Nondisjunction - chromosomes fail to separate properly.
What are the sources of free radicals, what can they be, what can they affect and what are antioxidants?
Can be ROS or RNS. Come from endogenous (mitochondria, peroxisomes) or exogenous (pollution, alcohol, smoke, heavy metals) sources. Can affect nucleic acids, lipids and proteins. Antioxidants neutralise free radicals by donating an electron
How can DCML function be assessed?
Can be assessed with proprioception (using Romberg's test), fine touch (recognising common objects), vibration sense, barognosis (determining approximate weight), graphesthesia (recognise writing on skin) and kinaesthesia (detect externally imposed passive movement)
What are the causes and consequences of protein misfolding?
Can be caused by inherited mutations or environmental stress, causing toxic gain or loss of function and neurodegenerative disease, metabolic disorders or cancer
What are the causes of avascular necrosis?
Can be caused by sickle cell anaemia, corticosteroid use and embolism/thrombosis
How is vitamin D provided, what is it used for and what can deficiency cause?
Can be made from sunlight then processed in liver or kidney. Used for Ca absorption and bone health. Deficiency can cause osteomalacia (reduced bone strength and increased bone fractures) or Ricket's (prior to fusion of epiphyseal growth plates and due to expansion of growth plates at knees)
What electrolyte imbalance can ecstasy use cause and how is it treated?
Can cause ecstasy-induced hyponatremia by dumping of Na+ and holding H2O, causing convulsions, coma and death. Treated by restoring balance of Na+ and H2O
What can pacemaker cells in smooth muscle do?
Can create spontaneous slow wave potentials by generating regular and repetitive oscillations in membrane potential
What structures can be damaged during surgery of carotid triangle and what symptom does this cause?
Can damage vagus or recurrent laryngeal nerves to cause alteration in voice
What are the functions of integral proteins?
Can diffuse laterally or be anchored, can change conformation and be internalised and recycled.
How can microbes enter body and how are we exposed?
Can enter through skin, respiratory system, oral/GI, urinary system, placenta and blood. Exposed by direct contact (cough, sneeze), airborne transmission, vectors or food-borne
How can monosaccharides be modified and what are sulphated sugars?
Can form deoxy sugar (removal of OH), replace OH group with PO4 (phosphorylated sugars), SO4 (sulphated sugars) or NH2 (amino sugars). Sulphated sugars from sulpho-transferases and important in ECM GAGs because attract water due to -ve charge
Describe monosaccharides
Can form enantiomers (D form most common where OH group on right of asymmetric C and can be digested). Can form cyclic structures where C5 OH reacts with aldehyde/ketone group
Describe self-sufficiency in growth signals
Can grow independent of external growth signals and can form autocrine loops
How can antibiotics inhibit bacteria and what are the types of antibacterials?
Can inhibit cell wall synthesis, RNA transcription/replication, protein synthesis, DNA replication. Bactericidal (kill bacteria) or bacteriostatic (inhibit growth) and broad or narrow spectrum
How can pituitary tumours affect weight?
Can press on hypothalamus so patients develop large appetite, morbid obesity and hypogonadism due to hypothalamus damage
What are muscarinic agonist examples?
Carbachol produces global effects. Bethanechol increases bladder and GI contraction. Pilocarpine causes miosis (used for glaucoma)
What does the oculomotor nerve carry and what does an oculomotor nerve palsy cause?
Carries motor fibres to superior/inferior/medial rectus, inferior oblique and levator palpabrae superioris (attaches to eyelid). Also carries parasympathetic fibres for contrictor pupillae and ciliary body (changes lens thickness). Palsy causes eye to rest in depressed and abducted position
What type of joint are IVDs and what are the layers of an IVD?
Cartilaginous joint made from thin layer of hyaline cartilage Outer annulus fibrosus (fibrocartilage layer) and inner nucleus pulposus (gelatinous central mass found further posterior)
Describe peritoneal dialysis
Cather inserted into abdomen and cleansing fluid inserted. Abdomen acts as a filter and remaining waste fluid drained away. Used for kidney failure
What are compliment proteins?
Cause cascade that produce pores in cell wall/membrane and cause lysis
How do antibodies work?
Cause neutralisation (can't bind to CD4), agglutination (hold cells together for phagocytosis), opsonisation (marks for destruction), antibody-dependent cell killing (by NK cells) and activation of complement
What causes cardiac pain and, why is cardiac pain referred and where is it felt?
Caused by cardiac muscle damage or ischaemia that stimulates visceral sensory nerve endings. Visceral afferent fibres ascend to CNS through cardiac branch of sympathetic trunk and travel parallel with skin pain fibres. Skin supplied by T1-T5 is l side of chest, neck, face and arm. Inferior wall infarcts have referred pain in epigastrium (T7-T9)
What causes superior laryngeal nerve paralysis and what does this cause?
Caused by compression (goitre) or during thyroidectomy and causes superior laryngeal mucosa anesthesia (loss of cough reflex) and monotonous voice (due to cricothyroid paralysis so unable to change length/tension)
What is Marfan syndrome?
Caused by fibrillin misfolding so transforming growth factor not bound with ECM so accumulates in lungs and hearts so alters ECM. Symptoms - arachnodactyly, tall, long limbs, loose joints, floppy cardiac valves, aortic aneurysms
What are the causes of lower GI IBS symptoms and how are they treated?
Caused by gastroenteritis, leaky gut epithelium, visceral pain hypersensitivity, abnormal ENS neuron activity. Treated using dietary control and treating specific symptoms
What causes raised ICP, what are the symptoms and what is a fatal consequence of raised ICP?
Caused by haemorrhage, tumour, berry aneurysm or brain swelling Symptoms - nausea, vomiting, headache, bouts of unconsciousness Raised ICP can cause brain tissue herniation (subfalcine, uncal or tonsillar)
What causes oedema and what factors can cause these?
Caused by increased filtration or decreased reabsorption that are caused by increased HPc, decreased OPc, lymphatic obstruction or increased capillary permeability
What movements typically cause a sprained ankle and what ligaments are damaged in a sprained ankle?
Caused by inversion + plantarflexion Damages anterior talofibular and calcaneofibular
What are the causes of gait problems?
Caused by mechanical (OA, muscle strains or blisters) or neurological (perception deficits or nerve damage) issues
What is baker's cyst, what is it associated with and how can it restrict normal movement?
Caused by normal bursa or herniation of joint capsule on posterior surface. Normally associated with meniscal tear or degenerative arthritis and restricts normal movement due to posterior location
What causes generalised malabsorption, what causes malabsorption in mucosal phase and what causes coeliac disease?
Caused by small intestine disease or pancreatic disease. Malabsorption in mucosal phase from decreased absorptive SA (eg. coeliac disease). Coeliac disease caused by autommune response to gliadin peptide in gluten that destroys villi of intestine
What are the causes of facial nerve palsy and what does each cause?
Caused either by direct facial nerve compression (Bell's palsy) or stroke. Bell's palsy causes complete loss of motor supply to ipsilateral face and stroke (causes UMN lesion) causes paralysis of lower half of contralateral face
What are the causes, symptoms and disorders caused by bone marrow failure?
Causes - B12/folate deficiency, leukaemia and other cancers, chemotherapy and radiation, toxins. Symptoms - fatigue, bleeding, infections and death. Disorders - thrombocytopenia, leucopenia and anaemia
What does calcaneal tendon rupture cause?
Causes loss of shape to back of ankle and inability to plantarflex
What is the effect of high ICP on pupil size?
Causes mydriasis due to compression of oculomotor nerve
What happens to muscle spindles when a muscle is stretched and with tendon tap?
Causes stretching of muscle spindles so increase firing rate. WIth tendon tap, small stretch of muscle enough to increase spindle firing to activate reflex
How does SNS react to haemorrhage?
Causes venoconstriction to maintain venous return. If severe, vasoconstriction of non-essential organs to maintain BP and vital organ perfusion. Renin release maintains BP by angiotensin II formation. ADH release reduces fluid loss
How do patients with cerebellum, basal ganglia, association motor cortex, descending pathway, NMJ or LMN injury/damage present?
Cerebellum - ataxia and hypotonia Basal ganglia - hyper/hypokinesia Association motor cortex - apraxia Descending pathway - spasticity and hypertonia NMJ - neuromuscular disorders LMN - muscle atrophy
What are channel and transport proteins?
Channel - continous pores that can be regulated or selective and work down gradient with high bulk flow. Transporters - specific binding sites exposed on membrane so low capacity
What are the types of membrane proteins?
Channel proteins (open and close to allow movement of ions, CFTR), transport proteins (can facilitate diffusion or active transport, drug efflux pumps), receptors (for transmission of signals and endocytosis, TRK), integrins/adhesins/connexins (bind cell to ECM or other cells)
What are the types of synapses?
Chemical (impulses passed indirectly using NTs) and electrical (impulses passed directly using gap junctions)
What are chemical and physiologic antagonists?
Chemical - bind directly to agonist and prevent binding, physiologic - have opposite action via different pathway
How do cholera toxin and staphylococcal enterotoxin affect the body?
Cholera toxin stimulates gut wall proteins so massive electrolyte and water efflux. Staphylococcal enterotoxin acts as superantigen to cause huge cytokine release
What can over-uptake of cholesterol cause and how can this be prevented?
Cholesterol deposition in arterial wall and atherosclerosis/CHD. Can eat less cholesterol, eat phytosterols or use statins as a competitive inhibitor of HMG-CoA reductase that synthesises cholesterol
What are the sources of cholesterol, what is it used for and what is a medication used to decrease blood cholesterol?
Cholesterol is exogenous (diet) or endogenous (from liver). Used for cell membranes, steroid/bilesalt synthesis and skin. Statins used as they inhibit HMG CoA reductase
What is cholestyramine, how does it work and what are potential side effects?
Cholestyramine is a bile acid binding resin that binds to bile acids in the gut and prevents enterohepatic circulation, decreasing the amount of bile acids. More bile acid has to be made from cholesterol so decreases [LDL]. Side effects - nausea, vomiting, abdo bloating, flatulence and alteration of bowel habits. Not systemically absorbed so good safety but fat soluble vitamin supplements may be needed
What does stimulation of postganglionic cholinergic and noncholinergic fibres cause in the respiratory tract?
Cholinergic stimulation of M3 GPCRs causes smooth muscle contraction and increased mucus secretion via goblet cells. Noncholinergic stimulation causes bronchial muscle relaxation mediated by NO and vasoactive intestinal peptide (VIP)
Where is CSF formed and what glial cells are involved in CSF formation?
Choroid plexus (meshwork of capillaries surrounded by ependymal cells), mostly in lateral ventricles
What is chromatin and what are the different types?
Chromatin is DNA complexed with proteins. Euchromatin is loosely packed and is for transcription (light on EM), heterochromatin is dense and for gene regulation (dark on EM)
What is gastroparesis, what are symptoms, what causes diabetic gastroparesis, what can it lead to, how is it diagnosed and how is it treated?
Chronic condition of delayed gastric empyting. Symptoms - bloating, rapid feeling of fullness, nausea, vomiting, reflux and pain. Diabetic gastroparesis due to neuropathy of vagal endings. Can lead to malnutrition, formation of bezoars (hardened mass of undigested food) and changes to blood sugar. Diagnosed using gastric emptying study (using C13 labelled meal). Treated using domperidone or erythromycin (stimulate stomach muscle contraction), anti-emetics for nausea and dietary changes (smaller, more frequent meals)
Describe chylomicrons, VLDLs, IDLs, LDLs and HDL and what is the function of apoE?
Chylomicrons - low density, main transport is TAG, has apoB48 (also A, C and E) VLDLs - low density, main transport is TAG, has apoB100 (also A, C and E) IDL - intermediate density, main transport is TAG and cholesterol, has apoB100 (also E) LDL - low density, main transport is cholesterol, has apoB100 HDL - high density, main transport is apoprotein, has apoA-I, apoA-II (also C and E) ApoE has a role in lipoprotein removal from blood
Describe the post-absorptive phase of lipid digestion
Chylomicrons secreted by exocytosis into lymphatic capillaries
What are C, D and E in CXR interpretation?
Circulation - aortic knuckle, heart size (cardio-thoracic ratio <50%) and borders of heart. Diaphragm - right hemidiaphragm higher, costophrenic/cardiophrenic angles and stomach on right. Everything else - ETT, NGT, CVC, valves, pacemaker, thoracotomy wires, soft tissue, bones
What molecule from TCA can be used to make fatty acids and how and what can be used for AA synthesis?
Citrate used to make fatty acids. Transported to cytosol then converted to acetyl CoA which can be used for fat and cholesterol synthesis. Oxaloacetate and a-ketoglutarate can be used for AA synthesis
What does the clavicle do to the shoulder, how does the shoulder position change after a clavicle fracture, what are the muscles that connect to the clavicle and what do they do?
Clavicle pushes shoulder joint away from thorax so the shoulder drops if clavicle is fractured. Sternocleidomastoid (connects to medial clavicle and pulls it superiorly) and pectoralis major (attaches to anterior humerus and sternum) connect to clavicle
What is clearance, how is it calculated and when does it equal GFR, 0 and RPF?
Clearance is the volume of blood completely cleared of a substance per minute (L/min). Clearance = [urine]/[plasma] x urine flow. Equal to GFR when 100% filtered by glomerulus and 0% is reabsorbed. Equal to 0 if all filtered material is reabsorbed and equal to RPF if all material is filtered and secreted into lumen and not reabsorbed
How can cancer cells migrate?
Cleavage of cell-adhesion molecules causes migration into surrounding tissue/vasculature. Loss of integrins allows cancer to break through BM
What are enzyme cofactors, prosthetic groups, apoenzymes, holoenzymes and co-enzymes?
Co-factors are non-protein components required for activity. Prosthetic groups are non-dissociable cofactors. Apoenzymes are enzymes lacking cofactor so inactive. Holoenzymes are enzymes with cofactor so active. Co-enzymes are dissociable non-proteins that transfer molecules between enzymes
What are the types of bacteria and streptococci/staphylococci?
Cocci (spherical), bacili (rod) and spirochaetes (curved/spiral). Streptococci are chains, staphylococci are clusters
What does DNA include?
Coding portions (exons), non-coding regions and evolutionarily conserved portions (promotors, enhancers, transposons (parts of DNA that can move position) and microsatellites)
What are coding sequences, non-coding sequences, control elements, pseudogenes and repetitive sequences?
Coding sequences - DNA that codes for proteins, non-coding sequences - DNA that doesn't code for proteins (intergenic regions, introns and control elements), control elements - promoter and enhancer regions, pseudogenes - non-functional copies of a gene from gene duplication, repetitive sequences - tandem repeats of closely related DNA
What are the main prevertebral ganglia and the names of the preganglionic axons to coeliac and mesenteric plexi?
Coeliac ganglion and plexus, inferior mesenteric ganglion and plexus and hypogastric plexus. Greater and lesser splanchnic nerves to coeliac and mesenteric plexi
What do the coeliac plexus, inferior mesenteric and hypogastric plexi innervate?
Coeliac plexus - liver, stomach and small intestine, inferior mesenteric - rest of gut, hypogastric - bladder and reproductive organs
Where do the coeliac trunk, SMA and IMA branch from the abdominal aorta?
Coeliac trunk branches at T12, SMA branches at L1 and IMA branches at L3
What are the different roles of micronutrients and give an example of each?
Cofactors - non-protein compounds needed for biological activity (iron/zinc) Coenzymes - help enzymes to catalyse reactions (TPP) Antioxidant - inhibits oxidation of other molecules (vitamin C) Genetic control - control of gene expression (vitamin A and D) Structure - phospholipids form complexes with Mg and Ca to form various cellular membranes
What are cohesins and the kinetochore?
Cohesins hold together sister chromaids so cohesinopathies can cause extra/missing chromosomes. Kinetochore made from inner (binds to centromere using specialised H3) and outer subunit (interacts with spindle)
What features are found at myotendinous junction and what is a microscopic indicator of muscle repair?
Collagen fibres of tendons that are continuous with connective tissue of muscle Central nuclei indicative of repair
What are tonsils, what are the tonsils found in Waldeyer's ring and what are the arches in the oral cavity?
Collections of lymphoid tissue. Palatine, lingual (posterior tongue), tubal (lateral nasopharynx) and pharyngeal tonsils (superior nasal cavity). Palatoglossal (anterior) and palatopharyngeal (posterior) arches
Where do coronary arteries come from, how do they fill and which coronary artery supplies nodes?
Come from ascending aorta and ostia are in anterior leaflets of aortic valve and fill during diastole when valves close. RCA supplies nodes.
Where do blood cancers come from and what are examples?
Come from haematopoeitic and lymphoid tissues. Leukemia comes from bone marrow (lymphoid, myeloid, acute or chronic). Lymphomas from lymphoproliferative system (hodgkin's and non-hodgkin's) and multiple myelomas are neoplastic proliferations of B cells in bone marrow so plasma cells produce paraprotein (abnormal antibody) to cause paraneoplastic syndromes
What are the sources of sarcomas?
Come from mesenchymal (connective) tissue. Can be bone, soft tissue (muscle, cartilage, fat, nerves, fibrous tissue, blood and lymph vessels)
What are sources of genetic variation and what do they determine?
Come from mutations in DNA, shuffling of parental DNA during sexual reproduction and determines development and maintenance, senses and disease susceptibility
What is the blood supply to the abdomen?
Comes from superior epigastric artery (division of internal thoracic artery), inferior epigastric artery (runs posterior to rectus abdominis and is branch of external iliac artery) and lateral blood supply from lower intercostal and lumbar arteries
What is the sympathetic innervation to the head, how do fibres travel into head and what does disruption cause?
Comes from thoracic region of spinal cord and fibres travel into head with ICA. Disruption to ascending sympathetic nerves causes Horner's syndrome (miosis, anhydrosis and partial ptosis)
What provides the posterior circulation of brainstem, what do these arteries give off and fuse to form and what is the function of the posterior communicating arteries?
Comes from vertebral arteries (fuse at base of pons to form basilar artery). Give off PICA/AICAs and anterior/posterior spinal arteries and also SCA and PCA at junction of pons and midbrain. PCoA connects anterior and posterior circulations
What are the common and specific symptoms of unilateral medial brainstem lesions?
Common - CST (contralateral spastic hemiparesis) and medial lemniscus (contralateral loss of discriminatory touch) damage Midbrain - common symptoms + ophthalmoplegia Pons - common symptoms + medial eye deviation Medulla - common symptoms + ipsilateral weakness and wasting of tongue muscles
What are the common and specific symptoms of unilateral lateral brainstem lesions?
Common - contralateral loss of pain/thermal sensation (STT damage), ipsilateral loss of facial skin sensation, Horner's syndrome, nystagmus, vertigo, nausea and vomiting, ipsilateral limb ataxia Midbrain - contralateral hemi-anaesthesia Pons - deafness or tinnitus, loss of taste, complete ipsilateral facial muscle paralysis Medulla - dysphagia, hoarseness, ipsilateral loss of gag reflex, loss of taste
What are the main arteries of the lower limb?
Common iliac arteries --> external iliac --> femoral --> popliteal --> posterior/anterior tibial --> arcurate --> digital branches
Where do aneurysms commonly occur, how do they present and how are they treated?
Commonly occur in the cerebral arteries as they are highly twisted. Present incidentally on MRI/CT, rupture and cause subarachnoid haemorrhage or cause symptoms when pressing on neural structures. Treated by clipping or coiling
What are the functions of the oral cavity and what are the oral vestibule and oral cavity proper?
Communication, ingestion, digestion and respiration. Oral vestibule between lips and gums/teeth and oral cavity proper is everything behind teeth
How does pulmonary circuit compensate for lower pulmonary pressure? What is pulmonary arterial hypertension and what can it cause?
Compensates by decreasing pulmonary vascular resistance. Pulmonary arterial hypertension increases pulmonary arterial resistance so increases right heart afterload to cause right heart failure
What is impedance matching?
Compensates for impedance mismatch between air and cochlea fluid by difference in area between ear drum and oval window
What causes complete and incomplete spinal cord injuries and what do each cause?
Complete spinal cord injury caused by full compression/severe so complete loss of sensory/motor info below level of lesion Incomplete injury caused by partial compression/injury but ability to send signal below site of injury not completely removed
What are the complexes found in the ETC, which complexes pump H+ and what can inhibit complex IV
Complex I (electrons from NADH to UQ), complex II (electrons from FADH to UQ), complex III (electrons from UQ to cytochrome C) and complex IV (electrons from cytochrome C to O2). Complexes I, III and IV pump H+. Complex IV can be inhibited by cyanide and CO
What is the function of the ECM?
Complex network of macromolecules that reuglates proliferation, differenatiation, migration, cell-cell interaction, growth factor regulation, cell polarity and intracellular processes
What happens to compliance in the elderly?
Compliance decreases as elastin replaced with collagen. This increases afterload which increases period of isovolumetric contraction so shorter duration of ejection and larger ESV and therefore smaller SV and CO
What is lung compliance, what happens at high expanging pressure, how is lung volume different during inspiration/expiration and why is there always air in the lungs even without expanding pressure?
Compliance is the change in volume with a given change in pressure. At high expanding pressure, compliance decreases as the lung is stiffer. During inspiration a greater pressure is required to create the same lung volume compared to expiration. Some air always in lungs due to airway closure that traps gas in alveoli
What is the confluence of sinuses?
Confluence of sinuses found at posterior-inferior brain where superior sagittal, transverse and straight sinuses all meet
What is different about conjugated bile acids and what is the role of commensal bacteria in the gut?
Conjugated bile acids are more efficient because at intestinal pH they are more ionised. Commensal bacteria deconjugate bile acids so make them less efficient so are key regulators of digestion
What are connective tissue cells and what are their functions?
Connective tissue cells make ECM. Adipocytes, osteocytes, haemopoietic cells, chondrocytes (cartilate), fibroblasts (collagen)
What does the medial ligament connect, how many parts does it have and what does it do/prevent?
Connects medial malleolus to calcaneus and navicular Has 4 adjacent/continuous parts so is very strong and stabilises eversion and prevents subluxation
What is the Eustachian tube, what does it do, what epithelium is it lined with and how does it change with altitude?
Connects middle ear to nasopharynx and equalises pressure and drains middle ear using ciliated pseudostratified columnar epithelium. When decreasing altitude, air pressure causes tube to collapse, causing blocked ear feeling
What is the difference between conserved and consevative?
Conserved - where AA is common in genomes or organisms. Conservative - different AA but similar properties
What are the main methods of transport in/out of cells?
Constitutive excretion (exocytosis) - cells release molecules, endocytosis - cells absorb molecules, lyososomes - digest absorbed molecules by endocytosis. Secretory vesicles regulated by signals
What are the types of cell-cell communication?
Contact, paracrine (local mediators released from signalling cell), endocrine (released into bloodstream) and synaptic
What are structural/functional features of bacteria?
Contain RNA and DNA in free circular chromosome. Also contain plasmid and divide by binary fission. Contian 70s ribosomes, no membrane-based organelles but have flagella and pili/fimbriae, capsule (made from glycocalyx) and some produce spores
What do terminal boutons contain and what is a characteristic of muscle membrane under each bouton?
Contain lots of mitochondria and synaptic vesicles containing ACH Membrane is greatly folded to increase SA
Why are CD8 cells not affected by toxic proteins?
Contain serine protease inhibitors so effector molecules have no effect
What is the thoracic cavity and what is found there?
Contains 2 pleural cavities (one for each lung) and mediastinum (contains heart, trachea, oesophagus, aorta, great vessels, vagus and phrenic nerves). Fibrous pericardium surrounds heart and can't expand
What is the function of the medial hypothalamus in control of eating and what can lesions cause?
Contains arcuate and periventricular nuclei so contains satiety centre Lesions produce obesity
What is the cranial cavity and what are the layers of membrane?
Contains brain and surrounded by meninges (dura mater connected to skull, arachnoid mater with CSF beneath, pia mater that follows brain)
What is the function of the lateral hypothalamus in control of eating and what can lesions cause?
Contains orexigenic (hunger) centre Lesions produce anorexia
What is found in the cardiac plexus and what do the SNS/PNS do to the heart?
Contains parasympathetic (from vagus), sympathetic (from sympathetic trunk) and visceral sensory afferents. SNS increases HR and contractility by stimulation of medulla cardioacceleratory centre. PNS slows HR from cardioinhibitory centre
What joints are found in the vertebral column, what curves does it have, what is the function of vertebrae and where do spinal nerve roots emerge?
Contains planar synovial facet joints and IVDs. Has 4 curves (cervical, thoracic, lumbar and sacral). Vertebrae protect spinal cord and spinal nerve roots emerge between intervertebral foramen (can be trapped by hyperextension)
What is the brachial artery, where does it run and end, what is its major branch (where does this run and what does it supply) and where is the brachial pulse found?
Continuation of axillary artery which runs superficial on anterior side and ends 1cm below elbow. Major branch is profunda brachii (deep) which runs down posterior side and supplies triceps. Brachial pulse found medial to distal tendon of biceps brachii
What is the femoral artery, where does it pass and where can you find the femoral pulse?
Continuation of external iliac artery as it passes under inguinal ligament. Passes down anteromedial thigh and pulse found below inguinal ligament and mid-inguinal joint and halfway between pubic symphysis and anterior superior iliac spine
What is the axillary artery, where does it start and end, where does it run through and what do its branches supply?
Continuation of subclavian artery. Starts at lateral border of 1st rib, runs through axilla and ends at lateral border of teres major. Branches supply chest wall and shoulder girdle and forms humeral circumflex
What are the different types of capillaries and where is each type found?
Continuous (skin, muscle, lung and CNS), fenestrated (glomeruli, pancreas, intestines and exocrine glands) and discontinuous (liver, bone marrow and spleen)
What is the structure of continuous capillaries, what transport do they allow and what types of vesicles are found in different sites?
Continuous basement membrane with sealed endothelium that allows diffusion of small molecules. Can have numerous transport vesicles (gonads, skin, muscle, lungs) or few vesicles (in BBB)
What are the consequences of ACA stroke?
Contralateral sensorimotor loss below waist, urinary incontinence, personality defects and split-brain syndrome
What is the function of the cerebellum and how does it do this?
Control of complex multi-joint movements. Controls by receiving direct input from muscles and comparing with intended signal for movement
What is the function of precapillary sphincters and what are arteriovenous malformations?
Control the amount of blood passing through a capillary bed by shunting blood through arteriovenous anastomosis. AVMs consist of tangles of abnormal blood vessels where arteries directly connect to venous drainage without capillary bed. AVMs are a risk to health due to bleeding/haemorrhage due to large pressure difference
What controls enzyme flux and what are the features of rate-controlling enzymes and give an example?
Controlled by energetics, push/pull, regulation of enzymes and compartments. Rate-controlling enzymes normally at start of pathway, are unidirectional, have relatively low activity and multiple subunits. PFKinase 1
What structure controls accommodation reflex and what does damage to this area cause?
Controlled by frontal eye fields (FEFs) and only occurs in conscious people. Damage to this area causes inability to focus on near objects to cause diplopia and inability to directly gaze from one object to another
How is MHb converted to Hb and what is a high MHb level called?
Converted using NADHPH-dependent methaemoglobin reductase. High MHb called methaemoglobinaemia
Describe hinge joints and where are they found?
Convex surface of one bone fits into concave surface of another to allow flexion/extension. Found in elbow and knee
What is the Cori cycle and what does it allow?
Cori cycle allows for anaerobic respiration in muscles by converting lactate to glucose in the liver using energy from fats. In muscle, conversion of pyruvate --> acetyl CoA must be inhibited by increasing acetyl CoA (from FA oxidation) that inhibits pyruvate dehydrogenase complex
What are the structures in the centre of the brain?
Corpus callosum (connects 2 hemispheres), ventricle that holds CSF, thalamus for relay
What are the different epigenetic mechanisms?
DNA methylation, histone modification, nucleosome modification, change of chromatin architecture and micro RNAs
How can nucleosomes be modified?
DNA packing prevents gene transcription. Nucleosome sliding, unwrapping, eviction, dimer replacement or ejection all affect DNA availability
What is BRCA and what do BRCA1/BRCA2 do?
DNA repair proteins that repair dsDNA crosslinks at G2/M checkpoint. BRCA1 triggers p21 and repairs DNA so deficient cells have genomic instability. BRCA2 facilitates homologous recombination (HR) so deficient cells defective in repairing double strand breaks
Where do DNA and RNA viruses replicate?
DNA viruses replicate in nucleus, RNA viruses replicate in cytoplasm
How can damage spread in axons?
Damage can spread through anterograde (towards axon terminal, Wallerian degeneration) or retrograde degeneration (towards cell body, axonal die-back), trans-neuronal degeneration or to cell body
What does O2 carriage depend on and how is this controlled?
Depends on haematocrit (normally 45%) which is controlled by EPO. Renal hypoxia triggers more EPO production so more RBC production in bone marrow
What effect do COPD and age have on compliance and how does this cause V/Q mismatch?
Decrease compliance at base so further reduces V/Q at bases and decreases O2 uptake in zone where blood flow is high
What is sinus arrythmia, how is it caused and what drug stops it?
Decrease in HR on expiration, caused by increased parasympathetic outflow on expiration and decrease on inspiration. Stopped by atropine as it blocks parasympathetic effect
What is respiratory acidosis and what are the causes?
Decreased pH from CO2 retention. Caused by hypoventilation (inadequate mechanical ventilation, COPD, respiratory centre depression), excess CO2 production, sepsis, burns
What is metabolic acidosis and what are the causes?
Decreased pH from excess HCO3 loss (chronic diarrhoea) or acid production (DKA, lactic acidosis or toxins like aspirin)
What is the transversus abdominis muscle, what direction do its fibres run, where does it end and what is it used for?
Deep layer of lateral abdominal wall. Fibres run in transverse direction. Becomes aponeurotic at midclavicular line and used for trunk rotation and changes in abdominal pressure (increases pressure on contraction)
What causes CFTR and what are CF treatments?
Deletion of phenylalanine that causes inefficient folding. CFTR phosphorylated by PKA (cAMP dependent) and is ATP gated. Lumacaftor improves folding and ivacaftor increases opening size
How do T cells help B cells?
Dendritic cell MHC-II presents antigen to TCR in lymph nodes. BCR also binds antigen, internalises, degrades then presents on MHC-II which binds to TCR. T cell produces cytokines that stimulate antibody production
What do dense core and small clear core vesicles contain?
Dense core - larger NTs (neuropeptides). Small clear core - smaller NTs (AAs, amines)
What does work of the heart depend on (in relation to blood) and what is this affected by?
Depends on blood viscosity which depends on haematocrit (% of RBCs, normal 45%).
What does the rate of diffusion depend on?
Depends on diffusion distance, difference in concentration, SA and diffusion coefficient
Describe the stages of Ca signalling during cardiac muscle conctraction and what is the role of ATP in muscle contraction?
Depolarisation from Na influx opens LTCC (L-type Ca channels) so increases intracellular Ca which triggers further release from SR by ryanodine receptor (RyR). Ca associates with troponin C in sarcomere to initiate contraction. Events terminated by release of Ca from sarcomere and reuptake into SR. ATP hydrolysis provides energy to drive filament sliding
What are end plate potentials and what is a characteristic of them?
Depolarisation of skeletal muscle fibres caused by NTs binding to postsynaptic membrane in NMJ. Have fast rise time and slow fade
What are the key ion channels involved in the cardiac muscle action potential?
Depolarising (Na and Ca, influx) and repolarising channels (K, efflux)
What are the types of NMJ blockers, give examples of curare derivatives, what is their antidote and how is antagonism overcome?
Depolarising and non-depolarising Atracurium, pancuronium, rocuronium etc. Antidote is ACHE inhibitor (eg. neostigmine, physostigmine) which increases [ACH] to overcome antagonism
What are base modifications?
Depurination (loss of purine base), deamination (C deaminated to U), tautomeric shift (base substitution)
What are sources of spontaneous DNA damage?
Depurination, depyrimidation (both cause base pair deletion), deamination and oxidation
How is lipid envelope derived?
Derived from host cell membrane. Contains glycosylated surface projections
What are dermatomes and 2 example?
Dermatomes are areas of skin innvervated by same nerve. Nipple - T4, umbilicus - T10
What is Anton-Babinski syndrome?
Despite blindness due to damage to visual cortical pathway (eg. stroke) some patients insist they can still see and make up their visual surroundings
What determines ventricular contractile force and what is preload?
Determined by end diastolic volume. Preload is degree of stretch of ventricles during diastole and proportional to EDV
What causes abnormal spinal curvature and what is kyphosis?
Developmental anomalies or pathological conditions (missing half vertebrae or osteoporosis) Kyphosis/humpback is increased thoracic curvature caused by erosion/fracture of anterior part of vertebrae
What are the diagnosis methods for H pylori?
Diagnosed using urea breath test where C14 urea given to patient and C(14)O2 production measured. Also CLO test where biopsy placed in media with urea and pH indicator (urea conversion --> NH3 raises pH). Can also use blood antibody or stool antigen tests
What are the indications for colonoscopy?
Diagnosis (rectal bleeding, altered bowel habit, abdo pain), surveillance and therapy (polypectomy, dilatation and stent insertion)
What is the therapeutic index?
Difference between effective dose and toxic dose
What produces intraocular pressure, what can cause this to rise and what can this result in?
Difference between formation and drainage of aqueous humour. Can rise due to reduced drainage and can result in retinal damage and glaucoma
What are determinants of tumour classification?
Differentiation state (epithelial, non-epithelial or mixed), embryonic origin (endoderm, mesoderm or ectoderm) and how cell behaves (malignant/benign)
What factors determine the volume of gas per unit time that diffuses across a membrane?
Diffusion distance, partial pressure difference, surface area of membrane and diffusion coefficient
Describe the luminal phase of lipid digestion
Digested by lingual and gastric lipases. Bile salts and pancreatic lipase digest triglycerides into free fatty acids
What does the parasympathetic system do?
Digestion, diuresis and defecation. Increases salivary gland secretion, GI motility and secretion, bladder contraction, sphincter relaxation, decrease HR and contractility, bronchoconstriction, miosis, lacrimation and erection
What signals are converted at a synapse and what is summation?
Digital signals (action potential) converted to analogue signals (NTs). Summation is cumulative effect of excitatory and inhibitory signals
What is an enzyme-linked receptor?
Dimer signal molecule pulls two proteins together and activates them. In receptor protein kinase, subunits phosphorylated and activate downstream signalling
How do toxins released in diphtheria, tetanus and botulism affect the body?
Diphtheria - protein synthesis inhibited in cardiac muscle due to EF-Tu inhibition so aminoacyl-tRNA transfer inhbited. Tetanus - GABA release inhibited so irreversible muscle contraction. Botulism - prevents ACH release so flaccid paralysis
What are the types of DNA damage?
Direct - radiation from alpha, beta or x-rays create ions that break sugar-phosphate backbone and cause kink in DNA and pyrimidine dimer formation. Indirect DNA damage - production of oxygen radicals with free electrons that break bases or backbone
What does the dorsal column medial lemniscus (DCML) transmit and what is the pathway that its neurons take?
Discriminative touch, vibration and propriception from periphery to brain 1y neuron from periphery enters dorsal horn and travels directly into dorsal columns (split into fasciculus cuneatus for upper limb (lateral) or fasciculus gracilis (medial) for lower limb). 1y neuron synapses with 2y neuron in medulla which decussates and travels in brainstem to thalamus. 2y neuron synapses with 3y neuron in thalamus which travels to 1y somatosensory cortex
What happens after a peripheral nerve is cut?
Distal end degenerates as it isn't connected to cell body. Proximal end forms growth cone that grows back down inside sheaths guided by chemical factors on Schwann cell surface. Behind growth cone, Schwann cells proliferate and wrap myelin around fibre
What structure divides superior/inferior mediastinum and what plane does this form?
Divided by transthoracic plane (T4/T5) at manubriosternal joint
How is the walking cycle divided?
Divided into strides (activities between successive heel strikes on the same side) which are subdivided into stance and swing phases
Where does the posterior tibial divide, what does it form and what do these form?
Divides at ankle to form lateral (forms lateral end of plantar arch) and medial plantar arteries
What does the central sulcus divide, what is found either side of the central sulcus and what areas do these contain?
Divides frontal and parietal lobes and precentral (contains 1y motor cortex) and postcentral (contains 1y somatosensory cortex) gyri found either side of it
What does catalase test do?
Divides into streptococci (catalase -ve) and staphylococci (catalase +ve)
What are domains and the types of protein?
Domains - discrete portions of a 3D structure. Fibrous - dominated by one 2y structure or globular - mix of 2y structures
How is schizophrenia treated and what are side-effects of treatment?
Dopamine receptor antagonists (eg. antipsychotics/neuroleptics) but have low specificity so block other receptors Side effects - extrapyramidal effects (eg. parkinsonism), anticholinergic effects, rise in prolactin to cause weight gain, postural hypotension
What are the intrinsic muscles of the hand (apart from thenar/hypothenar) and what is their function and innervation?
Dorsal interossei (ulnar nerve) - abduct Palmar interossei (ulnar nerve) - adduct Lumbricals (medial fingers ulnar nerve and lateral fingers median nerve) - flex MCP and extend IP joints
What is the dorso-ventral organisation of the spinal cord?
Dorsal part (tectum) - CN nuclei and sensory reflex centres Middle part (tegmentum) - ascending pathways and reticular formation Ventral part - descending motor pathways
What roots carry sensory and motor information, what is the dorsal root ganglion and what is a mixed spinal nerve?
Dorsal root carries sensory info and ventral root carries motor info. Dorsal root ganglion in a collection of sensory neuron cell bodies. Mixed spinal nerve contains a group of sensory and motor nerves
How is the structure of the brainstem different to spinal cord?
Dorsal tracts move laterally and ventrally and motor nuclei move medially
What is high stepping gait?
Dorsiflexor paralysis (common peroneal nerve injury) causes foot drop so knee bend exaggerated to lift foot higher. Entire foot slaps on ground rather than heel strike
What muscles are used during early stance phase?
Dorsiflexors active at heel strike. Gluteus maximus and hamstrings extend hip and quads extend knee early in stance. Hip abductors active when going from single to double support
What is the function of the anterior compartment of the leg, what are the muscles and what is the innervation?
Dorsiflexors and toe extensors (deep peroneal nerve) Muscles - tibialis anterior, extensor digitorum longus and extensor hallucis longus
What drives asthma and COPD and what do they cause?
Driven by inflammation. Cause mucus hypersecretion, bronchoconstriction and emphysema in COPD
How can prodrugs be used in hypoxic cancer tissue?
Drug delivered and is activated by body's enzymes. In hypoxic conditions, Co3+ complex on EGFR inhibitor reduced to Co2+ so can interact with H2O and be released, leaving EGFR inhibitor free to bind to EGFR and prevent cell signalling and tumour growth
What are side effects of ACE inhibitors, how do these occur and in what populations are(n't) ACEi 1st line?
Dry cough and angioedema that occur due to increased bradykinin levels (vasodilator) by inhibiting degradation. ACEi not 1st line in afro-carribeans and over 55s due to increased risk of side effects
What is the structure of muscle spindles, what do they respond to (and how) and what fibres do they contain?
Encapsulated stretch receptor inside CT sheath that is sensitive to muscle stretch/length. Muscle stretch also stretches muscles spindle which activates muscle spindle sensory afferents (Ia afferents). Contains intrafusal fibres
What does the Circle of Willis encircle and what are the major branches/arteries?
Encircles optic chiasm and pituitary gland to give collateral circulation to cortex. ICA gives off PCoA before splitting into anterior cerebral and middle cerebral, then anastomoses with posterior cerebral arteries from basilar arteries. Anterior cerebral arteries form top of circle and anastomose to form ACoA
What encloses each glomerulus and what is the first step of urine formation?
Enclosed by Bowman's capsule. First step is filtration of plasma from golmerular capillaries into Bowman's space
What encloses rectus abdominis muscle?
Enclosed by aponeurotic sheath from aponeuroses of external and internal obliques and transversus abdominis
What is XPA gene and how can it contribute to cancer?
Encodes nucleotide excision repair proteins. XPA mutation causes xeroderma pigmentosum so pyrimidine dimers can't be removed so high risk of sunlight-induced melanoma
How do peripheral branches of sensory nerve fibres end in skin and what are the types of sensory receptors?
End as sensory receptors Can either be free nerve endings (eg. pain, temperature) or encapsulated endings (eg. vibration and detail)
What are the main cell checkpoints?
End of G1 (controlled by CDKI p16 which inhibits CDK4), end of G2 (activating phosphatase removes inhibitory phosphate on cyclin B/CDK1 complex) and metaphase (checks microtubule tension)
What is the function of the anterior pituitary and what surrounds the pituitary gland?
Endocrine gland Surrounded by cavernous sinus
What is endogenous and exogenous damage?
Endogenous - indirect carcinogens that need to be metabolised (alcohol, polycyclic aromatic hydrocarbons). Exogenous - direct carcinogens (UV, XR, oxygen species)
What is paediatric treatment for CD?
Enteral nutrition for 4 weeks that replaces normal diet and promotes epithelial healing
Where does fluid pass after Bowman's capsule, what are the processes ocurring in the PCT and how can excretion be calculated?
Enters PCT. Reabsorption (into interstitium) and secretion (into lumen) occur. Excretion = filtration - reabsorption + secretion
Which arteriole does blood enter and leave through and which forms peritubular capillaries and vasa recta? Which has a higher pressure, why is this significant and what is filtration fraction?
Enters through afferent and leaves through efferent (also forms peritubular capillaries and vasa recta). Afferent pressure is higher to create a hydrostatic pressure that forces fluid into glomerulus. Filtration fraction is percentage of plasma that is filtered (normally 20%)
What are the stages of microbial infection?
Entry --> local/general spread --> evasion of defence --> multiply and reprodue --> damage host --> exit from body --> host response
Describe the typical infectious disease pattern
Entry of pathogen --> colonisation --> incubation period --> prodromal stage --> period of illness/invasion --> convalescence
What influences disease transmission?
Environment (weather, housing, food), agent (infectivity, survival and pathogenicity) and host (sex, age, genotype, behaviour)
What are the layers of the heart wall?
Epicardium (visceral pericardium), myocardium (layer of contracting cardiomyocytes) and endocardium (continuous with endothelium and lines valves and chambers)
What is an epidemic, pandemic, incidence and prevalence
Epidemic - outbreak of infection above expected levels. Pandemic - epidemic that affects more than one country. Incidence - probability of infection (number of new cases per population at risk in given time). Prevalence - proportion of population affected by infection
What are the features of epidural and subdural bleeds on imaging?
Epidural - lens shaped Subdural - lens shaped but more diffuse/spread out
What cells are found in blood and what are their functions?
Erythrocytes (carriage of O2/CO2), leucocytes (immune response) and platelets/thrombocytes (haemostasis)
What are essential, conditional essential and non-essential AAs?
Essential AAs are those that can't be synthesised by the body so must come from diet. Conditional essential AAs can be synthesised but not enough under certain conditions. Non-essential AAs are synthesised by the body
Describe the steps of alcohol metabolism, how does disulfiram work and how is the Asian population different WRT alcohol metabolism?
Ethanol --(alcohol dehydrogenase/catalase/CYP450)--> acetaldehyde (toxic) Acetaldehyde + NAD --(acetaldehyde dehydrogenase)--> acetate + NADH Acetate + ATP + CoA --> Acetyl CoA + AMP + PPi Disulfiram inhibits acetaldehyde dehydrogenase so causes build-up of toxic acetaldehyde. 30-50% Asians have deficiency of acetaldehyde dehydrogenase
What is the function of the lateral compartment of the leg, what are the muscles and what is the innervation?
Eversion (superficial peroneal nerve) Muscles - fibularis longus and fibularis brevis
What diseases/conditions can evoked muscle action and recording sensory nerve volley in digits show?
Evoked muscle action - carpal tunnel entrapment and myasthenia gravis Sensory nerve volley - peripheral demyelination
What is oedema, what are symptoms, where does systemic oedema first affect and how can this be distinguished from increased venous pressure during standing?
Excess fluid retention in interstitial compartment. Symptoms include swollen/puffy ankles, feet or legs and shiny, stretched or red skin. Systemic oedema first affects lower regions and can be distinguised by applying pressure (pitting oedema)
What do extrapyramidal and pyramidal tracts do and what does each control?
Extrapyramidal - carry motor neurons from brainstem to spinal cord and controls involuntary/automatic control of musculature for muscle tone, balance, posture and locomotion Pyramidal - carry motor neurons from cortex to brainstem or spinal cord and is for voluntary movements of body and face musculature
Describe the extrinsic innervation of the GIT
Extrinsic innervation from vagus nerve that innervates mouth to transverse colon. Central terminals enter brainstem and synapse to neurons in NTS
What are the movements performed by the eye, where do the rectus muscles originate from and where do the superior/inferior oblique muscles run?
Eye can perform abduction/adduction, depression/elevation and intorsion/extorsion. Rectus muscles originate from common tendinous ring in back of orbit. Superior oblique runs superior-medially then through trochlea (tendinous hook) to insert on posterior eyeball. Inferior obllique runs on medial orbit then back to insert on posterior eyeball
What is F-1,6-BP converted to, how are they interconverted and what product is needed for further steps?
F-1,6-BP --> dihydroxyacetone phosphate and glyceraldehyde-3-phosphate using aldolase. Interconverted using triose phosphate isomerase. Glyceraldehyde-3-phoshate necessary for further steps
What is the 3rd step of glycolysis and what factors control this enzyme?
F-6-P --> F-1,6-BP using phosphofructokinase 1. Tightly controlled allosterically, sensitive to substrates (high ATP:ADP ratio inhibits PFK1), citrate inhibits activity and F-2,6-BP from PFK2 stimulates activity. PFK2 acts as regulatory enzyme that allows for greater sensitivity to regulation by hormones
Describe ATP synthase
F1-F0 ATP synthase converts PMF to ATP by C ring rotation caused by H+ diffusion which causes ATP sunthesis in beta section
Describe the mucosal phase of lipid digestion
FAs and monoglycerides enter enterocyte by simple diffusion, reassembled into triglycerides and packaged in chylomicrons
What oxidises FAs, where does it occur (and what is the exception), and what are the products of b-oxidation?
FAs oxidised by acetyl CoA dehydrogenases in mitochondrial matrix via b-oxidation. Occurs in most tissues with mitochondria (apart from the brain) and forms NADH and acetyl CoA that feed into the TCA and ETC to produce ATP
What is familial hypercholesterolaemia, symptoms and treatment?
FH is a genetic defect reducing number of functional LDL receptors (mainly in liver). Symptoms - hypercholesterolaemia, tendon xanthomas and premature CHD. Treatment - statins, diet modifications and bile acid binding resins
Where do afferents from face travel and enter, where do fibres run and where do face afferents ends?
Face afferents travel in cranial nerves and enter trigeminal nucleus. Post-synaptic fibres decussate and run with medial lemniscal fibres to end in VPM nucleus (thalamic relay for facial sensation)
What is the function of the red nucleus and what are the signs of a lesion above/below RN?
Facilitates arm flexors so lesion above RN causes decorticate rigidity (arm flexion and leg extension in response to pain) and lesion below RN causes decerebrate rigidity (increased extension to stimulus as no RN flexor facilitation)
What are neurotrophic factors?
Factors released by innervated cells that are taken up by nerve terminals to be transported retrogradely to cell body to promote neuronal growth and survival
What is the consequence of having a faster feedback response and in what diseased population are falls more common?
Faster feedback resposne allows faster corrective muscle action so improves balance and agility. Falls more common in patients with demyelinating diseases as reflex arcs are slower
What are the fat soluble and water soluble vitamins, how are they absorbed?
Fat soluble - A, D, E and K. Absorbed with lipids as dissolve in micelles and chylomicrons. Water soluble - B and C. Follow flux of H2O from gut lumen
How are fat and water soluble vitamins absorbed?
Fat soluble vitamins packaged in micelles and chylomicrons and absorbed with lipids. Water soluble vitamins follow flux of water from gut lumen through mucosa
How are fat and water soluble vitamins stored and what can they cause in excess?
Fat soluble vitamins stored in adipocytes so excess can be toxic. Water soluble vitamins not stored so excess is excreted in urine
What are fat stores and glycogen and where are they found?
Fat stored in white adipose tissue and is stored long term with high energy density. Glycogen in liver and muscle for medium term storage
How do bacteria obtain nutrients from host?
Fatty acids and sugars are abundant, but can produce chelating agents with high Fe affinity
What is normal posture when standing at rest?
Feet are slightly apart, hip and knee extended and centre of pressure in front of ankle and knee and just behind hip and ear
Where is surface anatomy of the femoral artery, where is the sciatic nerve and what does the inguinal ligament connect?
Femoral artery - midpoint of ASIS and pubic symphysis Sciatic nerve - halfway between greater trochanter and ischial tuberosity Inguinal ligament connects pubic tubercle and ASIS
What does the femoral artery supply, what does it give off (what does this supply) and where does femoral artery become popliteal artery?
Femoral artery supplies anterior thigh. Gives off profunda femoris (supplies posterior thigh) which gives off lateral and medial circumflex arteries. Femoral artery becomes popliteal artery when it passes through adductor hiatus
What is nystagmus and what are the different phases?
Form of VOR caused by continuing rotation of fluid in semi-circular canals Slow phase of nystagmus follows movement of fluid so fast phase is against direction of rotation
What does the femoral nerve innervate, what causes femoral nerve palsy, what does this cause and what does obturator nerve innervate?
Femoral nerve innervates anterior thigh. Femoral nerve palsy caused by compression (treatment for congenital hip dysphagia), pelvic fractures and anterior hip fractures. Causes quadricep paralysis and sensory loss to anterior thigh and medial leg. Obturator nerve innervates adductors/medial thigh compartment
Where is the femoral triangle found, what are its superior, lateral and medial borders and what structures are found within it?
Femoral triangle found between between anterior and medial compartments. Superior - inguinal ligament (ASIS to pubic tubercle), lateral - sartorius, medial - adductor longus. Contains femoral nerve, femoral artery, femoral vein, emtpy space and lymphatics (lateral to medial - NAVEL)
Briefly describe the structure of the femur and humerus
Femur - head and neck (neck most susceptible part to fracture) Humerus - head, anatomical neck (slight narrowing below head), surgical neck (below tubercles and part most susceptible to fracture) and greater (lateral) and lesser (anterior) tubercles
What are structural characteristics of glomerular capillaries and how can this be used to show disease?
Fenestrated (gaps in endothelium) capillaries with podocytes (form filtration mechanism). Inflamed podocytes allow excess protein filtration so proteinuria is a sign of glomerular inflammation
What is the structure of choroid capillaries, how is CSF flow regulated and what is a feature of CSF flow?
Fenestrated to produce ultrafiltrate of blood Regulated by ependymal cells to 500ml/day and flow is pulsatile in phase with HR
What are the first line therapies (preventative) and medical therapy for stable angina?
First line is lipid-lowering drugs and medical therapy are nitroglycerin, beta blockers and ACEi
What arm muscles cause flexion, extension, pronation and supination?
Flexion - biceps brachii, brachialis Extension - triceps brachii Pronation - pronator teres and pronator quadratus Supination - supinators (attaches to ulna then wraps around to attach to radius) and biceps brachii
What muscles cause flexion, extension, lateral flexion and rotation of back?
Flexion - rectus abdominis, psoas major Extension - paraspinals, gluteus maximus Lateral flexion - SCM, rhomboids, internal/external oblique, quadratus lumborum and gluteals Rotation - paraspinals, internal/external oblique and SCM
What movement do the flexor muscles cause in the hands and what muscles do they include?
Flexor muscles close the hand and include flexor digitorum profundus/superficialis and flexor pollicis longus
How can flow velocity be measured?
Flow = cross section area x velocity. Doppler ultrasound, transoesophogeal doppler (for thoracic aorta) or transthoracic impedance cardiography (non-invasive and measures changes in electrical conductivity of thorax)
What is ventilation and how does movement of air occur?
Flow of air in and out of respiratory system to deliver air to the alveoli for gas exchange. Air movement occurs due to pressure differences (moves from high to low pressure)
How do immune cells trigger an immune response?
Foeign molecule binds to receptor, signalling cascade initiated then gene transcription that produces effector molecules (cytokines or antibodies)
What is a special adaptation of the foetal skull, what do they allow, where is the metopic suture found and what are the main areas that develop in the foetal skull into future structures?
Foetal skull has fontanelles to allow brain growth and flexibility during childbirth. Metopic suture found in frontal bone. Anterior fontanelle (future bregma), posterior fontanelle (future lambda), future pterion and future asterion
What is the function of the intrinsic foot muscles and where are they found?
For precise movements and in sole of foot between calcaneus and base of metatarsals or toes. Contract and relax to respond to dynamic changes
How is the pulmonary circulation different in a foetus and how does this change at birth?
Foramen ovale shunts blood from right heart to left heart. Ductus arteriosus shunts blood from pulmonary artery into aorta. Both shunts close shortly after birth. Highly hypoxic lung tissue causes alveolar vasoconstriction. When the baby first breathes, hypoxia decreases so alveolar vasodilation which decreases pulmonary vascular resistance so that pulmonary blood flow equals CO
What does the foramen spinosum hold and what can damage to pterion cause?
Foramen spinosum (quite small and more visible inferiorly) holds middle meningeal artery so damage to pterion can cause extradural haematoma due to damage to middle meningeal artery
What is inotropy, what does it effect and what has +ve inotropic effects?
Force of heart contractility. Increased inotropy decreases residual volume so increases SV. Increased by hypercalcemia, beta adrenergic agonists, drugs that stimulate myocardial Ca2+ entry (levosimendan), cardiac glycosides (digoxin), insulin and glucagon
What is found in the foregut, midgut and hindgut and what are the blood supply to each?
Foregut (coeliac trunk) - oesophagus, stomach, superior duodenum, liver, pancreas and spleen Midgut (superior mesenteric artery) - distal duodenum, small and large intestine up until splenic flexure Hindgut (inferior mesenteric artery) - splenic flexure, descending and sigmoid colon, rectum and upper anal canal
What is found in the foregut, midgut and hindgut, what is the blood supply to each and what mesogastrium does each develop with?
Foregut (coeliac trunk, develops with dorsal and ventral mesogastrium) - stomach, 1st part of duodenum, liver, spleen, pancreas Midgut (SMA, develops with dorsal mesogastrium) - distal duodenum, small intestine and large intestine up to splenic flexure Hindgut (IMA, develops with dorsal mesogastrium) - splenic flexure, descending colon, sigmoid colon, rectum, upper anal canal
What do thenar and hypothenar muscles form and what are they innervated by?
Form thenar and hypothenar eminences. Thenar (median nerve) allows opposition and hypothenar innervated by ulnar nerve
Where is the common carotid pulse found, what does a pulse indicate, where does the common carotid bifurcate and what is the innervation to the carotid body and sinus?
Found at anterior border of SCM at level of thyroid cartilage. Pulse indicates systolic bp at least 40mmHg. Bifurcates at superior border of thyroid cartilage. Carotid body (chemoreceptor, CN IX and CN X) and carotid sinus (baroreceptor, CN IX)
What is fibronectin?
Found circulating in plasma or in body fluids and ECM. Binds cells (integrins) and ECM (collagen) and has role in cell attachment, matrix organisation and guiding migration
Where are stretch receptors found, when/why do they fire and how do they work?
Found in bronchi and bronchioles. Fire in response to distension to prevent lung over-inflation and damage. At end of inspiration, afferents in vagus nerve to respiratory centre in pons/medulla which inhibit phrenic nerve to dipahragm
Where can carcinomas be found and what are the names of carcinomas based on site?
Found in lining (stratified squamous to form squamous cell carcinoma) and glandular epithelium (simple cuboidal or simple columnar to form adenocarcinoma)
What are oesophageal varices?
Found in lower oesophagus and are indicative of increased pressure in portal system or liver disease
Where are the hip adductors found, what do they attach to and what nerve innervates them?
Found in medial compartment of thigh (innervated by obturator nerve). Attach to pelvis and distally to linea aspera
Where is the pituitary gland found and what are anatomical features of it?
Found in pituitary fossa in sphenoid below hypothalamus. Has anterior and posterior lobes and pituitary stalk/infundibulum
What is ACHE and how can it be inhibited?
Found in synaptic cleft and breaks down ACH. Inhibited with organophosphate nerve agents (eg. sarin) or medically with neostigmine/physostigmine
Where are central chemoreceptors found, what are they sensitive to and how is this molecule formed?
Found in ventral surface of medulla oblongata and sensitive to changes in CSF pH/[H+]. Inspired CO2 diffuses through BBB into CSF where it reacts with H2O to form carbonic acid which creates HCO3 and H+ using carbonic anhydrase
Where is the hypothalamus found, what is found directly below it and how is the pituitary gland connected to the hypothalamus?
Found on anterior-most part of 3rd ventricle. Optic nerve and optic chiasm found directly below it and pituitary gland in midline connected via pituitary stalk
Where does fractured NOF occur, how does it present and how can it cause avascular necrosis?
Fractured NOF offurs in femoral neck, across the neck (most common) or in trochanteric region. Presents as shortened leg with lateral rotation of foot and disrupted Shenton's line on XR. Can cause avascular necrosis due to disruption of acetabular branch of obturator femoris or retinacular arteries (branches of medial/lateral circumflex arteries from profunda femoris)
What are the 4 stages of food movement through digestive system?
Fragmentation - in oral cavity and stomach aided by saliva. Digestion - stomach and duodenum using pancreatic enzymes, bile salts and brush border enzymes. Absorption - jejunum and ileum where enterocytes absorb nutrients. Elimination - colon and anal canal where liquid residue passed to colon where water absorbed then solid faeces are expelled
How are free FAs transported in the blood, where are they oxidised and what are the steps of FA transport into the mitochondria?
Free FAs are transported bound to serum albumin and are oxidised in the mitochondria Step I - add CoA to FA using acyl CoA synthetase and ATP to form fatty acyl CoA Step II - fatty acyl CoA transported into mitochondria using CPT1 (adds carnitine)/carnitine shuttle Step III - fatty acyl carnitine transported into matrix using translocase and carnitine removed by CPT-II
What is sacral outflow, what does it innervate and how can it be damaged?
From S2-S4 via pelvic splanchnic and innervates distal colon, rectum, pelvic viscera and external genitalia. Can be damaged through colorectal cancer surgery
What are peroxisomes and what diseases can they cause?
From rER, detoxification of alcohol, H2O2 and free radicals and metabolism of fatty acids. Zellweger syndrome - faulty peroxisomes can't break down lipids so cells full of long chain fatty acids
What is the parasympathetic supply to the lungs and what does this do?
From vagus nerve containing afferents (detects stretch during inspiration) and efferent (produce bronchoconstriction and stimulates bronchial mucus secretion)
Give an example of how the RF mediates a somatic reflex
Frontal eye field (FEF) excitation stimulates paramedian pontine RF (PPRF) and allows horizontal eye movement by activating CN VI and inhibiting CN III (inhibits by MLF connection)
What are the roles of the different parts of the brain
Frontal lobe - problem solving, emotions, reasoning. Parietal lobe - 1y somatosensory cortex. Occipital - visual and colour perception. Temporal - speech and hearing. Cerebellum - coordination of complex movement. Brainstem - autonomic control
How is fructose metabolised?
Fructose --(fructokinase)--> fructose 1P --(aldolase B)--> dihydroxyacetone phosphate + glyceraldehyde --> glyceraldehyde phosphate
What causes fructose intolerance, what accumulates in the liver and kidneys what does it inhibit and what happens in severe cases?
Fructose deficiency caused by deficiency in fructose aldolase so fructose 1P accumulates in liver and kidneys which inhibits glycogenolysis and gluconeogenesis, resulting in hypoglycaemia. Hepatic and renal failure can occur in severe cases
What is the effect of hypoxia on alveolar blood vessels?
Hypoxia causes local constriction of alveolar blood vessels to divert blood away from poorly ventilated, hypoxic areas
What are the divisions of the stomach, where are the curvatures found and what are rugae?
Fundus, body, atrum and pylorus. Lesser curvature on medial side and greater curvature on lateral side. Rugae are folds inside stomach
How does holding from eqm create energy?
Further from eqm, more energy stored. Uses electrochemical gradient and mitochondria use this to create ATP from proton motive force (PMF) of H+ in intermembrane space
What forms spinal nerves and what happens if dorsal roots are severed between dorsal root ganglion and spinal cord?
Fusion of ventral and dorsal roots. If severed between DRG and spinal cord, causes spinal paralysis as dorsal root can't regenerate into spinal cord
What is the 2nd step of glycolysis and why is this done?
G-6-P --> F-6-P using phosphoglucose isomerase. This step is necessary as it makes further steps easier
How is glycogen synthesised from G-6-P, what breaks down glycogen and when is this enzyme active?
G-6-P --> G-1-P G-1-P + UTP --> UDP-Glucose + Ppi (pyrophsophate) --> 2Pi UDP-Glucose --(glycogen synthase)--> glycogen + UDP Broken down into G-1-P using glycogen phosphorylase which is active when phosphorylated
What are muscarinic receptors/MACHRs?
G-protein-coupled receptors that activate ionic channels via 2nd messenger cascade. Cause hyperpolarisation of myocardium. MACHRs in pancreatic acinar cells lead to secretions
What are the stages of the cell cycle and what occurs in each stage?
G1 (cellular contents apart from chromosomes replicated), S (DNA duplicated), G2 (cell checks duplicated chromosomes for errors and makes repairs), M (cell divides into 2 identical daughter cells) and G0 (in non-dividing, fully differentiated cells or stem cells)
Describe GABA receptors
GABAa receptors permeable to Cl influx to allow IPSP and activation also makes membrane more leaky to current to inhibit neuronal activity
What are proteoglycans?
GAGs bonded to a protein unit. Synthesised in rER and delivered by exocytosis. Bind to water to form gel that fills space and can resist compressive force, allow rapid diffusion of nutrients, hormones and metabolites
What is GFR and it's normal rate. After what age does GFR start to decrease and how is renal plasma flow calculated?
GFR is amount of plasma filtered by the glomerulus per minute (normally 120-125ml/min). Usually starts to decrease after age 40. RPF = 1.25 x (100 - haematocrit %)
Why are EPO secreting cells in the kidney?
GFR is autoregulated and renal blood flow and metabolic rate don't vary so constant O2 consumption. Therefore, pO2 in interstitium is a measure of O2 delivery to kidney and O2 carrying capacity
What movement does the glenohumeral joint allow, how does it allow a greater range of movement, what is found on the inferior fold of the synovial joint and where are the brachial plexus and axillary nerve found in relation to the GH joint?
GH joint allows lateral/medial rotation, extension/flexion, adduction/abduction and allows a greater range of movement as it only accomodates 1/3 of the head of humerus. Inferior fold of the synovial joint has a Lax capsule that allows further movemetn. Brachial plexus found anterior to GH joint and axillary nerve (innervates deltoid muscles) found inferiorly
What are the causes of GORD?
GORD can be caused by increased frequency of TLOSRs, weakened LOS, hiatal hernia, hypersensitivity of oesophageal pain sensing nerves and bile/non-acid components of gastric juice
What is GORD, what is it associated with, what can it lead to and how is it treated?
GORD is retrogade flow of stomach contents from fundus to distal oesophagus due to relaxation of LOS. Associated with obesity, gastroparesis and stress. Can lead to oesophagitis, Barrett's oesophagus and ulcer formation. Treated using OTC medications (alginates and antacids) or prescription treatments (PPIs)
How does GTN work, what is the effect of venodilation on the heart and what are GTN side effects?
GTN converted to NO using aldehyde dehydrogenase --> stimulates cGMP formation from GTP --> activates phosphatase that dephosphorylates myosin light chain --> vasodilation of CA and veins. Venodilation --> decreased preload --> decreased EDV --> decreased contractility --> decreased myocardial oxygen demand GTN side effects include reflex tachycardia, dizziness and headache
What is the golgi tendon organ and what is its function?
GTO is proprioceptor in muscle tendons sensitive to tension. Has disynaptic connection to own motor neurons but interneuron is inhibitory. If tension too high (which may cause muscle damage), GTO is activated and inhibits further contraction
What is galactosaemia type I, what does the enzyme defect result in, what do children with this disease develop and how is it treated?
Galactosaemia type I is a deficiency in galactose-1-phosphate uridyl transferase (converts galactose 1P --> glucose 1P) so child can't use galactose portion of lactose. Results in accumulation of galactose 1P and galactose in tissue and blood. Children develop mental retardation, cataracts, hypoglycaemia and acidosis. Treated using galactose-free diet
What are the functions of the respiratory system and what are in the URT and LRT?
Gas exchange and acid-base balance. URT - nasopharynx, oropharynx and larynx. LRT - conducting airways (non-respiratory), alveoli and terminal bronchioles (respiratory)
What happens to gas velocity as total cross sectional area of airways increases and why is this important?
Gas velocity decreases. Decrease in velocity and small increase in volume important as gaseous diffusion important part of gas exchange
What molecules activate the stomach proton pump and what molecules deactivate it?
Gastrin, histamine and ACH activate the proton pump and somatostatin and prostaglandins inhibit it
What is the connection between stomach and spleen, where is the greater sac found and what is the epiploic foramen?
Gastrosplenic ligament connects stomach and spleen. Greater sac found on anterior abdominal wall and epiploic foramen allows passage between greater and lesser sacs
When are humans germ-free and where are normal, permanent microbiata colonies found?
Germ-free in-utero. Found in nose, mouth, skin, lungs, gut, stomach and vagina/urethra
What is the function of the vertebral curvatures and what parts of the vertebral column give flexibility?
Give extra flexibility and shock-absorbing resilience Flexibility of IVDs is passive and limited but flexibility from curvatures is dynamic/changeable
What are prodrugs?
Given in inactive form and require chemical/enymatic transformation to release active form. Converted to active drug on 1st pass metabolism
What info does pulsations of IJV give, why is there JVP and when does this rise?
Gives info about right atrial pressure (normally 2cm). JVP due to no valves in brachiocephalic vein or SVC so blood can travel up vein at 45 degrees. Rises in mitral valve disease, raised pulmonary circuit pressure or right sided heart disease
What receptors are foud in the dermis of glabrous and hairy skin and what do they respond to?
Glabrous skin has a variety of receptors that respond to pressure, light touch and vibration Hairy skin has hair follicle receptors (hybrid of free and encapsulated endings) that respond to hair displacement
What structure deepens the glenoid fossa, how can this be torn and what inserts into this?
Glenoid labrum (fibrocartilaginous disc) deepens glenoid fossa. Can be torn due to shoulder dislocation. Long arm of biceps inserts into glenoid labrum
What are the consequences of MCA stroke?
Global aphasia and sensorimotor loss on contralateral face, upper limb and trunk
What types of cells are found in the carotid bodies?
Glomus type I (chief) and glomus type II (sustentacular) cells. Type I cells release NT that stimulate sensory endings of glossopharyngeal efferents that project to medullary respiratory centres. Type II cells resemble glia and act as supporting cells
Where is glucokinase found, what is different about it compared to hexokinase what controls its location and when is this activated?
Glucokinase found in liver/pancreas and has high Km so beta cells in pancreas can act as glucose level sensors. It isn't sensitive to feedback inhibition. Location controlled by glucokinase regulatory protein (GKRP). With low blood glucose, GKRP holds GK in the nucleus and prevents activity
How is insulin secreted and what are the phases of insulin release?
Glucose --> G-6-P --> pyruvate. Pyruvate used for ATP synthesis via TCA and ETC so ATP:ADP ratio increases. K(ATP sensitive) channels close so membrane depolarises and Ca VGCs open to increase intracellular [Ca] which stimulates insulin secretion
How do b-cells respond to increased [glucose]?
Glucose enters cells via GLUT1 and GLUT3. Glucokinase (high Km) acts as a sensor as is only active at high [glucose] to allow insulin secretion
Where and how is G-6-P dephosphorylated and what stimulates glycogen breakdown in the liver?
Glucose-6-phosphatase. Stimulated by glucagon via phosphorylation of glucose-6-phosphatase
Describe the stages of the urea cycle and how is it controlled?
Glutamate --(glutamate dehydrogenase)--> NH3 + CO2 --(CPS using ATP)--> caramoyl phosphate Carbamoyl phosphate feeds into cycle as added to ornithine to form citrulline. Aspartate added to citrulline to form argino-succinate which is converted to arginine (creatine released). Arginine converted to ornithine by releasing urea CPS under control from N-acetyl glutamate (glutamate + acetyl CoA --> N-acetyl glutamate + CoA)
What are the ways that glutamate can be metabolised?
Glutamate can be transaminated into alanine using a-ketoglutarate and pyruvate. Can be directly converted into a-ketoglutarate and release NH4. Can also be converted into glutamine by adding NH3 (glutamine used to transport NH4 to kidney)
What receptors does glutamate use and how do benzodiazepines work?
Glutamate uses ionotropic (excitatory) and metabotropic (inhibitory) receptors . Benzodiazepines cause GABAa activation so increased Cl- entry and hyperpolarisation (sedatives, sleep-inducing and anxiolytics)
What are the roles of glutamine?
Glutamine used in skeletal muscle, kidney (substrate for gluconeogenesis and formation of NH3), CNS (shuttle for glutamate maintenance) and immune cells (fuel and enhances T lymphocyte response to infection and supports phagocytosis)
What is the function of gluteus maximus (and neurovascular supply), what is the function of gluteus medius/minimus and what causes contralateral hip drop?
Gluteus maximus (inferior gluteal nerve) for hip extension and external rotation Gluteus medius/minimus for hip adduction and stabilisation so weakness can cause contralateral hip drop
What happens to glyceraldehyde-3-phosphate and how does this create ATP?
Glyceraldehyde-3-phosphate -- (glyceraldehyde-3-phosphate dehydrogenase)--> 1,3-biphosphoglycerate --(phosphoglycerate kinase)-> 3-phosphoglycerate. GPDH dehydrogenates GAP by transferring H to NAD and also adds phosphate from cytosol to oxidised GAP to form BPG. Phosphate then transferred from BPG to ADP using phosphoglycerate kinase
What does glycerol come from and what does this enter glycolysis/gluconeogenesis as?
Glycerol comes from breakdown of TAGs and enters as dihydroxyacetone phosphate in middle of processes
Where does glycerol come from and how can it feed into glycolysis?
Glycerol comes from breakdown of fat, Metabolised in liver to form dihydroxyacetone phosphate. Glycerol --(glycerol kinase)--> glycerol-3P --(NAD-->NADH)--> dihydroxyacetone phosphate
What is the function of HDLs, what apo do they contain and how do they take up cholesterol from cells?
HDLs exchange components with other lipoproteins and transport cholesterol from tissues to the liver for disposal (via bile). Mainly contains apoA-I and take up cholesterol from other cells using scavenger receptors that transfer cholesterol from cell membrane to HDL via ABCA1 transporter
What does glycogen breakdown in muscle cells feed into, what happens to products of anaerobic respiration and what stimulates glycogen breakdown in muscles?
Glycogen breakdown in muscles feeds into glycolysis in that cell only. Lactate from anaerobic respiration recycled using Cori cycle and glycogen breakdown in muscles stimulated by phosphorylation of glycogen phosphorylase by contraction and adrenaline
Where is glycogen stored and what are the functions in different sites, what is the function of glucogen and how is it well-adapted?
Glycogen stored in liver (for maintaining blood glucose) and muscles (for short, intense activity). Acts as a readily mobilisable glucose store. Well-adapted as less osmotically active and highly branched so allows multiple sites of breakdown/synthesis
What is needed for glycogen to form, how does it branch and where is glycogen broken down/synthesised?
Glycogenin protein primer needed for glycogen synthesis. Branches added using branching enzyme that adds 1,6 branches every 12-14 residues. Glycogen broken down/synthesised from furthest part from glycogenin
What are the different membrane lipid components?
Glycophospholipids (phosphatidyl-inositol, phosphatidyl-ethanamine, phosphatidyl-choline, phosphatidyl-serine), sphingolipids with serine linker (sphingomyelin, cerebroside and GM1-ganglioside)
What are T cell receptors (TCRs) and why are they diverse?
Glycoprotein dimers with alpha and beta chains, variable and constant region, transmembrane and stalk segments. Diverse due to somatic DNA recombination of alpha and beta chain loci
What are GAGs?
Glycosaminoglycans (linear chains of disaccharides). Hyaluronic acid in joints and resists compressive forces and lubricates. Good for cell migration so important in wound healing
What is the gold standard for measuring GFR and what is used in clinical practice?
Gold standard is inulin as it is completely filtered and not reabsorbed. Creatinine clearance used instead as creatinine is produced from break-down of creatine phosphate. Also secreted into PCT so overestimates GFR by 10-20%
What is the function of the Golgi?
Golgi modifies and tags proteins from rER and transports them in vesicles to the cell or for exocytosis
What is an end-plate potential and when is AP triggered?
Graded depolarisation depending on amount of ACH released Triggered when depolarisation meets threshold (about -40mV)
What are the superficial veins of the lower limb?
Great (anterior) and small (posterior) saphenous veins
What are the superficial veins of the lower limb and why are they at risk of becoming varicose?
Great (runs medial side and drains into femoral vein) and small saphenous (runs posterior side and drains into popliteal vein) veins. At risk of becoming varicose as standing upright increases pressure in lower limb veins
What are the branches of the facial nerve and what do they provide?
Greater petrosal nerve - splits and runs superiorly to innervate lacrimal gland with parasympathetic fibres Chorda tympani - runs into infratemporal fossa to supply special sensory to anterior tongue and provide parasympathetic fibres to sublingual/submandibular glands Motor portion - runs out of stylomastoid foramen and splits into 5 branches (temporal, zygomatic, buccal, marginal mandibular and cervical, 'To Zanzibar By Motor Car') that innervate muscles of facial expression
Where are grey/white matter found?
Grey matter (unmyelinated cell bodies) on outside and white matter (myelinated axons) on inside
How is white/grey matter arranged in the spinal cord and what features do the white and grey matter have?
Grey matter is centralised and surrounded with white matter. Grey matter has anterior, lateral and posterior horns of grey. White matter has anterior, lateral and posterior funiculi
Where are gut microbiotia found, what are imbalances linked with and what diseases do they mediate?
Gut microbiota mainly found in colon but some also found in small intestine. Imbalances linked with neurodegeneration, obesity and inflammation. Have an important role in mediating IBS and IBD
Where does H pylori survive, what enzyme does it have, how does it survive and what does process this cause?
H pylori survives in the stomach and duodenum. Has urease enzyme that converts urea + H2O --> NH3 + CO2. Tunnels through mucus layer --> urease enzyme produces NH3 which neutralises pH --> recruits more H pylori --> mucosal damage as exposed to pepsin and H+
What is the haemoglobin buffer system?
H+ + Hb <--> HHb. Takes up H+ in tissues and exchanges for O2 in lungs where acid blown off as CO2
How is HMG CoA synthase controlled?
HMG CoA synthase controlled by post-translational modification (acetylation) and transcriptinally (by FOXA2 (stimulated by glucagon and inhibited by insulin))
HMG CoA synthase controlled by post-translational modification (acetylation) and transcriptinally (by FOXA2 (stimulated by glucagon and inhibited by insulin))"
HMG CoA synthase controlled by post-translational modification (acetylation) and transcriptinally (by FOXA2 (stimulated by glucagon and inhibited by insulin))"
What are symptoms of schizophrenia and what is it caused by?
Hallucinations/delusions, paranoid behaviour, disruption of social contact and withdrawal from family/friends Hyperactivity of ventral striatum to cause increased dopamine release
What are infection control techniques?
Hand hygiene, PPE (gowning, gloves, masks), covering cough, environmental cleaning
What forms the hard and soft palate, what happens to the soft palate during swallowing, what innervates soft palate muscle, what is found in the midline and what are the two arches?
Hard palate formed from maxilla and palatine bones. Soft palate composed of muscles covered by mucous membrane. Elevates during swallowing to prevent food entry into nasal cavity and is innervated by vagus nerve. Uvula found in midline and palatoglossal (anterior) and palatopharyngeal (posterior) arches
Describe the structure of the sympathetic efferent system
Has 2 neurons between spinal cord and smooth muscle. Preganglionic fibres are small myelinated Ab axons and postganglionic are unmyelinated C fibres
What is cholesterol, what is it's function in the membrane and what is made from it?
Has OH head (associates with glycerophospholipid head), steroid rings and non-polar hydrocarbon chain (both interact with glycerophospholipid acyl chain). Modulate membrane fluidity by increasing density of glycerophospholipid bilayers so decreasing fluidity but decreasing density of sphingolipid membranes so increasing fluidity. Can make vit D in skin, cortisol and aldosterone in adrenal gland, testosterone in testes
What are G protein coupled receptors?
Has a 7 transmembrane spanning domain structure and linkage with G protein complex. When ligand binds, conformational change that activates G protein that activates 2nd messenger using GTP energy that activates downstream signalling
What is the function of the hypothalamus?
Has a function in homeostasis (sleep-wake cycle, reproduction, temeprature, water balance, body weight) and is the link between senses and activation of the ANS
What is a result of the metabolism of the eye?
Has a very high O2 requirement as photoreceptors are very metabolically active
What are the features of the lateral ventricle and what is the passage of CSF flow through ventricles?
Has anterior, posterior and inferior horns Lateral ventricle --> interventricular foramen --> 3rd ventricle --> cerebral aqueduct --> 4th ventricle
What is the structure of the temporal bone and what structure does it house?
Has thin squamous part, mastoid process, styloid process, zygomatic process, internal/external acoustic meatus and petrous part. Houses middle and inner ear
Why does the immune system have variable energy demand and how are ROS made?
Has variable energy demand due to phagocytosis, anabolism of immune mediators and formation of ROS (made using NADPH from conversion of G-6-P --> riboses and malate --> pyruvate) O2 --(NADPH oxidase)--> O2- --(superoxide dismutase)--> H2O2 --(myeloperoxidase)--> OCL-
What are the inputs to LMNs?
Have inputs from descending tracts via UMN, local interneurons and local sensory fibres via reflexes
What is the structure of lymphocytes, what is their lifespan and the different types?
Have large nucleus and little cytoplasm. Lifespan of 1 week - 100 years. B cells, T cells and NK cells
What is a feature of monosynaptic reflexes and what are homonymous reflexes?
Have no interneurons and are hard to consciously suppress. Homonymous reflexes where stretch of muscle activates contraction of same muscle
What are the features of cartilaginous joints and what are the different types?
Have no synovial cavity and hold together articulating bones with cartilage (fibro or hyaline). Either symphysis (fibrocartilage in pubic symphysis and IV discs) or synchondrosis (hyaline cartilage in epiphyseal growth plates)
What is percent saturation, how is it measured, what is a healthy O2 and what is hypoxaemia?
Hb binding proportion. Measured using pulse oximeter. Healthy O2 - 96-99% but should be >94% and hypoxaemia is <90%
What is special about Hb, what is the normal shape of an RBC and why do mature RBCs not have nuclei/mitochondria?
Hb can rapidly and reversibly bind to oxygen without becoming oxidised. Normally biconcave shape without nucleus/mitochondria as they would be damaged by high O2 levels
What are the functions of the auditory system?
Hearing (distinguishing different sounds and localisation) and language (production and comprehension)
What is HF, what symptoms does it cause and how can it cause oedema?
Heart unable to pump blood properly. Symptoms include breathlessness, fatigue and swollen ankles/legs. Causes oedema as raised venous pressure reduces reabsorption
How does heavily metabolising tissue affect the local Hb curve?
Heavily metabolising tissue produces lots of heat and CO2. High heat shifts Hb dissociation curve right so more O2 released at given pressure. CO2 dissolves to decrease pH which also shifts curve right (Bohr shift)
What are the sub-divisions of the stance phase?
Heel strike - foot inverted and dorsiflexed as heel contacts on lateral side Loading response - foot in full contact and ankle rocker begins Midstance - body weight over planted foot Terminal stance - heel lifted off ground (everted and plantarflexed) so body weight advances Pre-swing - lower limb positioned to quickly swing forward and weight transferred to other limb
What is Her's disease, what do fasting children with this disorder have and how is it treated?
Her's disease is a deficiency in liver glycogen phosphorylase so prevents liver making its glycogen stores available to the rest of the body. Fasting children have hypoglycaemia and hepatomegaly. Treated by providing starch several times per day
What are hernias, what are the most common abdominal hernias, when does they become a surgical emergency and where do femoral hernias occur?
Hernias are protrusions of peritoneum and viscera through opening or weakness. Most common abdominal hernias are inguinal (75%) and become surgical emergency if blood supply cut of at hernia opening. Femoral hernias occur in femoral canal next to femoral arteries and vein
How can heroin, cocaine, nicotine and alcohol addictions be treated?
Heroin - methadone as substitute Cocaine - antibodies against cocaine Nicotine - NRT (eg. patches) to decrease toxicity associated with addiction Alcohol - disulfiram (blocks metabolism) induces nausea
What are nicotinic antagonist examples?
Hexamethonium (for ganglionic NACHRs and antihypertensive). Pancuronium - longer-term depolarising block for lethal injection. Tubocurarine - skeletal muscle relaxation/paralysis
What enzyme forms G-6-P and what is this enzyme sensitive to?
Hexokinase phosphorylates glucose --> G-6-P and is sensitive to feedback inhibition so increased [G-6-P] inhibits HK and also GLUT transporter
How are LDL and HDL linked to CVD and what effect does alcohol consumption and regular aerobic exercise have on LDL/HDL?
High [LDL] linked with CVD and high [HDL] has cardioprotective effect. Better indicator is HDL:LDL ratio. Moderate alcohol consumption elevates [HDL] and regular aerobic exercise decreases [LDL]
Where are high and low frequency sounds detected in the cochlea and what range is hearing most sensitive over?
High frequency detected at base and low frequency detected at apex Most sensitive over 2-4kHz
How is interstitial fluid formed?
High hydrostatic pressure and low osmotic pressure at arteriole end forces out fluid to form interstitial fluid and high osmotic pressure at venule end draws back fluid but not all reabsorbed
What causes high median and low median nerve injuries, what signs do each of them present with and how is carpal tunnel syndrome surgically treated?
High median nerve injury caused by supracondylar fractures (causes hand of Benediction). Low median nerve injiry caused by carpal tunnel syndrome as carpal tunnel size decreases so median nerve compressed so progressive loss of co-ordination and strength in thumb with wasting of thenar muscles. Carpal tunnel syndrome treated by cutting flexor retinaculum to relieve pressure
What are the classes of hypertension and what should be done in each patient group?
High normal - <139/89mmHg (consider drug treatment in very high risk patients). Grade 1 HT - 140-159/90-99mmHg (immediate drug treatment in high risk, drug intervention after 3-6 months of lifestyle intervention). Grade 2 HT - 160-179/100-109mmHg (immediate drug treatment, aim for BP control within 3 months). Grade 3 HT - >180/110 (immediate drug treatment, aim for BP control within 3 months)
What is the structure of discontinuous capillaries and what do they allow transport of?
High permeability as they have large openings and discontinuous basal lamina. Allows transport of RBCs, WBCs and various serum proteins
What muscles are used when changing to a single support?
Hip abductors prevent pelvis dropping to unsupported side. Hip adductors used to move body weight
What happens in response to a cut?
Histamine release, dendritic cells take and present antigens to lymph node T cells which proliferate. Memory lymphocytes move to tissues to provide faster 2y immune response
What is the function of extensor/flexor retinacula in the ankle and what passes under them?
Hold tendons in place as they enter foot Extensor retinaculum - deep peroneal nerve and anterior tibial artery Flexor retinaculum (tarsal tunnel) - tibial nerve and posterior tibial artery
What are the paranasal sinuses?
Hollow cavities in frontal, maxillary, sphenoid and ethmoid bones that are lined with mucous membrane and drain into nose
How is the humerus and forearm positioned in females and males and why?
Humerus and forearm are positioned differently in males and females. Men - average 6.7 degrees and women - average 13.6 degrees as it allows the forearms to clear the wider hips
How does structure of lipids influence shape?
Hydrophilic head of glycerol, phosphate and choline. Cylindrical shape causes them to form bilayers rather than micelles so liposome formation favoured
What factors determine movement across a capillary wall and what are the values for these at the arteriolar/venous ends or between the capillary/ISF?
Hydrostatic and oncotic pressures. Hydrostatic pressure is 35mmHg at arterial end and 17mmHg at venous end and 0mmHg in ISF. Oncotic pressure is 26mmHg in plasma and 1mmHg in ISF
How can hyper/hypomethylation cause cancer?
Hypermethylation of CpG islands upstream of promotor prevents tumour suppressor transcription. Hypomethylation of repeat sequences causes genomic instability
How do O2 levels impact CO2 sensitivity?
Hypoxia increases sensitivity of central chemoreceptors to CO2. However, if normal pCO2 then there is very little response to pO2 until quite severe hypoxia (<60mmHg)
Where are hypoxia sensors, how do they respond to O2 levels and what does sympathetic stimulation do to them?
Hypoxia sensors in carotid (at bifurcation of common carotid artery) and aortic bodies. Afferent nerves respond to reduced PaO2 and travel in glossopharyngeal nerve to brainstem. Sympathetic stimulation increases sensitivity to hypoxia
What are the branches of the internal and external carotid arteries?
ICA has no branches outside skull ECA branches into superior thyroid artery, lingual, facial, superficial temporal and maxillary arteries
What proportions of body fluid are intra and extracellular, what are the major ECF/ICF cations/anions and what are the major solutes that contribute to osmolality?
ICF - 60%, ECF - 20% (60% is ISF, rest is plasma). Major ECF cation is Na and major anion is Cl whilst major ICF cation is K and major anion is PO4. Major solutes that contribute to osmolality are Na, Cl, glucose and urea
What are the branches of the IMA?
IMA gives off left colic artery, sigmoidal artery and superior rectal artery
What is infant respiratory ristress dyndrome?
IRDS occurs when premature baby incapable of making enough surfactant so high surface tension in lungs can cause collapse
What 2 methods initiates translation?
IRES in viruses (internal ribosome entry sites) or initiation factors binding to 5' cap which allows binding of small subunit to mRNA
How does IVD thickness change down the vertebral column, what IVD changes do cervical/lumbar lordosis and thoracic kyphosis cause and where do herniated discs occur?
IVDs become thicker down column Cervical/lumbar lordosis - cause wedge-shaped discs wider anteriorly Thoracic kyphosis - uniform-shaped IVDs Herniated discs occur mostly between L4-L5 or L5-S1 as large wedges
What can CXRs be used for?
Identifying lung or bowel pathology, foreign objects and confirming placement of lines and tubes
What is 3' to 5' editing?
If incorrect nucleotide added it is removed and correctly paired 3' end allows addition of next nucleotide
What is a thrifty phenotype?
If nutrient-poor mother during pregnancy, baby has survival advantage with nutrient-poor diet but metabolic disorders with nutrient-rich diet
Describe the missing-self hypothesis
If self signals, inhibition of NK killing even if viral peptides in MHC-I or stress ligands. No self MHC-I and stress ligands and non-self MHC-I cause activating signals to kill infected cell
What is the caloric stimulation test?
If warm water is irrigated into external auditory canal it forms convection currents in semi-circular canal which mimics head movement COWS - Cold water = fast phase nystagmus to Other ear, Warm water = fast phase nystagmus to Same ear
Where does the ileum lead into, where is the appendix found and what are the anatomical features of the colon?
Ileum leads into caecum (attached to appendix). Appendix mostly found retro-caecally and located 1/3 of distance from right ASIS to umbilicus (McBurney's point). Colon has relaxed portions (haustra), semilunar folds on inside and tenia coli that form 3 bands of longitudinal muscle with omental appendices (fatty tags on tenia coli)
What is the iliotibial tract and what does it do?
Iliotibial tract is long aponeurosis for tensor fasciae lata and anterior gluteus maximus and stabilises lateral thigh and knee joint
Where is the iliotibial tract and what is the pes anserinus?
Iliotibial tract runs down lateral aspect of knee joint. Pes anserinus is common insertion for sartorius, gracilis and semitendinosus on medial tibia
Why is cholesterol important, how does LDL uptake occur, how do cells synthesise cholesterol, what does SREBP transcription factor regulate and how does high [cholesterol] affect uptake/synthesis?
Important for cell membrame synthesis and as a precursor to bile salts and steroid hormones. LDL uptake occurs using LDL receptors. Acetyl CoA --> HMG CoA --(HMG CoA reductase)--> cholesterol SREBP regulates HMG CoA reductase activity and LDL receptor levels and high [cholesterol] inhibits HMG CoA reductase and LDL receptor synthesis"
What happens in absence of glucose to provide energy?
In absence of glucose, lipids and proteins broken down into acetyl CoA which then produces ketone bodies (acetoacetate and hydroxybutyrate). Ketone bodies converted back to acetyl CoA in the brain
Where is the RF found and what is it made from?
In central core of brainstem and made from scattered clusters of neurons
What happens during normal paracetamol metabolism and in a paracetamol overdose and what is used to treat OD?
In healthy individual paracetamol converted to non-toxic products. However, if large does then metabolism dependent on CYP450 and converts to NAPQI (toxic). NAPQI normally converted to cysteine and mercapturic acid conjugates using glutathione. If OD then no glutathione left so NAPQI accumulates. IV acetylcysteine used to treat overdose as it replenishes glutathione stores
What causes coeliac disease?
In people with HLA-DQ2 or HLA-DQ8, gliadin peptides broken down by tissue transglutaminase and presented to T cells, causing immune response
What is the function of water in the gut and the body?
In the gut it has a role in hydrolysis reactions, propulsion of food, production of mucus and lubrication. In the body it moves nutrients, hormones, antibodies and O2 in the blood, proteins and enzymes work more efficiently in lower viscosity solutions and also acts as a solvent
What are the exceptions of the H-W equation?
Inbreeding (two alleles independent in gene pool), no heterozygote advantage (not compensated for by increased heterozygote fitness), founder effect (uneven ethnic distribution of recessive disorders)
How can glaucoma be treated surgically?
Incision made in sclera at cornea-sclera junction to allow aqueous humour to drain onto surface of eye and reduce pressure
What is Cheyne-Stokes breathing and in what patient groups is it seen?
Increase in depth and rate of breathing followed by temporary period of apnoea due to damage of sensory input from lungs to medulla. Seen in HF patients, strokes that affect medulla, hyponatremia, TBI, tumours of brainstem, toxic metabolic encephalopathy, often after morphine administration and a symptom of CO poisoning,
What happens in increased CSF [CO2]?
Increased CSF [CO2] --> decreased CSF pH --> drives increased ventilation --> more CO2 expelled from blood --> less CO2 in CSF --> reduces CSF acidity
How does [glucose] impact [malonyl CoA] and what does malonyl CoA affect?
Increased [glucose] causes increased [malonyl CoA]. A high [malonyl CoA] inbhibits CPT-I so inhibits b-oxidation of fats as glucose is plentiful
What causes increased destruction and reduced production of RBCs and what is an indicator for this?
Increased destruction (high reticulocyte) - haemorrhage, haemolysis. Reduced production (low reticulocyte) - haematinic deficiency, chronic disease, medications, infiltration, aplasia
Describe the process that causes smooth muscle contraction
Increased intracellular Ca --> Ca binds to CaM --> CaM activates MLCK --> MLCK phosphorylates myosin light chain using ATP --> increases ATPase activity --> allows myosin head groups to bind actin and undergo cross-bridge cycling
Why does amount of stretch impact ventricular contractility?
Increased overlap between actin and myosin causes an increase in force of contraction
What is respiratory alkalosis and what are the causes?
Increased pH from blowing off too much CO2. Caused by hyperventilation (anxiety, stress or pain, ventilator overventilation), elevated body temp, hypoxemia or CNS trauma
What is metabolic alkalosis and what are the causes?
Increased pH from increased [HCO3], loss of acid (vomiting or gastric suction) or K+ (steroids or diuretics)
How do ADH, aldosterone and ANP affect body fluid balance?
Increased plasma osmolality (sensed by osmoreceptors) and decreased plasma volume (sensed by baroreceptors) triggers AHD release from posterior pituitary which increases number of aquaporins in collecting duct and DCT Aldosterone released from adrenal cortex when reduced [Na] or increased [K] and acts on epithelial ENaC and Na/K ATPase ANP released from cardiac atria when increased blood volume and triggers RAAS, decreased ADH release and decreased aldosterone release
Describe the mechanism of thirst stimulation
Increased plasma osmolality stimulates osmoreceptors in hypothalamus --> triggers thirst centre in anterior hypothalamus Decreased plasma volume --> decreased blood volume --> stimulates RAAS --> stimulates thirst centre
How do volume receptors stimulate a response?
Increased preload causing stretching of atria which causes release of ANP which acts to decrease Na reabsorption which decreases blood water content and blood volume. Ventricles can also release BNP (very little when healthy but raised in HF). ANP and BNP have opposite effect of aldosterone
What are the pulmonary arterial changes that occur during exercise to maintain pulmonary arterial pressure?
Increased ventilation causes alveolar vascular relaxation so reduces total pulmonary vascular resistance. Pulmonary artery distension generates reflex relaxation of smooth muscle to reduce vascular resistance. Arterio-venous shunts can open to allow blood directly into pulmonary veins
What does the sympathetic system do?
Increases HR and contractility, decreases blood to skin and GI, increases blood to skeletal muscle, increased adrenaline and norad, bronchodilation and glycogenolysis in skeletal muscle, mydriasis
What effects does adrenaline release have?
Increases HR and inotropy, bronchodilation, stimulates glucose release from liver and uptake into active muscles, lipolysis
What are the metabolic effects of alcohol consumption?
Increases [acetyl CoA] which inhibits glycolysis and drives to FA synthesis or ketone body production. Also increases [NADH] which inhibits TCA at malate dehydrogenase, also inhibits lactate and pyruvate dehydrogenase
What reduces and increases lung compliance and how does emphysema affect this?
Increases compliance - emphysema and age. Reduces compliance - pneumothorax, pulmonary fibrosis and increased pulmonary venous pressure. Emphysema increases compliance as destruction of lung tissue impairs elastic recoil so lung is more easily distended
How does pancreatic peptide YY (PYY) control feeding behaviour?
Increases ileal absorption, slows gastric emptying and delays gallbladder/pancreatic secretion to inhibit feeding
What are the interspinous ligament and ligamentum flavum?
Interspinous - thin, weak membrane between adjacent spinous processes Ligamentum flavum - highly elastic and extends from lamina to lamina to resist separation and stop abrupt flexion
How is depression treated and what are side effects of treatment?
Increasing monoaminergic transmission by inhibiting reuptake (either SSRI or TCA) TCAs also have affinity for histamine H1, MACHRs and a1/a2 adrenoreceptors Side effects - dry mouth, blurred vision, constipation, urinary retention, fatigue, sedation, weight gain, postural hypotension, dizziness, loss of libido TCAs also have affinity for histamine H1, MACHRs and a1/a2 adrenoreceptors
What is indirect and direct radiation?
Indirect - free radicals break DNA backbone. Direct - alpha, beta or XRs produce ions that break backbone, connections between base pairs or alter base
What is herd immunity?
Indirect protection from infection of susceptible members of population by presence of immune individuals
How are muscle fibres grouped?
Individual fibres in endomysium, groups in fascicles surrounded with perimysium and whole muscle surrounded with epimysium (continuous with tendon)
How are nerves organised by connective tissue?
Individual nerve fibres packaged in endoneurium. Fascicles (groups of functionally related nerve fibres) grouped in perineurium and bundles of fascicles group in epineurium to form whole peripheral nerve
What chest leads give inferior, lateral, anterior and septal views?
Inferior - II, III and aVF. Lateral - I, aVL, V5 and V6. Anterior - V3 and V4. Septal - V1 and V2
What can cause inherited metabolic disorders, how are they caused and what do they lead to?
Inherited metabolic disorders caused by gene defects that result in a change activity of a specific protein. Caused by reduced synthesis, incorrect transport or altered AA composition or 2y causes (defects in cofactor). Can lead to production of a toxic metabolite
How do glycopeptides work and examples?
Inhibit cell wall synthesis by stopping H bond formation. Vancomycin
What are the sub-divisions of the swing phase?
Initial swing - foot pushed off ground and limb accelerates forward Mid-swing - limb moves beneath body until tibia vertical, foot dorsiflexed to prevent toes dragging Terminal swing - limb decelerates and prepares for contact
What are proenzymes and what is chymotrypsinogen?
Initially inactive and can only be activated once. Chymotrypsinogen synthesised in pancreas and activated in duodenum through 2x cleavage and cleaves peptide bonds in aromatic AAs
What are the stages of transcription?
Initiation - polymerase binds to gene, elongation - polymerase transcribes gene, termination - polymerase stops transcribing, processing - mature mRNA formed, export - mRNA leaves nucleus for translation
What are the properties of the inner parts of the IVD and how do they receive nutrition?
Inner annulus fibrosus and nucleus pulposus are aneural/avascular so receive nutrition via diffusion Larger discs have worse diffusion
What does CN X innervate and what are the recurrent laryngeal and phrenic nerves?
Innervates oesophagus, heart and bronchi. Recurrent laryngeal splits from vagus to innervate larynx (right loops under r subclavian but left loops under aortic arch). Phrenic nerve (C3,4 and 5) is motor to diaphragm but sensory to pericardium and pleura
What is ET intubation, what are its advantages, when is it used and what is emergency cricothryoidotomy?
Insertion of plastic tube via mouth, past vocal cords into trachea to control airway and manipulate ventilation and oxygenation. Used in critically unwell, anesthetised patients or those with impending airway obstruction. Emergency cricothyroidotomy where a hole made in cricothyroid membrane
What are the hormones released to control blood glucose, where are they released from and what do they do?
Insulin and glucagon released from pancreas. Insulin (high blood glucose) increases uptake, storage and utilisation. Glucagon (low blood glucose) decreases uptake and utilisation and causes release from storage.
How do insulin-responsive cells respond to insulin?
Insulin binds to insulin receptor --> TKR autophosphorylates --> phosphorylates/activates IRS --> PI3K (lipid kinase) binds to active IRS and phosphorylates lipid --> Akt (protein kinase) binds to lipid and is activated, causing GLUT4 to insert into membrane for glucose uptake
What is the function of insulin in terms of enzymes?
Insulin dephosphorylates enzymes by activating phosphatase enzymes. It turns off glycogen phosphorylase and activates glycogen synthase via protein phosphatase 1-G
What is the structure of insulin, what happens when [insulin] increases, what is the storage form and what is the active form?
Insulin has 2 polypeptide chains linked by disulphide bridge. When [insulin] increases monomers form dimers. At specific pH with Zn dimers form hexamers. When hexamers are secreted it dissociates into active monomeric form
How do insulin, glucagon, adrenaline and calcium affect glycogen metabolism?
Insulin increases glucose storage (liver and muscle) in glycogen. Glucagon causes release into blood from liver by glycogen breakdown. Adrenaline and Ca stimulate glycogen breakdown by controlling glycogen synthase phosphorylation state (active when dephosphorylated)
What can insulin resistance cause?
Insulin resistance can cause hyperglycaemia, inappropriate gluconeogenesis, impaired glycogen synthesis and impaired suppression of lipolysis in adipocytes
What are the different types of mutation and which cause loss of function?
Intergenic (no effect), in UTRs (little effect), regulatory mutations in promotor region, splice site, silent, missense and nonsense, frameshift/non-frameshift from insertion/deletion.
How do the intestines develop and what is omphalocele?
Intestines start to develop a loop that projects outwards. As they form the loop, they rotate and migrate back into abdominal cavity. Omphalocele due to failure of central fusion at umbilical ring causing incomplete closure of abdominal wall and persistent midgut herniation
What are the relative concentrations of K+, protein, Na+ and Cl-?
Intracellular - high K+ and protein, low Na+ and Cl-. Extracellular - low K+ and protein, high Na+ and Cl-
What is Ca2+ and what is its role?
Intracellular messenger and enters cytosol when cell activated. Deactivated by pumping back into ER
What are intracellular receptors?
Intracellular receptors bind directly to DNA regulated by ligand.
What causes apoptosis?
Intrinsic (cell old and mitochondria targeted) and extrinsic (TNF binds to death receptor and activates caspases) triggers. Initiator caspases are 2,8 and 9 and executioner caspases are 3,6 and 7
What can restruct brain drug uptake?
Intrinsic or acquired overexpression of multidrug transporters (eg. ABC (ATP-binding cassette) transporters) at BBB
What is a reflex, how are they stored and how can they be modulated?
Involuntary motor actions triggered by a sensory input. Stored in dorsal and ventral horns in forms of patterns of synaptic connections between inputs, outputs and interneurons
What is the function of iron, where and how is it absorbed and stored, what is the role of haem chelaters and what can iron deficiency/excess cause?
Iron used in haemoglobin to transport O2 in blood ro myoglobin in muscles. Absorbed in duodenum and transported in serum using transferrin to be stored as ferritin in bone marrow and liver. Haem chelators used to prevent oxidative damage and iron overload. Iron deficiency can cause microcytic anaemia but excess can cause haemochromatosis
Describe the sternoclavicular joint
Is a synovial joint (saddle) with a strong surrounding fibrous capsule that connects the upper limb to the axial skeleton. Has a large range of movement and ligaments surrounding SC joint are very strong so lots of force needed to cause an injury
What are the types of skeletal muscle contraction and which cause most damage to muscle?
Isotonic - either concentric or eccentric Concentric - produces tension to shorten Eccentric (most damaging) - produces tension and lengthens Isometric - muscle stays same length and stops flex/ext
What are secondary issues of pharmacological treatment?
Issues related to therapeutic regime (eg. drugs reaching target, adverse effects and drug-resistance)
What are the JG apparatus and macula densa and what do JG cells contain?
JG apparatus at junction of DCT and afferent arteriole and cells contain renin. Macula densa (Na sensors) lines walls of DCT
What are the differences between the jejunum and ileum?
Jejunum - longer vasa recta, fewer arcades, more vascular, less fat in mesentery, larger lumen, more plicae circulares Ileum - shorter vasa recta, more arcades, less vascular more fat in mesentery, smaller lumen and fewer plicae circulares but Peyer's patches
What is the position of the jejunum and ileum and what are the differences between the two?
Jejunum mainly found in upper right quadrant and ileum mainly found in lower left quadrant. Jejunum is more vascularised and has more plicae circulares whilst ileum is less vascularised and has fewer plicae circulares but has Peyer's patches
What are the sections of the abdomen?
L/R hypochondria, epigastric, L/R lumbar, umbilical, L/R iliac and suprapubic
How are LDLs uptaken by cells and what causes familial hypercholesterolaemia/FH?
LDL binds to LDLR and clathrin recruited (causes bulging of membrane to form endosome). H+ pumped into endosome so causes conformational change and LDL separated so cholesterol harvested. Clathrin interaction domain deleted in FH
Where do LMNs and UMNs have their cell bodies, where do UMNs project and what do UMN and LMN lesions cause?
LMNs (a motor neurons) have cell body in ventral horn of spinal cord, UMNs have cell bodies in brain and project down to LMN via descending tracts UMN lesion causes hyperreflexia and LMN lesion causes flaccid paralysis
What type of bone is found in a normal skeleton and what bone type is found in immature, healing and pathological bone?
Lamellar bone found in normal skeleton and has cortical (forms strong outer shell) and trabecular/cancellous (mesh that gives a bit of flexibility) layers. Woven bone found in immature, healing or pathological bone and has a random structure so much softer
What is the cavernous sinus and what artery passes through?
Large collection of thin-walled veins. ICA passes through and makes acute bend so can be seen twice
What are macromolecules?
Large molecules (eg. collagen, elastin, glycoproteins and proteoglycans)
What are colloids?
Large molecules that can't cross membrane and found in intravascular area so pulls fluid back into capillaries
What are dorsal columns, what fibres do they contain, what side do these fibres run in the dorsal columns and what sensations do they transmit?
Large tracts of white matter in dorsal spinal cord (fasciculus cuneatus for upper limb and fasciculus gracilis for lower limb). Contains pre-synaptic branches of 1y afferents in peripheral nerve that run via ipsilateral tract and transmit vibration, proprioception and discriminative touch
What are the features of lumbar vertebrae?
Large vertebral body and sturdy laminae L5 largest moveable vertebra as it carries weight of upper body
What is the structure of monocytes and when are they increased?
Large with kidney shaped nucleus. Increased in chronic infection and viral infection
How is the structure of pulmonary arteries different to that of systemic arteries?
Larger lumen diameter, thinner and walls with less smooth muscle. Highly distensible and compressible with high compliance that allows stretch during systole to smooth the blood flow
How long can stored ATP last for muscle metabolism and how can more be made?
Lasts 2-3secs More made by aerobic/anaerobic respiration or by using phosphocreatine
What is the medial to lateral organisation of the RF?
Lateral - sensory (afferent input) Medial - motor (efferent output) Midline - modulatory (eg. pain filtering) Sensory part gives input to motor portion
What does PICA stroke cause?
Lateral medullary syndrome, vertigo, nystagmus, nausea/vomiting, dysphonia, contralateral loss of pain and temp in body, loss of pain and temp in ipsilateral face and loss of gag reflex with ipsilateral Horner syndrome
What movements do the extra-ocular muscles cause?
Lateral rectus abducts and medial rectus adducts Superior rectus - elevate, adduction and intorsion Inferior rectus - depress, adduction and extorsion Superior oblique - depress, abduct and intorsion Inferior oblique - elevate, abduct and extorsion
What are the main muscles for lateral and medial rotation of the hip?
Lateral rotators - gluteus maximus Medial rotators - gluteus medius/minimus and tensor fasciae lata
What do the lateral sulcus and longitudinal fissure separate?
Lateral sulcus separates frontal and parietal lobes from temporal lobe and longitudinal fissure separates two hemispheres
What is the passage of CSF flow?
Lateral ventricles --(interventricular foramen (of Monro))--> 3rd ventricle --(cerebral aqueduct)--> 4th ventricle
What muscles makes up the lateral and anterior abdominal wall?
Lateral wall made from external and internal oblique muscles and transversus abdominis. Anterior wall made from rectus abdominis
What are the meninges?
Layers than cover the brain. Dura mater (inner and outer layers and form superior sagittal sinus that holds CSF), arachnoid, subarachnoid space (holds CSF) and pia mater
What are the limb leads and what do they show and in what direction?
Leads I (r axillia to L axilla) , II (r axilla to L leg) and III (L axilla to r leg) and give frontal plane electrical activity
Describe the path of sympathetic preganglionic axons
Leave through ventral route between T1 and L2. Travel via spinal nerves to sympathetic chain via white rami. Some synapse in paravertebral ganglia, some pass through to prevertebral ganglia and others pass through both to synapse in adrenal medulla
What is the function of the left and right prefrontal lobes?
Left - focus of attention and blocking out distracting inputs to facilitate analytical and logical skills Right - maintains broad overall vigilance on all sensory inputs
Describe the branches of the coeliac trunk
Left gastric artery - gives off oesophageal branches and anastomoses with right gastric artery to supply lesser curvature Splenic artery - gives off short gastric arteries and left gastroepiploic arteries Common hepatic artery - gives off right gastric artery and gastroduodenal artery (gives off superior pancreaticoduodenal artery and right gastroepiploic artery) then hepatic artery proper splits into left and right hepatic arteries (right gives off cystic artery)
What are the left and right heart and the pressure in each circuit?
Left heart is systemic and right heart is pulmonary circulation. Pressure is lower in pulmonary circuit as lower pulmonary vascular resistance and blood not being distributed to different organs
What is the appearance of extradural haematoma on CT?
Lens-shaped where dura pulled away from skull
What are the effects of different laryngeal nerve palsies?
Lesions to recurrent laryngeal nerve cause hoarseness, aphonia and stridor. Lesions to superior laryngeal nerve cause weak voice, low pitch, reduced range and easily tiring voice
How are leucine, isoleucine and valine metabolised and what do each of them form?
Leucine/isoleucine/valine --(transamination)--> correspoinding a-keto acid --(oxidative decarboxylation)--> corresponding acyl CoA thioesters --(a,b-dehydrogenation)--> corresponding a,b unsaturated acyl CoA thioesters Isoleucine --> propionyl CoA and acetyl CoA Leucine --> acetoacetate and acetyl CoA Valine --> succinyl CoA
What is connective tissue?
Lies between two other tissues and consists of cells and ECM. Loose connective tissue (adipose, blood and serous membranes), dense connective tissue (dermis), bone and cartilage
What are the ligaments in the foot?
Ligaments around tarsals give stability Spring (plantar calcaneonavicular) - continuous with medial ligament Long and short plantar ligaments on lateral side
What type of receptor are NACHRs and what does activation cause?
Ligand-gated ion channel needing 2x ACH to bind to activate Activation allows Na influx and depolarisation (end plate potential)
What are the different types of microscopy?
Light microscopy - 2000x, electron microscopy - 500,000x. Light used for immmunohistochemistry and immunocytochemistry
How does light pass the eye and what is the function of the vitreous humour?
Light passes through aqueous humour in anterior chamber then through pupil, lens and into posterior chamber filled with vitreous humour (holds shape of eye fixed and rigid to maintain focussing accuracy
How does rate change with [E] and [S]
Linear increase with [E] at constant [S], exponential then asymptotes with increase in [S] and constant [E]. Maximum activity when active sites saturated
How is lipogenesis controlled?
Lipogenesis is controlled by regulation of acetyl CoA carboxylase. Controlled by phosphorylation (phosphorylated/inactivated by glucagon), polymerisation (promoted by citrate and inhibited by palmitoyl CoA) where polymer is the active form. Also under longer-term genetic control
When does lipogenesis occur, where are FAs made in the cell and in the body and what is the process of lipogenesis?
Lipogenesis occurs when excess of glucose. FAs are made in the cytoplasm in the liver, white adipose tissue and lactating mammary glands. Acetyl CoA combines with oxaloacetate to form citrate --> citrate transported into cytosol where it is broken down to oxaloacetate and acetyl CoA --> acetyl CoA carboxylase converts acetyl CoA into malonyl CoA --> malonyl CoA used to extend FA chain by 2C as CO2 is lost
What does lipolysis release and what can each of the products be used for?
Lipolysis of TAGs releases glycerol (used for gluconeogenesis) and FAs (can be oxidised for energy or converted to ketone bodies in non-oxidative tissues)
What is the function of lipoprotein, what is their membrane structure, what are found in the core, what is found on the outer layer, what are the different types of apoproteins and what are the functions of apoproteins?
Lipoproteins provide a means to transport TAGs, cholesterol and phospholipids and some vitamins (A and E). Have a phospholipid monolayer with cholesterol esters and TAGs in the core. Outer layer contains apoproteins, cholesterol and phospholipids. Apoproteins can be embedded (apoB) or loosely bound (apoC). Apoproteins control the fate of lipoproteins by interacting with receptors and activating/inhibiting enzymes
What is the function of the lips, teeth, salivary glands, tongue, soft palate and tonsils?
Lips - control entry and exit to mouth Teeth - mechanically break down food Salivary glands - chemically digest food Tongue - moves food to the back of the mouth Soft palate - elevates to prevent food passing into nasal cavity Tonsils - immunological defence
What are types of bacteria vaccines?
Live attenuated (BCG, typhoid and cholera) and inactivated (from chemical treatment, heat or purification). Produce lots of antigens without risk of infection
What are the types of viral vaccines?
Live attenuated, inactivated vaccines, recombinant bacterial vectors, recombinant viral vectors, virus-like particles, DNA and synthetic peptides
How is action potential spread in unmyelinated neurons and how is backward spread prevented?
Local spread of charge on inside membrane opens further Na+ VGCs. Backward spread prevented as Na+ VGCs are in absolute refractory period
What can staphylococcus and enterotoxins/exotoxins cause?
Localised (respiratory, musculoskeletal) or systemic infection (bacteraemia, sepsis and endocarditis). Cause carbuncles (boils) and impetigo (skin infection causing blisters). Enterotoxins cause acute staphylococcal enterocolitis and toxic shock syndrome from superantigens. Exotoxins cause scalded skin syndrome
What are the lock-and-key and induced-fit models?
Lock and key - substrate fits exactly to rigid active site which only matching shape can fit. Induced fit - active site flexible and closes around substrate so can have multiple substrates
How does the RF modulate via noradrenaline?
Locus coeruleus activated by hypothalamus activates SNS Reticulospinal tract activates preganglionic sympathetics and also activates motor system so reflexes faster. Inhibits pain and ascending fibres activate central sympathetics to cause alertness
What are the types of lipid anchors?
Long chain fatty acids and cholesterol intermediate. Myristoyl anchor from amide link between terminal amino group and myristic acid, palmitoyl anchor from thioester link between cysteine and palmitic group, farnesyl anchor from thioester link between cysteine and prenyl group
How do loop diuretics, thiazide diuretics and aldosterone antagonists work (and side effects for loop diuretics)?
Loop diuretics inhibit NKCC2 in ascending limb so prevent Na reabsorption (NKCC2 also found in cochlea so prolonged use can cause permanent hearing loss). Thiazide diuretics inhibit Na-Cl cotransporter in DCT and aldosterone antagonists (spironolactone) inhibit Na/K exchange in collecting ducts so are K sparing
What causes Parkinson's disease?
Loss of cells in substantia nigra of midbrain which produces dopamine so insufficient dopamine at level of receptor
How can stretch receptors have reduced sensitivity and what can cause this?
Loss of elastin in sinus walls means less able to stretch so higher pressure needed to stimulate stretch receptors. Free radicals from cigarette smoke can damage endothelium and elastic lamina
What mutations are common in tumour suppressors?
Loss-of-function mutations such as point mutations, small deletions or truncations
What increases brain blood flow and what are the properties of cerebral arteries and veins?
Low [O2] or high [CO2] increase flow Arteries - thin walled, easily blocked/distorted/ruptured Veins - thin walled, no valves, no muscle or elasticity to help return
What is hyponatremia, causes and outcome?
Low plasma Na+. From liver or kidney failure, congestive heart failure or overhydration. Can cause cell swelling and lysis. Symptoms - convulsions, coma and death
What are partial agonists?
Lower efficacy than full agonists so produce partial response. Have lower affinity for receptor than full agonist and occupy the receptor, preventing binding of other agonists
What are lucent lesions, sclerotic lesions, periosteal reactions, soft tissue calcifications, osteopenia, osteonecrosis, fractures, orthopaedic hardware and joint integrity on an XR?
Lucent lesions - darker areas Sclerotic lesions - whiter areas Periosteal reactions - loss of smooth appearance of bone edges Soft tissue calcifications - white patches in soft tissue Osteopenia - localised reduciton in bone density Osteonecrosis - death of bone with loss of shape Fractures - discontinuity of bone (black line separating pieces) Orthopaedic hardware - metal or plastic Joint integrity - joint space/orientation
What are the main spinal roots of the lumbar and sacral plexi and what are the main lumbar nerves?
Lumbar plexus - L1-L4 and sacral plexus - S1-S4 Main lumbar nerves are femoral and obturator nerves (L2-L4)
What is the function of the lumbricals, dorsal interossei and palmar interossei?
Lumbricals flex MCP and extend IP joints. Dorsal interossei abduct fingers (DAB) and palmar interossei adduct fingers (PAD)
Describe the luminal, mucosal and post-absorptive phases of digestion
Luminal phase - ingested food is broken down by acid in stomach and alkali in small intestine, substrate-specific enzymes from gastric and small bowel mucosa and pancreas. Mucosal phase - pre-digested nutrients selectively taken up at brush border membrane of enterocytes. Post-absorptive phase - transport of absorbed nutrients via lymphatics and portal circulation
Where is the lung apex, inferior border of the lungs and cardiac notch and what is potential space on inferior pleural sac called?
Lung apex - 2cm above clavicle, inferior border - 6th rib, cardiac notch - 4th rib. Potential space called costophrenic recess
What does the elasticity of the lung and chest walls do, what holds them together and what does the tension at the end of expiration do?
Lung elasticity has tendency to collapse but chest wall elasticity has tendency to expand. Held together by intrapleural fluid that creates cohesive force so as chest wall expands lung is obligated to follow. Tension due to opposing forces at end of expiration creates intrapleural pressure (slightly negative)
Where is lung sensory nerve supply to, where is sympathetic supply from and what does sympathetic activation do?
Lung sensory nerve supply to T2-T6. Sympathetic supply from T2 and T4-T6 that passes into lungs in plexi around pulmonary arteries. Sympathetic activation causes bronchodilation via b2 receptors
What are platelet precursor cells called and platelet lifespan?
Megakaryocytes. Platelets have lifespan of 10 days
Where do MCA and ACA travel and what does each supply?
MCA travels out to lateral wall and gives off lenticulostriate arteries. ACA supplies medial wall and passes forward and then loops back
What WBCs are found in alveoli and the what are the types of pneumocytes in epithelium?
Macrophages and lymphocytes. Type I (squamous, 90%) and type II (cuboidal, 10%)
Describe the structure of the mandible
Made anteriorly from body. Lateral side has head/neck and coronoid process that join to form ramus. Angle where ramus joins body. Mandibular foramen on medial ramus and mental foramen on anterior part of body
What makes up the BBB?
Made by astrocyte end-feet and tight junctions between endothelial cells lining cerebral capillaries (prevent proteins leaving blood)
What is collagen and what are the different types?
Made from a repeating sequence where 3rd AA glycine and X-Y-Gly (proline or hydroxyproline) with triple helix structure. Type I - bone, cartilage, skin, dentin, tendons and is densely packed. Type II - cartilaginous tissue and more loose. Type III (reticular) in highly cellular organs and ligaments, type IV - forms basement membrane
What is the BM?
Made from basal lamina (lamina densa and lamina lucida) and supports epithelial/endothelial cells
What are the main sections of the brain?
Made from cerebrum (frontal, temporal, parietal and occipital lobe with insula between frontal and temporal lobes), cerebellum and brainstem
How is ACH metabolised?
Made from choline and acetyl-CoA in synapse. Broken down by acetylcholinesterase and choline transported back into axon terminal
What joints make up the ankle joint, where does the talus sit and what movements does the talocrural joint allow?
Made from distal tibiofibular and talocrural joints Talus sits on top of calcaneus between fibula and medial malleolus Talocrural joint allows plantar/dorsiflexion"
What muscle makes up the tongue, what is it covered by and where does it receive motor supply from?
Made from extrinsic (control position) and intrinsic (control shape) muscles and is covered by a mucous membrane. Receives motor supply from hypoglossal nerve
How are fatty acyl chains made?
Made from fatty acid synthase (ketosynthase --> ketoreducase --> dehydratase --> enoylreductase 7x that builds up chain 2C at a time. Thioesterase releases palmitate
What bones make up the oral cavity?
Made from mandible inferiorly and maxilla and palatine bones superiorly
What is the structure and function of the myelin sheath and what do demyelinating diseases of PNS do?
Made from multiple layers of lipid membrane with little cytoplasm that electrically insulate the axon and have low electrical capacitance so can't store charge and forces current to flow only at nodes. Demyelinating diseases damage myelin sheath and block AP conduction
What is the 4y structure?
Made from other 3D folded subunits (can be homo - same subunits or hetero - different subunits)
What are proteoglycans and how do they change with age?
Made from peptide chains and -ve charged covalently bound sugars that hold water because of GAG chains. Become less complex with age so causes drying in intervertebral discs
What is the bacterial cell wall?
Made from peptidoglycan and protects against shock or immune system. Gram +ve have thick peptidoglycan, gram -ve have thin peptidoglycan with outer cell membrane and LPS
What are the parts of the lateral ligament?
Made from separate ligaments - anterior talofibular, posterior talofibular and calcaneofibular
What bones make up ankle and why can you invert foot more?
Made from tibia, fibula and talus Can invert more because lateral malleolus extends further inferiorly
Where is ACH made (and from what) and how is it broken down?
Made locally in synaptic bouton from acetyl CoA and choline using choline acetyltransferase Broken down by ACHE and choline recycled and taken back up into axon terminal
Where are the main ANS targets in the airway and what does SNS cause?
Main ANS targets are airway smooth muscle, submucosal glands and blood vessels. SNS causes bronchodilation as adrenaline release into bronchial vessel that acts on b2 adrenoreceptor
What are the four main bone junctions found in the skull?
Main bone junctions are bregma (superior-anterior), lambda (superior-posterior), pterion (lateral-anterior), asterion (lateral-posterior)
What does TCA cycle rate depend on and what stimulates/inhibits dehydrogenase enzymes?
Mainly depends on NAD availability. NAD availability dependent on ETC rate so linked to ATP:ADP ratio. Both NADH and ATP inhibit isocitrate dehydrogenase and a-ketoglutarate dehydrogenase. Stimulated by Ca released in muscle contraction
What is the subintima in the synovial membrane and what is added to synovial membrane ultrafiltrate?
Mainly made from loose connective tissue (collagen type II) and contains dense network of fenestrated capillaries. Also contains fat tissue. Hyaluronic acid added to membrane ultrafiltrate
What are MHCs, to what cells do they present antigens and what are the characteristics of MHC genes?
Major genetic region that determines compatability of tissues. MHC-I presents antigen to CD8+ cells, MHC-II presents antigen to CD4+ cells. Genes are polymorphic (MHC molecules on grafts are foreign so are rejected) and polygenic so there are lots of MHC genes so diversity. Antigen binding promiscuous so is non-specific
What is the major hip flexor, what movements does sartorius do and where do quadriceps insert?
Major hip flexor is iliopsoas (iliacus and psoas major). Sartorius flexes hip and knee and quadriceps insert onto quadriceps tendon (changes to patella ligament over patella)
What are marginal hypertension, definite intervention threshold and pulse pressure?
Marginal hypotension - >140/90mmHg, definite intervention threshold - >160/100mmHg. Pulse pressure = systolic - diastolic
How can AAA surgery cause a spinal cord deficit and how does severe drop in BP affect its blood supply?
May lose sensation and voluntary movement below level of occlusion. Severe BP drop for 3-6mins may reduce or stop blood flow from segmental medullary to anterior spinal
What is myoglobin, what does it act as and how can it cause disease?
Mb is a single subunit with greater O2 affinity than Hb and found in muscles so acts as an oxygen reserve/store. Can cause rhabdomyolysis when released from damaged muscle tissue as it's toxic to renal tubular epithelium when filtered so can cause acute renal failure
What is McArdle's disease, what can intense exercise cause, how is rhabdomyolysis diagnosed, how is exercise managed and how is it diagnosed?
McArdle's disease is a deficiency in muscle glycogen phosphorylase so intense exercise can result in muscle damage (can cause rhabdomyolysis). Rhabdomyolysis diagnosed by creatine kinase and myoglobin (causes dark urine). Exercise managed to get into 2nd wind and diagnosed by ischaemic forearm test, muscle biopsy and sequencing
Why are enlarged ventricles with no increase in ventricular wall thickness bad?
Means that they are overstretched so muscle fibres contract more weakly (meaning greater EDV causes smaller SV and CO)
What are examples of live attenuated vaccines and what are pros/cons?
Measles, influenza are made in tissue culture. Can't be given to immunodeficient patients and risk of virus shedding
What is tonicity and what affects it?
Measure of effective osmotic pressure gradient and determines cell volume. Affected by solutes that can't cross semi-permeable membrane. Hypotonic solution causes cell swelling and lysis, hypertonic solution causes cell shrinkage
How is total lung capacity measured/calculated?
Measured by rebreathing helium (not absorbed into blood) until evenly distributed. Gas is diluted by residual gas volume. TLC = V2 = (C1 x V1) / C2
How is disease spread measured and how can others be protected?
Measured using contact tracing and community monitoring. Others protected by ring vaccination
How is V/Q ratio measured, and what causes mismatch?
Measured using isotope scanning. Increased V/Q from PE as perfusion reduced. Decreased V/Q from pneumonia as ventilation reduced. COPD has regional V/Q mismatch
What are muscle spindles and what do they do?
Mechanoreceptive proprioceptors innervated by y-motor neurons. Muscle stretch causes muscle spindle stretch which stimulates sensory nerves to detect length change
What are irritant receptors, where are they and what do they do?
Mechanoreceptors sensitive to noxious gases, dust, cigarette smoke and cold air and cause coughing. Found between epithelial cells in trachea and large bronchi
What do medial and lateral rotators do to give stability, how do the ligaments in the hip joint provide strength and how do they cover the head/neck of femur?
Medial and lateral rotators give reciprocal pull that provides stability. Ileofemoral and ischiofemoral ligaments strengthen capsule and twist/tighten articular capsule when hip extends. Completely cover head/neck of femur anteriorly but only cover head of femur posteriorly
What are the arches of the foot?
Medial arch and lateral longitudinal arches and transverse arch Medial arch is resilient due to many bony components Lateral arch is flatter as fewer bones and talus transmits body weight through it
What is the mediolateral organisation of the brainstem?
Medial to lateral - somatic motor (CN III, IV, VI and XII), branchial (motor V, CN VII), visceral motor (dorsal motor root of CN X), visceral sensory (NTS) and other sensory (main sensory CN V, vestibulocochlear)
What are the medial-superior, lateral-superior and inferior borders of the popliteal fossa and what structures run through popliteal fossa?
Medial-superior - semimembranosus/semitendinosus Lateral-superior - biceps femoris Inferior - gastrocnemius Popliteal artery and vein run together through popliteal fossa
Where do median nerve, ulnar artery/nerve and radial artery run in forearm?
Median nerve - deep to palmaris longus tendon Ulnar artery/nerve - lateral to FCU Radial artery - lateral to FCR
Where does the median nerve run through the arm and what are the types of injury to this nerve?
Median nerve runs in anterior arm then runs with brachial artery through cubital fossa. Can be damaged in high or low median nerve injuries
What does cingulate cortex mediate, how does pain produce arousal and what does co-activation of anterior and lateral STTs allow?
Mediates distress, unpleasantness and emotional impact of pain. Pain produces arousal via reticular formation. Co-activation allows pain localisation (via anterior STT) and assessment of unpleasantness (via lateral STT)
What other factors contribute to bronchomotor tone?
Mediator release (eg. histamine), NANC systems, rapidly adapting pulmonary receptors (cough receptors), slowly adapting pulmonary receptors and CO2
What are the types of axon resistance and how does this affect leakage?
Membrane and cytoplasmic resistance. Cytoplasmic resistance decreases with increased diameter and membrane resistance decreases with myelin as acts as wall that prevents outward flow of ions, increasing conduction velocity. Leakage affected by which path has least resistance
How thick is the synovial membrane, what cells is it made from, what are the different of these cells and what feature allows fluid movement?
Membrane is 1-3 cells thick and made from synoviocytes. Type I (macrophage-like cells for immune surveillance) and type II (fibroblast-like connective tissue for proteoglycan production). No basement membrane between synoviocytes and subintima so allows fluid movement
What are menisci, what are their roles and describe the structure of the medial and lateral menisci
Menisci are plates of fibrocartilage that deepen the knee joint and help with shock absorption Medial meniscus - C shaped, broader posteriorly than anteriorly, anteriorly attached to ACL and firmly attached to tibial collateral ligament Lateral meniscus - nearly circular, smaller and more freely moveable and attached to PCL
How does intramembranous ossification occur?
Mesenchymal stem cells differentiate into osteoblasts --> osteoblasts secrete bone matrix that calcifies --> turn into osteocytes --> mesenchyme on outside turns into periosteum that holds progenitor cells --> blood supply provides osteoclasts that can remodel woven bone into lamellar bone
What is metabolic flexibility, how is this different between fit and sedentary individuals and what is metabolic inflexibility?
Metabolic flexibility is the ability to switch between glucose and lipids. Fitter people have better metabolic flexibility so a greater range of switching. Metabolic inflexibility is the constrained ability to switch between fasting and insulin stimulation
How can patients die from cancer?
Metastatic burden (1kg+ tumours or 100g in brain), immunosuppression, haemorrhage, organ failure
What are the microcytic, normocytic and macrocytic anaemia and what causes each?
Microcytic (MCV <80fL) from iron defficiency and thalassaemia. Normocytic (80-100fL) - haemorrhage, sickle cell anaemia, chronic disease, renal failure, leukaemia. Macrocytic (>120fL) - folate/B12 deficiency, alcohol or liver disease
What is the appearance of iron deficiency anaemia cells and what are the causes?
Microcytic and hypochromic. Caused by diet (rare), menstraul loss, infection, growth spurt, pregnancy, GI loss (bleeding ulcers, IBD or cancer)
What are cell-surface adaptations?
Microvilli - for nutrient absorption and secretion, cilia (primary for receptors and motile in trachea), flagella - movement
What CNs do the midbrain, pons and medulla give off and what functions do they regulate?
Midbrain - CN II - CN IV for auditory and visual reflexes Pons - CN V - CN VIII for mastication, eye movements, facial expression, taste, blinking, lacrimation, audition, salivation Medulla - CN VIII - CN XII for equilibrium, audition, deglutition, salivation, taste, respiration, circulation, GI function, neck and shoulder movements, tongue movements, coughing, vomiting
What is the function of the midbrain, pons and medulla?
Midbrain - processing auditory and visual data and maintenance of consciousness Pons - relay to cerebellum and subconscious somatic/visceral motor centres Medulla - autonomic centres
What are the anatomical features of the midbrain, pons and medulla?
Midbrain has superior colliculus (visual reflexes), inferior colliculus (auditory relay) and cerebral peduncle (tract descending from cortex into spinal cord) Pons has cerebral peduncles (superior, middle and inferior), 4th ventricle (medially) and basal pons (bridge composed of transverse and descending fibres) Medulla has 4th ventricle, pyramids and olive
What is the internal oblique muscle, what direction do its fibres run, where does it attach and where does it stop?
Middle layer of lateral abdominal wall. Fibres run in anterior-superior direction and attach to ribs and iliac crest. Becomes aponeurotic at midclavicular line
What are electrolytes and examples?
Molecules broken down to cations and anions when in water (eg. K+, Na+, Mg2+, Ca2+) and they can affect volume and distribution of fluid in body
What is surface tension and its effects on the lung?
Molecules on the surface of a liquid have a stronger cohesive force. Water surface on inside of alveoli trying to contract, resulting in alveoli trying to collapse and force out air. Net effect is to generate elastic contractile force throughout entire lung
What are the types of genetic disorders?
Monogenic disorders (mutations in single gene), polygenic disorders (combined effect form many genes - diabetes), chromosomal disorders (change, gain, loss or exchange of chromosome elements) and somatic disorders (disorders of body cells)
What are the types of carbohydrates?
Monosaccharides (glucose, fructose and galactose), disaccharides (maltose, lactose and sucrose), oligosaccharides (between 3-10 monosaccharides - heparin, blood group antigens) and polysaccharides
What is decremental conduction, where is it seen and what is its role?
More frequent stimulation causes slower conduction. Seen at AVN and prevents rapid conduction to ventricles in case of rapid atrial rythyms
What is the most common dislocation in the body, what forced movements cause them and what nerve is susceptible to damage due to this dislocation?
Most common dislocation in a GH joint dislocation (caused by forced abduction, external rotation and extension). Axillary nerve is most susceptible to damage from shoulder dislocation
How can mutations cause cancer?
Mutations in proto-oncogenes to form oncogenes, tumour suppressor genes or sporadic mutations
What makes up most of the livers blood supply, where does oxygenated arterial blood come from, where does mixed blood drain, what are Kuppfer cells and what does the portal triad contain?
Most of the blood supply is from portal circulation. Oxygenated arterial blood comes from coeliac axis and mixes with portal venous blood in sinusoid that drains into central vein. Kuppfer cells are macrophages found in sinusoid that prevent infections. Portal triad contains hepatic arteriole, portal venule and biliary ductule
Where does the majority optic nerve axons project to in brain, what pathway mediates visual perception and what can damage to this cause?
Most project to lateral geniculate nucleus (LGN) on side of thalamus. Lateral geniculate-occipital cortex pathway mediates visual perception so damage to this (eg. by posterior cerebral artery infarct) can cause blindness
Where does most reabsorption occur and how?
Most reabsorption occurs in PCT. Na+ pumped from cell into ISF (Na/K ATPase) which then allows passive diffusion of Na (influx carries glucose) from lumen into cell and into interstitium, drawing water with it
What are most brain tumours and what often causes epilepsy?
Mostly gliomas as neurons don't undergo mitosis Often due to glial cell malfunction in area affected by infarct or neuronal insult (eg. contusion, impact, infection)
Where are most colorectal cancers found, what is the problem with caecum cancers and what are colonic polyps?
Mostly in descending colon. Caecum cancers present quite late as they don't change bowel habits. Colonic polyps are benign growths that can turn cancerous so should be removed
How are most skull bones joined and what are the neurocranium and viscerocranium?
Mostly joined by sutures. Neurocranium/cranial vault protects the brain and viscerocranium/facial skeleton forms framework of the face
What direction are most hip dislocations, how do they present, how can the acetabulum be involved and what nerve can be damaged and why?
Mostly occur posteriorly. Present as medial rotation of hip, knee and ankles with slight flexion and adduction. Acetabulum can be fractured with chips breaking off of posterior rim. Sciatic nerve can be damaged as it runs posteriorly and medially to hip joint
What is the function of CN XI, what are its spinal cord roots and what is its pathway?
Motor innervation to SCM and trapezius with spinal cord roots from C1-C5. Passes up through foramen magnum then back out skull via jugular foramen
What is a motor unit and how do they vary?
Motor unit - LMN, motor axon and set of muscle fibres it innervates Vary in number of muscle fibres innervated by single motor fibre
What is the IgA isotype found in mucosal plasma cells and what is IgA used for?
Mucosal plasma cells contain IgA2 and IgA is used for agglutination to prevent pathogenic bacteria/viruses from binding to epithelial surface
What is multi-unit and single-unit smooth muscle and what are their functions?
Multi-unit cells receive their own synaptic input with little electrical coupling so allows for finer control (in iris and larger blood vessels). Single-unit cells innervated as a sheet and AP propagated by gap junctions so allows contraction as a whole sheet
What are multigenerational and transgenerational influences?
Multigenerational/direct - influences F1/2 from mother and F1 from father. Transgeneration/indirect - influences F3 from mother and F2 from father
What are the microscopic features of skeletal muscle?
Multinucleate with peripheral nuclei. Sarcolemma (plasma membrane), sarcoplasmic reticulum (stores Ca), sarcoplasm (cytoplasm with myoglobin to store O2) and muscle proteins arranged in sarcomeres
What are the causes of muscle fatigue and how does exercise affect the density of mitochondria?
Muscle fatigue caused due to lack of phosphocreatine, build-up of lactate (decreases pH and inhibits glycolysis and oxidative phosphorylation), running out of glycogen or insufficient (aging), inflexible (obesity) or inefficient mitochondria. Exercise increases mitochondria density
What provides dynamic support to the foot?
Muscle tendons that insert into arches to increase height (tibialis anterior) or run through sole and prevent separation (fibularis longus and small intrinsic muscles)
What is muscle tone dependent on and how is tone maintained and adjusted?
Muscle tone dependent on monosynaptic reflex integrity. Tone maintained reflexively and adjusted to needs of posture and movement
What changes occur when changing to a single support?
Muscles around hip of supporting leg become active to move body weight over supporting leg and prevent pelvis drop on unsupported side
What are the rotator cuff muscles?
Muscles that surround the GH joint and provide support. Supraspinatus (abduction), infraspinatus and teres major (lateral rotation), subscapularis on anterior surface for medial rotation Supraspinatus tendon susceptible to tear
What is the pharynx, what parts is it made from and what are the sets of pharyngeal muscles?
Muscular tube connecting oral/nasal cavities to trachea and oesophagus. Made from oropharynx, nasopharynx and laryngopharynx. Muscles are either circular or longitudinal
What is the oesophagus, what are the layers of muscle fibres, what are the types of muscle found in the oesophagus and what innervates it?
Muscular tube that propels food from pharynx to stomach. Has inner circular muscle and outer longitudinal muscle. Upper 1/3 made from skeletal muscle and lower 2/3 made from smooth muscle. Innervated by vagus nerve (CN X)
What is an important feature of effective neuropharmacological treatments?
Must be able to cross BBB so must be lipophilic
What is DNA mismatch repair?
MutS binds to mismatched base pair and MutL scans nearby DNA for nick and triggers strand removal. DNA then synthesised
Where are the myenteric and submucosal plexi found and what do they control?
Myenteric plexus (controls gut motility) found between circular and longitudinal muscle and submucosal plexus (controls secretions) found between circular muscle and submucosa
What is the role of ATP in muscle contraction?
Myosin head binds to tropomyosin and ADP released, causing myosin head rotation. ATP binds, causing cross-bridge detachment and ATP hydrolysis causes reset of myosin position
How do rods respond to darkness?
Na pumped out cell body region (inner segment) and Na also pumped out outer segment to keep cell depolarised and cause tonic release of glutamete
What classes of drugs interact with contractile cell action potentials?
Na+ blockers (weak - lidocaine and phenytoin, moderate - quinidine and procainamide, strong - flecainide, propafenone), CCBs (diltiazem, verapamil), beta blockers (propranolol, metoprolol), K+ blockers (sotalol, amiodarone)
How do secretory cells of the crypt maintain intestinal water content?
Na, K and Cl enter intestinal cell by cotransport from ISF. Cl enters lumen via CFTR and Na reabsorbed into ISF using Na/K ATPase. Negative Cl in lumen attracts Na by paracellular pathway so H2O follows
What is the function of the nasal cavity, what are the divisions and where does the olfactory nerve/CN I run?
Nasal cavity warms/humidifies air, removes and traps inhaled pathogens, for sense of smell and drains paranasal and lacrimal sinuses. Contains vestible (nostrils), respiratory region and olfactory region. Branches of CN I run through cribriform plate of ethmoid bone
Describe the structure of the nasal septum and lateral wall of the nasal cavity and what are the roles of the parts of the lateral wall?
Nasal septum contains septal cartilage anteriorly and vomer (inferior) and perpendicular plate of ethmoid bone posteriorly. Lateral wall contains superior, middle and inferior conchae with meatus between each. Concha create turbulent airflow so air spends more time in nasal cavity
What are the properties of the cornea, how is its shape maintained and how do tears contribute to its function?
Nearly avascular but richly supplied with nerve fibres. Shape maintained by intraocular pressure. Tears provide smooth refractive surface to prevent scattering and improve optical quality
What are the medical treatments for GORD and how do NSAIDs affect it?
Nearly completely mitigated by PPIs (eg. omeprazole). TLOSRs reduced by neurological drugs (baclofen), H2R antagonists, antacids (eg. gaviscon that neutralise acid). Gaviscon contains sodium alginate (forms protective raft) and potassium hydrogen carbonate (neutralises acid). NSAIDs block COX-1 so prevent PGE2 formation from arachidonic acid, decreasing mucus and HCO3 secretion
What occurs in necrosis and apoptosis and how can necrosis be treated?
Necrosis - membrane blebs and breakdown of plasma membrane releases cell organelles and contents, apoptosis - organelles packaged in apoptotic bodies that are digested by phagocytes. Necrosis can be treated with surgical removal of area, maggot debridement and antioxidants
Where do nerve fibres travel after the optic nerve, what lays near to this structure and what related disease can cause a symptom?
Nerve fibres travel from optic nerve into optic chiasm. Pituitary gland lays directly below optic chiasm so pituitary tumours can cause bilateral loss of peripheral receptive fields
What group of nerves innervates the lower limb muscles, what spinal roots give sensory innervation to anterior and posterior lower limb and what dermatomes are on the knee, big toe and little toe?
Nerves from lumbosacral plexus. Anterior lower limb from lumbar spinal roots and posterior lower limb from sacral spinal roots. Knee - L3, big toe - L5, little toe - S1
What are the types of nerve damage from least to most serious?
Neurapraxia - temporary loss of motor and sensory function due to blockage of nerve conduction, myelin not intact but axon and epineurium intact Axonotmesis - disruption of axons resulting from severe crush or contusion, myelin and axons not intact and causes Wallerian degeneration but is reversible Neurotmesis - both axons and nerve sheath are disrupted so myelin, axon, epineurium aren't intact and Wallerian degeneration occurs so irreversible
How do neurons vary in different parts of the cortex, what do focal cortical lesions allow and what are association cortexes?
Neurons vary in type and density. Focal cortical lesions allow identification of separate functional regions in the cortex for each main sensory modality. Association cortexes integrate incoming info and form connections
What are the potential methods of CNS lesion treatment?
Neuroprotection to contain effect of early trauma, inflammation and scar formation. Promotion of axonal regeneration gives positive trophic support by counteracting inhibitory influences. Guiding axonal regrowth
What are the different methods of neurotransmission and which are fastest/slowest?
Neurotransmission (fastest, use direct gating of ion channel), neuromodulators (medium, use GPCRs) and neurotrophic factors (slowest). Fast neurotransmission uses multimeric receptors that incorporate ion channels and GPCRs comprise 7 transmembrane spanning segments
Where is the intervertebral foramen and what happens to this during flexion/extension?
Next to facet joints. Foramen opened in flexion but narrowed by superior articular processes of lower vertebra in hyperextension to compress nerve
Where do nociceptor and touch receptor fibres run and project to and which allows to localise pain?
Nociceptor fibres run in lateral STT and project to various nuclei in brainstem. Touch receptor fibres run in anterior STT and project to VPL. Anterior STT allows pain localisation as projects to somatosensory cortex
What epithelium is found in oesophagus and why, what muscles move during swallowing and what types of muscle are found in the oesophagus?
Non-keratinised stratified squamous cell epithelium for protection against abrasion. Swallowing involves relaxation of cricopharyngeal part of inferior constrictor muscle. Upper 1/3 made from skeletal muscle and lower 2/3 made from smooth muscle
What are paraneoplastic syndromes?
Non-malignant disease caused by malignancy due to peptide, hormone or cytokines production. Can involve endocrine, neurologic, dermatologic and haematologic systems
What are nicotinic receptors/NACHRs?
Non-selective cation ion channels that cause depolarisation of skeletal muscle and muscle contraction. Allow entry of Na+
Describe the structure and function of smooth muscle
Non-striated, involuntary muscle with long spindle shaped cells. Single nuclei and provides control of organ systems
What NT acts on alpha receptors, what are the types of alpha receptors and drugs that act on them to reduce BP?
Noradrenaline. A1 - vascular smooth muscle contraction. A2 - inhibits noradrenaline release. A1 antagonist (prazosin, alfuzosin) or A2 agonist (clonidine)
How does the sympathetic nervous system control BP using hormones?
Noradrenaline/adrenaline bind to beta receptors on JG cells to stimulate renin release. Renal nerve (sympathetic efferent) increases renin release
What is normal CSF pH, why are H+ sensors found in the brain and what happens to this system in COPD patients?
Normal CSF pH - 7.32. H+ sensors in brain as no proteins in CSF to buffer pH changes unlike in blood so change in pH greater for a given change in pCO2 in blood. In COPD patients, chronically elevated pCO2 means central chemoreceptors are less sensitive so drive for ventilation from CO2 is reduced and hypoxic drive dominant.
What changes happen to the vocal cords for normal and deep respiration, phonation and whispering?
Normal respiration - laryngeal muscles relaxed and rima glottidis forms narrow slit Deep respiration - vocal ligaments abduct Phonation - vocal ligaments and arytenoids adduct Whispering - vocal ligaments adduct but arytenoids relax
What is the normal serum Ca level and what is maintenance of a normal serum Ca level dependent on?
Normal serum Ca - 2.2-2.6mmol/L. Maintenance of a normal serum [Ca] dependent on intestinal absorption, renal excretion and skeletal mobilisation
What is muscle tone and how do LMN and UMN lesions affect this?
Normal, slight resistance to passive movement LMN lesion - reduced/completely absent tone (flaccid paralysis) UMN lesion - hyperreflexia and pathological increase in muscle tone (spasticity)
What is the normal intraocular pressure, where is visual acuity highest and what is the blind spot?
Normally 10-21mmHg. Visual acuity highest in fovea in centre of retina. Blind spot has no photoreceptors and found where visual axons leave eye to form optic nerve
What colour is normal synovial fluid, what is the normal pH, what does it contain and what causes hemarthrosis?
Normally clear with pH of 7.38. Contains ions, proteins (globulins, albumin), glucose, WBCs, HA and lubricin (both from type II synoviocytes). Hemarthrosis caused by damage to synovial membrane which allows capillaries to bleed into joint
What are spare receptors?
Not all receptors needed to produce full response so spare receptors increase sensitivity and speed of responsiveness to ligand. Competitive inhibitors remove spare receptors
What is a nucleus, column, tract, ganglion and nerve?
Nucleus - group of related nerve cell bodies in CNS Column - group of related nerve cell bodies forming longitudinal column extending thorugh part or all of spinal cord Tract - bundle of parallel axons in CNS Ganglion - group of nerve cell bodies in peripheral nerve or root Nerve - bundle of axons or nerve fibres
Which part of the medulla receives input from pulmonary receptors, where does it project to for inspiration and what area stimulates forced expiration and how?
Nucleus of the solitary tract (NTS). Projects to dorsal respiratory area for inspiration and ventral medulla for forced expiration that activates internal intercostals via the reticulospinal tract
What changes occur in IVDs as we age?
Nucleus pulposus dries out (lose heigh, disc not as resilient and doesn't absorb shock as well) and annulus thickens and develops fissures and cavities so decreased diffusion
What is a herniated disc and what are the different types?
Nucleus pulposus pushed out through annulus fibrosus (mostly posteriorly) and can push into spinal nerves Protruding disc - bulge in disc but no rupture Prolapsed disc - pulposus forced into outer annulus but no rupture Extruded - pulposus bulging through hole in annulus Sequestered - pulposus fragment outside disc
How does oxygen reach the retina and how is worn-out membrane of photoreceptor recycled?
O2 diffuses into photoreceptors from choroid capillaries thorugh pigment epithelium. Cell sheds worn-out membrane at distal end which is phagocytosed by epithelial cells then transported into capillaries of choroid
What is oedema and what are the causes?
Oedema is swelling of the tissue due to accumulation of fluid in ECF. Caused by low capillary oncotic pressure (loss of plasma proteins), increased hydrostatic pressure, lymphatic obstruction or increased capillary permeability
What is the oesophagus, what can reflux cause, describe GORD and what can continuous reflux cause?
Oesophagus is muscular tube that propels food to the stomach. Reflux can cause oesophagitis. GORD - heartburn, positional, poor correlation with symptoms and must differentiate angina. Continuous reflux can cause Barrett's oesophagus (pre-malignant adenocarcinoma)
What is the effect of oestrogen and glucocorticoids on Ca metabolism and what can prolonged corticosteroid treatment/menopause cause?
Oestrogen increases gut Ca absorption and inhibits osteoclasts. Glucocorticoids decrease Ca absorption and increase reabsorption due to osteoclast activation. Prolonged corticosteroids and menopause (decreased oestrogen) can cause osteoporosis
What is the general result of brainstem damage?
Often results in ipsilateral sensorimotor involvement of CNs and contralateral sensorimotor involvement of body functions
What causes subarachnoid haemorrhage and what is a symptom?
Often ruptured aneurysm and is arterial. Causes thunderclap headache
What are essential fatty acid examples?
Oleic acid (cis and trans because of C=C) and linoleic acid are essential as we can't synthesise them
What are oncogenes and proto-oncogenes and how do they regulate cell proliferation?
Oncogenes (dominantly active) are mutated proto-oncogenes. Regulate cell proliferation by encoding growth factors (genes often amplified), growth factor receptors or signalling molecules
Describe saddle joints, what movements do they allow and where are they found?
One bone is saddle shaped and other is a rider to allow flexion/extension, abduction/adduction and circumduction. Found in carpometacarpal joint of thumb
What is a characteristic of walking and what is the major propelling force?
One foot always in contact with the ground and major propelling force is falling forward
What are disadvantages of XRs for imaging the skeleton?
Only calcified tissue shows up (soft tissue doesn't show well and not very sensitive as 30% bone mass loss required before changes visible) and bone can obscure internal processes and structures behind
What cells are found in fovea, what do they allow and what are rods?
Only cones found in fovea (mediates ability to see detail when active in daylight) Rods are very sensitive to light and are active when dark and have no colour differentiation
What are the types of glaucoma?
Open angle/simple chronic - slowly progressive and occurs when trabecular meshwork becomes blocked Primary angle closure/acute glaucoma - angle between cornea and iris reduces so flow of fluid inside eye can't pass through canal of Schlemm, causing rapid rise in pressure
What is the K+ VGC and what does it do?
Open in response to depolarisation (opens slower than Na+ and remain open during whole depolarisation) and cause repolarisation/hyperpolarisation
When and how do AV valves open and close?
Open when atrial pressure > ventricular pressure during diastole and close when ventricular pressure > atrial pressure during systole to prevent backflow. Close when papillary muscles contract to pull chordae tendineae
When are epiphyseal growth plates open/active until, what bone is first and last to ossify and how does it develop?
Open/active until 18-25yo. Clavicle is 1st and last bone to ossifiy and develops using both endochondral and intramembranous ossification
What are the main branches of the ICA and what do each of these do/supply?
Ophthalmic - supplies orbit and retina PCoA - connects carotid and vertebral artery systems MCA - supplies basal ganglia and internal capsule and lateral 2/3 of cortex ACA - supplies internal capsule and medial side of frontal and parietal lobes
What is the reverse of glucokinase and phosphofructokinase in gluconeogenesis and how is glucose made from glycerol?
Opposite of glucokinase is glucose-6 phosphatase and opposite of phosphofructokinase is fructose-1,6-bisphosphatase. Glucose made using glycerol using fructose-1,6-bisphosphatase
What does damage to optic nerve, optic chiasm and optic tract cause?
Optic nerve damage - monocular vision loss in respective eye Optic chiasm - bitemporal hemianopia (tunnel vision) Optic tract - homonymous hemianopia (loss of l/r visual field in each eye)
What are the different routes of administration and their time to effect?
Oral - cheapest and most available but 10-50% availability (30-90mins), IV - 100% bioavailability (30-60secs), IM - drug released slowly into system (10-20mins), sublingual - enters blood directly and bypasses 1st pass metabolism (3-5mins), intrathecal - into BBB and bypasses BBB, inhaled - directly to lungs then bloodstream (2-3mins), rectal - goes to liver (5-30mins), transdermal - applied to skin and crosses skin to enter systemic blood supply, topical - local effect, intranasal - can be local or systemic, epidural - outside spinal dura, intra-articular - into joint space
What is found in the alimentary tract and what epithelium lines each part?
Oral cavity (stratified squamous), simple passages (oesophagus and anus with non-keratinised stratified squamous) and digestive tract (mucosal glands and accessory glands and secreting/absorptive cells)
What are lysosomes and how can they cause disease?
Originate from Golgi, defence against disease (macrophages), for autophagy (cell organelles) and apoptosis. Tay Sachs from inability to break down gangliosides
What are osmolarity and osmolality and what is the normal body fluid osmolality?
Osmolarity - osmoles of solute per L of solution, osmolality - osmoles of solute per Kg of solvent. Normal osmolality is 290-300mosmol/Kg H2O
Where are osmoreceptors found and what do they do?
Osmoreceptors found in hypothalamus in supraoptic and paraventricular nuclei which send axons down pituitary stalk to end on capillaries in posterior pituitary and secrete ADH
What are osteoclasts, what stem cells do they come from and what is their process of differentiation?
Osteoclasts are related to macrophages and are bone remodellers. Come from haemopoietic stem cell lineage Granulocyte-macrophage colony forming unit --> osteoclast precursor --(RANKL)--> osteoclast --(IL-1)--> activated osteoclast
What is the external oblique muscle, what direction do its fibres run, where does it attach and where does it stop?
Outermost muscle of lateral abdominal wall. Fibres run in antero-inferior direction and attach superiorly to ribs and inferiorly to iliac crest. Becomes aponeurotic at midclavicular line
How does the RF control breathing?
Output via nucleus ambiguus (nAmb) and surrounding RF in ventral medulla Medullary pacemakers generate rhythm Pneumotaxic centre facilitates expiration and limits inspiration Apneustic centre facilitates inspiration and limits expiration
Describe ellipsoidal/condyloid joints, what movements do they allow and where are they found?
Oval shaped condyle fits into elliptical cavity of another bone to allow flexion/extension, abduction/adduction and circumduction. Found between carpals and radius
What do J receptors respond to, what do they do and what symptom does stimulation of these receptors cause?
PE, pulmonary oedema, barotrauma, pneumonia and congestive heart failure. Chemoreceptors that detect fluid in alveoli and send afferent signals via vagus to stimulate increased respiratory rate. Stimulation causes sensation of dsypnoea
How are inherited metabolic diseases screened for?
PKU and MCADD tested for by heel-prick test. Plasma metabolite analysis using mass spec looks for build-up of abnormal metabolites. Also screening of family members for specific genotypes
What causes phenylketonuria, what does high phenylalanine levels cause, symptoms and treatment?
PKU caused by defect in phenylalanine hydroxylase or dihydrobiopterin reductase (dihydrobiopterin is a cofactor so 2y cause) so unable to convert phenylalanine --> tyrosine. High phenylalanine causes side reaction to form phenylpyruvate and phenylethylamine (both toxic) and also excretion of phenylalanine/side reaction products in urine. Symptoms - developmental delay, eczema, hyperactivity and mental retardation
How do PNS and SNS affect airway smooth muscle?
PNS causes smooth muscle contraction by ACH release from postganglionic neurons onto MACHRs. SNS works by circulating catecholamines activating beta 2 receptors
Where are Peyer's patches found, what are they and what immune cells does a normal intestine have?
PPs found in gut luminal surface and are lymph nodes. Normal intestine has T cells and IgA plasma cells. CD4 populates lamina propria and CD8 populates epithelia
When is PTH released, what does it promote and how?
PTH released when [Ca] is low. Promotes Ca reabsorption in the kidney, renal synthesis of 1,25(OH)2 vitamin D that increases gut Ca absorption and increases number/activity of osteoclasts to reabsorb Ca from bone (causes RANKL expression on osteoblasts that binds to RANK receptor on osteoclast precursors)
What happens to PTH secretion when Ca range is normal, where is calcitonin released from and what does it do?
PTH secretion stops when [Ca] is within range. Calcitonin is released from C cells in the thyroid gland and deactivates osteoclasts, increases renal Ca excretion and increases amount of Ca that bone can accept
What is Klinefelter syndrome?
XXY, 1 in 1000 males. Causes infertility, faulty development of 2ndy sexual characteristics, tall.
How does disc herniation cause pain?
Pain comes from surrounding structures. Compressed ligaments causes localised pain and compressed nerve roots causes numbness, tingling and pain in relevant dermatome
What is referred pain?
Pain from internal organs felt in region of body surface that has afferent input in same spinal segment (dermatome) that active visceral pain fibres terminate
What causes neuropathic pain?
Pain programs becoming spontaneously active so pain is felt but no injury is present
What does the spinothalamic tract transmit, where is it found and what is the pathway that its neurons take?
Pain, temperature and crude touch from spinal cord to thalamus. Found anterior to ventral horn of grey 1y sensory neuron synapses with 2y neuron that decussates (crosses midline) then travels up tract. Synapses with 3y neuron in thalamus that travels to 1y somatosensory cortex
What is the crossed extensor reflex and how does it work?
Painful stimulus in one leg causes flexion reflex in that leg and extensor contraction in opposite leg. Afferent nerve fibres from stimulated side switch to contralateral spinal cord and synapse with interneurons that excite/inhibit a motor neurons to muscles of opposite limb
What are the parts and nervous supply of a serous membrane?
Parietal (somatic innervation, surrounds cavity) and visceral (visceral innervation, covers organs) membranes with serous fluid inbetween for reduced friction.
Describe the nerve supply to the visceral and parietal peritoneum and how is pain felt in each?
Parietal peritoneum has somatic nerve supply from the abdominal wall so pain is well localised. Visceral peritoneum has visceral nerve supply so pain is often referred to relevant dermatome (only sensitive to chemical irritation and stretch)
What are visual fields, what part of the visual cortex sees which visual field, where do the nasal and temporal hemiretina that see left visual field project to and where do the axons decussate?
Part of vision to left/right of fixation point. Right cortex sees left visual field. Nasal hemiretina of left eye (decussates in optic chiasm) and temporal hemiretina of right eye see left visual field and project to right visual cortex Axons decussate in optic chiasm
What are the consequences of a partial optic nerve lesion, complete optic nerve lesion, optic chiasm lesion and optic tract lesion and why are lesions often macular sparing?
Partial optic nerve lesion - ipsilateral scotoma (patch of blindness) Complete optic nerve lesion - blindness in that eye Optic chiasm lesion - bitemporal hemianopia Optic tract lesion - homonymous hemianopia Lesions often macular sparing as has bilateral projection to visual cortex
How does altitude affect gas exchange and pO2?
Partial pressure of O2 remains the same but total pressure decreases so less saturation of Hb in lungs so altitude sickness develops if respiration rate not increased
What is the course of the olfactory nerve from the nose to the brain and what does it convey?
Passes through cribriform plate of ethmoid bone then through olfactory bulb and back into olfactory tract. Contains special sensory fibres that convey sense of smell
How is weight distributed in the foot in quiet stance and how do the arches not collapse?
Passes through talus and equally backwards/forwards Arches are supported by tendons, bones and ligaments to prevent collapse
What factors creates resting membrane potential?
Passive leak channels (more K+ and larger so more K+ leaves than Na+ enters), active ionic transport (Na+/K+ ATPase) and Gibbs-Donnan eqm (presence of impermeant, charged molecules influences distribution of small permeant molecules). Large -ve proteins attract K+ back in
What are the functions of the patella and collateral ligaments, where does patella sit (and how does this contribute to dislocations) and where is patella pulled if either the quadriceps or patella tendon rupture?
Patella and collateral ligaments stabilise the knee joint. Patella sits anterior to femoral condyle and slightly laterally (more likely to dislocate laterally). If quadriceps/patella tendon ruptures then patella pulled in opposite direction
What is germ theory?
Pathogens present in case of their disease, cause disease when given to healthy individual and must be re-isolated from new host same as originial
What are the details checked?
Patient name and DOB, date/time of image and previous imaging
What is severe combined immunodeficiency (SCID)?
Patients have no lymphocytes so babies have recurrent bacterial, viral or fungal infections. Treatment is bone marrow transplant
What are the functions of pectoralis major and minor and what innervates them?
Pectoralis major has a function in adduction, flexion and medial rotation and pectoralis minor has a function in stabilising the shoulder joint. Both innervated by pectoral nerves
What is ejection fraction, its normal value and how is HF diagnosed?
Percentage of blood leaving heart. Normal is 55-70%. HF diagnosed using clinical history, physical examination, ECG then BNP and echo
How does perfusion differ in different lung zones?
Perfusion is greatest in bases and least in apex due to gravity. Zone 1 (apex) - intermittent flow only during systole and flow ceases during expiration. Zone 2 - pulsatile flow where flow greater in systole than diastole. Zone 3 (base) - continuous flow
What are pharmacokinetics and pharmacodynamics?
Pharmacokinetics - how body interacts with drug. Pharmacodynamics - how drug interacts with body
What is the function of the posterior compartment of the leg, what are the muscles and what is the innervation?
Plantarflexion and toe flexion (tibial nerve) Superficial muscles (attach via calcaneal tendon) - gastrocnemius, soleus and plantaris Deep muscles (attach to bones of foot) - tibialis posterior, flexor digitorum longus and flexor hallucis longus
What is plasma, what is found in it and what does serum not contain?
Plasma is the cell-free part of blood (contains albumin, clotting factors, globulins, water, glucose and electrolytes). Serum doesn't contain clotting factors
Describe plasmid addiction
Plasmid genes code for toxins and antitoxin. Antitoxin degraded by cell but toxin isn't. If daughter cell doesn't have plasmid, can't synthesise antitoxin so cells are self-poisoned. Addiction systems on same plasmid as resistance genes
What are plicae circulares and what are villi and microvilli?
Plicae circulares are circular folds including submucosa in jejunum and ileum. Villi are extensions of mucosa and have central core of lamina propria with central lacteal (lymphatics). Microvilli are apical processes on cells to form brush border
What does polarised light show in the bone, what do osteons do and how do collagen fibres provide strength?
Polarised light shows direction of colalgen fibres. Osteons run down cortical bone to give strength and collagen fibres provide more strength by running in different directions
What are glycoproteins?
Polypeptide attached to oligosaccharide that can form receptors and give strength. Mucin attracts water to form mucus. Fibronectin for cell adhesion, migration and shape. Laminin for cell adhesion to BM and attaches cytoskeleton to collagen
What makes up the posterior and anterior triangles of the neck and what sub-divisions are found in each?
Posterior - posterior SCM, clavicle and trapezius. Divided into occipital and supraclavicular triangles Anterior - anterior SCM, midline of neck from chin to jugular notch and lower border of mandible to mastoid process Divided into carotid, muscular, submental and submandibular triangles
What forms the posterior 1/3 of the tongue and what innervates the anterior and posterior parts of the tongue?
Posterior 1/3 made from vallate papillae then lingual tonsils. Anterior 2/3 - special sensory from chorda tympani (branch of facial) and general sensory from lingual nerve (V3) Posterior 1/3 - both special and general sensory from glossopharyngeal nerve"
What are the boundaries of the carotid triangle and what structures are found within it?
Posterior belly of digastric, superior belly of omohyoid and anterior SCM. Highly vascular with common carotid and IJV. Also contains CN IX, CN X, CN XI, CN XII, cervical sympathetic trunk and ansa cervicalis
What muscles are found in the posterior forearm and how do the tendons insert into the fingers?
Posterior forearm contains finger extensors (extensor digitorum communis, extensor digiti minimi and extensor indicis). Tendons insert onto dorsal surface of fingers via dorsal expansion (fibrous tissue)
Describe the blood supply to the thoracic wall
Posterior thoracic wall takes blood supply from posterior intercostal arteries from descending aorta (3-12) or costocervical trunk off subclavian (1-2). Anterior thoracic wall takes blood supply from anterior intercostal arteries from internal thoracic artery (runs deep to costal cartilage and from subclavian)
What is a power grip and what muscles are used for this grip?
Power grip where all fingers flex around an object so all muscles that close the hand are active. Hypothenar muscle stabilises medial palm, wrist extensors provide a stable base. Includes cylindrical, spherical and hook grips
What are prebiotics, where are they found, what are probiotics and what are their roles?
Prebiotics stimulate growth and survival of gut bacteria and are found in non-digestible food ingredients (eg. fructans and galactans). Probiotics are live cultures found in dairy products or fermented food and have a role in maintaining normal microbial quorum needed for healthy epithelium, ENS and immune activity
What is a precision grip and what muscles are used for this grip?
Precision grip where object held between thumb and fingers. Involves intrinsic muscles of the hand which cooperate with long flexor and extensor muscles
What NT and receptors are found/used in SNS pre- and postganglionic neurons?
Preganglionic uses ACH onto NACHRs and postganglionic uses noradrenaline onto a1 adrenoreceptors on smooth muscle
What movement do prehensile grips require and what is the only non-prehensile grip?
Prehensile grips require thumb opposition. Hook grip is the only non-prehensile grip
What is the function of auditory reflexes?
Prevent damage to person/ear and distinguish important sounds from background
What is botox?
Prevents ACH release so causes muscle spasms, excessive sweating and overactive bladder
What does anterior ileofemoral ligament prevent and how and why are posterior ligaments weaker?
Prevents over-extension of the hip joint as it becomes taut to hold femoral head in acetabulum and then relaxes when the hip flexes. Posterior ligaments are weaker as they don't completely cover the NOF
What is the function of the Eustachian tube?
Prevents pressure difference on either side of eardrum that would compromise function
What is important about the arrangement of the ossicles?
Prevents vibrational energy from being reflected away from inner ear
What are primary and secondary lymphoid organs?
Primary - bone marrow and thymus. Secondary - lymph nodes and spleen
What are primary and opportunistic pathogens, infections, pathogenicity and virulence?
Primary pathogens - cause disease when infect organism (not normally associated), opportunistic pathogens - only infect when immunocompromised
What are pro-carcinogens, ultimate carcinogens and example in cigarettes?
Pro-carcinogens (polycyclic aromatic hydrocarbons) need to be metabolised/oxidised to ultimate carcinogen (eg. using CYP450). In cigarettes, BDPE forms DNA adducts with guanosine residues in lung epithelial cells
What is alternative splicing?
Process by which different exons are removed, so many proteins can be coded for by one gene (eg. alpha tropomyosin)
What is the Cori cycle?
Process of lactate formation and metabolism during exercise. Exercising muscle create lactate from glucose that is secreted into blood which is then taken up by liver and anabolically converted to glucose which is then secreted into blood
How do RBCs produce ATP, how do they produce NADPH, how do they protect against oxidative damage and where are old RBCs removed?
Produce ATP from glycolysis and NADPH via pentose phosphate pathway using glucose from Glut1. Contains antioxidants and old RBCs phagocytosed in liver, spleen and bone marrow
What is the role of septal cells/type II pneumocytes?
Produce surfactant made from phospholipoprotein dissolved in water. Decreases surface tension in alveoli and prevents collapse during expiration
How can endotoxins affect the body?
Produced by Gram -ve and causes overreaction of immune response and host damage. Gram -ve lysis --> LPS binds to LPS binding protein --> macrophages produce cytokines --> endotoxic shock
What produces the stability of the hip joint?
Produced by deep insertion of femoral head into acetabulum, ligaments that surround the joint, strong and tight articular capsule, large and powerful muscles around the joint, ligaments within articular capsule and a fat pad that fills the central region to add cushioning for thinnest part of acetabulum
How does the RF modulate via ACH?
Produces cortical arousal and sensory filtering through thalamic projection
Wha does the stomach produce how are stomach ulcers treated and what is the cause of most peptic ulcers?
Produces gastric acid, intrinsic factor, gastrin and pepsinogen. Stomach ulcers treated using histamine antagonists or proton pump inhibitors. Most peptic ulcers caused by H. pylori
How does glucagon-like peptide 1 (GLP-1) control feeding behaviour?
Produces rapid satiety by acting on POMC/CART neurons in arcuate nucleus and inhibiting gastric emptying
What causes hallux valgus?
Progressive movement of big toe towards 2nd toe Mainly inherited but also due to tight pointy shoes
How is RF involved with ANS and what happens if reticulospinal tract damaged?
Projects to preganglionic ANS neurons (both SNS and PNS) Damage causes loss of ANS output so loss of BP and temperature regulation and bladder/bowerl control
What are prokaryotes, eukaryotes and viruses?
Prokaryotes - unicellular with no nuclear membrane (eg. bacteria and archae that live in extreme environments and no peptidoglycan). Eukaryotes - nuclear membrane (eg. human cells, fungi, protozoa, algae, arthropods and worms). Viruses - non-living, have DNA or RNA and dependent on host cell
What is aqueous humour, where does it circulate and how does it drain?
Protein-free filtrate of blood that is formed in posterior chamber by ciliary body and circulates over anterior surface of lens and into anterior chamber. Drains into canal of Schlemm
What are proteoglycans, what is the major proteoglycan in articular cartilage and what cell makes the cartilage ECM?
Proteoglycans are heavily glycosylated glycoproteins. Major proteoglycan is aggrecan and chondrocytes make the cartilage ECM (mainly H2O but also proteoglycans and colalgen type II)
How are drugs excreted?
Protonated/lipophilic drugs move into blood from kidney, weak acid drugs excreted faster in alkaline urine as more in unprotonated form. Tricyclic antidepressant (acidic) overdose treated by alkalinising blood with HCO3- so doesn't diffuse into blood
What does the innate immune system do?
Provides first line of defence, alerts immune syste, to presence of pathogen (inflammation) and activates adaptive immune response
What is the function and characteristics of tears, and how do they exit the eye?
Provides optically smooth refracting surface and contains antibodies and lysozyme to prevent bacterial growth. Tears exit eye via lacrimal punctum and drain into nasolacrimal duct
What are found upstream of start of gene?
Proximal promoter region/TATA box (for binding of RNA polymerase) and distal regulatory elements (enhancer region for binding of transcription factors)
What joints are found in the elbow and what joints do flexion/extension use?
Proximal radioulnar joint, humeroradial and humeroulnar joints. Flexion and extension use the humeroradial and humeroulnar joints
What is Romberg's test?
Pt stands upright with heels together and closes eyes to assess proprioception. +ve sign is inability to balance (sensory ataxia)
What is the blood supply to the lungs, where do they come from and what is the venous drainage?
Pulmonary and bronchial arteries (supply trachea and bronchi). Bronchial artery comes from aorta. Right bronchial vein drains into azygos vein and left bronchial vein drains into hemiazygos and accessory azygos into RA, whilst pulmonary vein drains into LA
What is found in the lung hilum and what is the relation between pulmonary arteries and veins?
Pulmonary arteries/veins and bronchus. Arteries are superior to veins
What is the Na+/K+ ATPase?
Pump of Na+/K+ using energy from ATP. Na+ pumped out of cell and K+ pumped in. Can affect cell volume and can be inhibited with toxins
What does airway pushing/pulling indicate?
Pushing - mass, pneumothorax or effusion due to increase in pressure. Pulling - collapse due to decrease in pressure
What causes pyruvate dehydrogenase deficiency, what is its inheritance pattern, symptoms and treatment?
Pyruvate dehydrogenase deficiency caused by defect in PDC genes. Has X linked or autosomal recessive inheritance. Symptoms - seizures, mental retardation, hypotonia, brain wasting, lactic acidosis, vomiting, breathing problems and arrhythmia. Treated using thiamine, lipoic acid and ketogenic diet to provide alternate energy source
How is pyruvate converted to phosphoenolpyruvate?
Pyruvate transported into mitochondria --> pyruvate carboxylase converts pyruvate into oxaloacetate (uses ATP and CO2) --> oxaloacetate converted to malate using malate dehydrogenase (produces NAD) --> malate transported out of mitochondria --> malate converted to oxaloacetate using cytoplasmic malate dehydrogenase --> oxaloacetate converted to PEP using phosphoenolpyruvate carboxykinase
What is the function of quadriceps, what does gluteus maximus do, what is its innervation, what do the hamstrings do and what are their innervation?
Quadriceps are weak hip flexors and stabilise the knee joint. Gluteus maximus (innervated by superior gluteal nerve) is major hip extensor. Hamstrings (innervated by tibial branch of sciatic nerve) are weak hip extensors
What causes rheumatoid arthritis, what colour is synovial aspirate in this condition and what does it cause?
RA caused by autoimmune response which produces antibodies against synovial membrane. Synovial aspirate is cloudy colour due to inflammatory response. Causes type II synoviocyte proliferation, synovial membrane thickening and lymphocyte infiltration
Why are diuretics used for RAAS abnormalities and how do loop, thiazide and aldosterone antagonists work?
RAAS overstimulation causes excess water reabsorption so diuretics help excrete salt and water. Loop diuretics inhibit NKCC2 in ascending limb, thiazide diuretics inhibit Na-Cl cotransporter in DCT and aldosterone antagonists inhibit Na/K exchange in collecting duct so are K sparing
What are the radial and ulnar collateral ligaments, what is the anular ligament and how can a feature of this cause a dislocation?
Radial and ulnar collateral ligaments are triangularly shaped ligaments that connect to humerus. Anular ligament encircles radial head from ula to create proximal radioulnar joint. Quite loose in children so can cause subluxation (partial dislocation)
Where do radial, median and ulnar nerves gives sensory innervation to in the hand?
Radial nerve - lateral dorsum of hand Median nerve - lateral palmar hand surface Ulnar nerve - medial side of dorsal/palmar hand
How does the radial nerve run through the arm and what injury can damage it?
Radial nerve runs on posterior aspect of humerus then pierces intermuscular septum to run anterior to lateral epicondyle then back into posterior compartment. Mid-shaft humeral fractures can damage the radial nerve
Where does the radial nerve run in the arm, elbow and forearm, what does it give sensory/motor innervation to and what injury can damage the radial nerve?
Radial nerve runs on posterior humerus in radial groove (between radial and lateral heads of triceps). Passes into anterior elbow then back into posterior forearm to give motor innervation to extensors and sensory innervation to hand dorsum. Damage mainly caused by mid-humeral shaft fractures
Where do you locate the radial and ulnar pulses?
Radial pulse found lateral to tendon of flexor carpi radialis and ulnar pulse found lateral to tendon of flexor carpi ulnaris but is harder to find as runs deeper and under pisiform and palmar fascia
What is sentinel node biopsy?
Radioactive tracer given near tumour site and histological analysis of lymph nodes taking up tracer to establish if cancer present
What is Michaelis Menten equation and what does Km value show?
Reaction rate V is number of reactions/sec catalysed per mole of enzyme. Relates initial rate (V0) to [S] until Vmax (maximum rate of reaction). Lower Km value shows faster rate of reaction. Km = [S] at Vmax/2
What is the ready, steady, go model of movement?
Ready - posterior parietal cortex decides to move and the functional consequence of action Steady - motor association cortex stores plans to move until required Go - 1y motor cortex gives instruction to move by activating descending pathways
What are nuclear receptors?
Receptors found in cytoplasm. Ligand diffuses through PM, binds to and activates nuclear receptor that activates transcription
How are receptors used in the immune system?
Receptors transmit signals from cell surface to nucleus to change gene expression and function. Can have interactions with other cells, antigens and soluble mediators (cytokines and growth factors)
What are tumour suppressors, how do mutations cause cancer and what is Bax?
Recessively active and restrict proliferation by controlling cell cycle and inducing apoptosis. Mutations release cells from growth factor control and may prevent apoptosis. Bax is a pro-apoptotic signal
How does the innate immune system work?
Recognises lipopolysaccharides (LPS) on microbes using toll-like receptors (TLRs). TLR4 activation from bactieral LPS causes inflammatory response to clear infection
Describe the blood supply to the rectum
Rectum has blood supply from superior rectal artery (from IMA), middle rectal artery (from internal iliac artery) and inferior rectal artery (from pudendal artery)
Where do the rectus and oblique muscles insert?
Rectus muscles insert anterior to equator and oblique muscles insert posterior to equator. Rectus muscles insert more medially to posterior orbit than they attach to eye so affects direction that superior/inferior rectus muscles pull eye
Describe the innervation of the larynx
Recurrent laryngeal (right passes under r. subclavian artery and left under arch of aorta) is motor innervation to all intrinsic muscles except cricothyroid and sensory to area below vocal cords. Superior laryngeal nerve branches to form external (motor to cricothyroid muscle) and internal (sensory to area above vocal cords) laryngeal nerves
What is the function of reduced coenzymes and how does ETC make ATP?
Reduced coenzymes transport electrons and become oxidised to feed electrons into ETC. ETC makes ATP by using electrons to pump H+ into intermembrane space and then using energy stored in proton gradient to drive ATP synthesis
What is a possible cause of anorexia nervosa?
Reduced pleasure from smell/taste of food and reduced pleasure from orofacial activity
How is the baroreceptor reflex different in hypertensive patients?
Reference point is higher or feedback signal from carotid sinus decreased so higher BP recognised as normal
What causes variations in the amplitude of venous return?
Reflection from RA back into vessels and due to respiratory pump (increased return during inspiration and decreased return during expiration)
What is the function of leptin?
Reflects total amount of adipose tissue in body so reflects total energy storage levels Doesn't rise rapidly so acts as long-term appetite regulator by increasing sensitivity to fast-acting satiety signals
How do lungs regulate acid-base balance and what is normal CO2?
Regulate by altering depth and rate of ventilations and retaining/eliminating CO2. Normal range - 4.7-6.0kPa
How is endogenous insulin production regulated?
Regulated at synthesis (transcription, mRNA stability, translation and post-translation modification) and secretion
How is cell cycle progression regulated?
Regulated by CDKs that are activated by cyclins. Different Cyclin-CDK complexes act on different parts of cell cycle
What is the enteric nervous system and what are the divisions?
Regulates GI function and has parasympathetic and sympathetic input. Divided into myenteric (controls motility) and submucosal plexi (controls muscle in muscularis and secretion)
What are the roles of the vascular endothelium?
Regulation of vascular tone, control of tissue blood flow, infllamatory response and maintaining blood fluidity
How do macrophages recruit neutrophils?
Release cytokines (IL-1, IL-6, IL-8, IL-12 and TNF alpha) that attract neutrophils. TNF alpha makes endothelium sticky by upregulating adhesion molecules. Neutrophils phagocytose bacteria and kill them using toxic mediators that can damage normal tissue. Use pattern recognition receptors (PRRs such as TLRs) to recognise pathogen-associated molecular patterns (PAMPs like cell walls and flagella) and produce cytokines)
How do cells release energy stored in food molecules and how is this energy stored?
Release energy through a series of oxidation reactions and energy is stored in ATP or NADH that can be used throughout the cell
Where is aldosterone released from, what does it act on and how does this increase blood volume?
Released from adrenal cortex and acts on ENaC in DCT. Stimulates reabsorption of Na into ISF, drawing water with it and increasing blood volume
How does ghrelin control feeding behaviour?
Released from fundus when stomach contracts when empty to generate sense of hunger Stimulates AGRP and NPY-releasing neurons and inhibits POMC and CART neurons
Where is oxytocin released from and what is its function?
Released from posterior pituitary and stimulates milk let-down reflex (type of neuro-hormonal reflex) in lactating mother to cause peristalsis of smooth muscle in ducts to expel milk
How does cholecystokinin (CCK) control feeding behaviour?
Released into duodenum when chyme moves from stomach and acts on POMC/CART neurons in arcuate nucleus so satiety hormone
How does sympathetic outflow trigger sweat glands?
Releases ACH which triggers NO formation which causes local vasodilation, increasing blood flow so more water can pass out of blood and be secreted as sweat
How do cationic antimicrobial peptides work?
Remove cations from phosphate so destabilise outer bacterial membrane (Gram -ve) and cause leakage. Polymyxin B
What is airway resistance and how does asthma impact this?
Resistance to flow of gas through the airways. Asthma increases resistance due to smooth muscle contraction and swelling due to inflammation and mucus production
What are the stages of the action potential?
Resting state (Na+ and K+ VGCs shut)--> depolarisation (Na+ activation gate opens) --> repolarisation (K+ VGCs open and Na+ inactivation gate closes)--> hyperpolarisation (K+ remains open and Na+ resets)
How is retinoic acid formed from vitamin A, what is its function in gut immunology and how do gut effector T cells know where to go?
Retinol --> retinal --> retinoic acid. Retinoic acid has function in imprinting cells to home to gut mucosa from PP. Gut endothelial cells express MadCAM (ligand for a4b7 on gut-homing effector T cells)
When can an oxidation/reduction reaction be reversible and give an example?
Reversible when adding electron requires little energy. NAD+ + H+ + 2e- --> NADH
What structure is used for central venous puncture?
Right IJV used as has straight path into brachiocephalic vein and SVC
What is the course of the optic nerve from the eye to the brain and what does it convey?
Rods and cones feed into optic nerve which travels through optic canal of sphenoid into optic chiasm and optic tract. Contains special sensory fibres that convey vision.
What is the meaning of rostral and caudal?
Rostral - towards the nose Caudal - towards the tail
What is the function of the caudal and rostral RF wrt motor control?
Rostral RF modulates forebrain activity and caudal RF is for premotor coordination of lower somatic and visceral motor
What is RIPE?
Rotation - medial aspect of each clavicle in relation to spinous process. Inspiration - 5-6 anterior ribs visible in mid-clavicular line, lung apices, costophrenic angles and lateral rib edges all visible. Projection - PA or AP (if scapulae not projected then PA). Exposure - left hemidiaphragm visible and vertebrae visible behind heart
Describe pivot joints, what movements do they alllow and where are they found?
Round or pointed surface fits into ring formed by a bone and ligament to allow rotational movement. Found in radius with annular ligament of ulna and C1/C2
What direction do the collagen fibres run in the different zones of the articular cartilage?
Run parallel to articular surface in resting zone, run randomly in proliferative and hypertrophic zones and perpendicular to articular surface in calcified zone
Where does the ulnar a. run, what does it supply, what is its branch (and what does this supply) and where does the radial a. run and what does it supply?
Runs down medial aspect and supplies medial muscles of forearm. Branches to form common interosseous that supplies deep flexors and extensors of forearm. Radial a. runs lateral and supplies lateral muscles
Where does ACL run from, what does it prevent and what are the types of ACL graft?
Runs from anterior part of tibia then ascends anteriorly to attach to lateral part of the femoral intercondylar fossa to prevent anterior movement of the tibia Grafts can either be BTB (using patella, patella ligament and femur) or using hamstring tendon
Where does vertebral column run, how long is it, how many vertebrae are there and which are moveable?
Runs from the skull to the coccyx with a length of 72-75cm in adults. 33 vertebrae (7C, 12T, 5L, 5S (fused), 4C (fused)). Cervical, thoracic and lumbar are moveable
Where does the iliotibial band run, what bone is the common peroneal nerve with and where is hamstrings tendon found?
Runs laterally on thigh from iliac crest to tibia Common peroneal wraps around fibula Hamstrings tendon found in superior borders of popliteal fossa
How do some microbes evade immune system?
S. pneumoniae cell surface proteins disrupt complement activation. S. pyogenes proteins inhibit phagocytes. Some produce antiphagocytic enzymes or IgA proteases. S. aureus bind host antibodies in wrong orientation. Others hide in dead tissue
What are the retroperitoneal organs?
SAD PUCKER - suprarenal glands, aorta/IVC, duodenum (1st part), pancreas, ureter, colon, kidney, (o)esophagus, rectum
What is the pathway of conduction in the heart?
SAN --> across atria --> AVN (delayed) --> bundle of His --> Purkinje fibres --> across ventricles
What is a property of SAN cells and what are the stages of an action potential in them?
SAN cells are spontaneously active pacemaker cells. Initiated by opening of Na+ and Ca2+ channels. After action potential, K+ channels slowly close and Na+ channels open, creating progressive depolarisation that eventually reaches threshold
How do SNS and PNS affect the GIT, what innervates the GIT up to midgut and what innervates the hindgut?
SNS - inhibits digestion PNS - stimulates salivation, digestion, colon motility and urination/defecation. Vagus nerve innervates up to midgut and sacral PNS fibres innervate hindgut
How do SNS and PNS fibres travel to innervate the GIT?
SNS fibres travel via sympathetic chain to run through splanchnic nerves (greater, lesser and lumbar) and synapse in pre-aortic ganglion (either coeliac, superior/inferior mesenteric ganglion) PNS fibres directly innervate the gut
What is the effect of the SNS and PNS on the heart, how does this work and what is the intrinsic rate of the SAN?
SNS increases HR and inotropy by noradrenaline binding to B1 adrenoreceptors. PNS decreases HR by ACH binding to M2 receptors. SAN intrinsic rate is 100bpm
What are the sarcoplasmic reticulum and sarcolemma?
SR wraps around myofibril and terminal cisternae store Ca Sarcolemma forms T-tubules running around myofibril at each A band-I band junction between paired terminal cisternae to form triad
What is the ST segment and what can it diagnose and T wave?
ST segment shows time of whole ventricular depolarisation. Used to diagnose AMI. T wave shows ventricular repolarisation
What are the sclera, iris and conjunctiva?
Sclera - very vascular white part of eye Iris - heavily pigmented area that can constrict Conjunctiva - layer of epithelium that covers sclera and inner eyelids and contains goblet cells that produce mucus that mixes with tears
What is sclerostin, what is it produced by, how does it regulate bone formation and what other molecules trigger remodelling?
Sclerostin inhibits bone formation by active osteoblasts and is normally secreted by osteocytes. Osteocytes stop secreting sclerostin when they sense stress on the bone so lining cells reactivate to become active osteoblasts. Pro-inflammatory cytokines (eg. IL-1, IL-6, IL-17 and TNF) also trigger remodelling
What is diffusion weighted imaging and when is it useful?
Sensitive to H2O molecule diffusion so useful in stroke as diffusion restricted in dying cells
Where do sensory axons enter the spinal cord, where do they synapse (and what with) and where do motor neurons leave spinal cord?
Sensory axons enter through dorsal root and synapse with interneuron in dorsal horn of grey. Interneurons synapse with motor neurons in ventral horn of grey and leave spinal cord through ventral root
What provides sensory innervation to the pharynx, what muscles make up the pharynx, what is their motor innervation and function?
Sensory innervation to pharynx from glossopharyngeal nerve and made from superior, middle and inferior constrictor muscles with motor innervation from vagus nerve. Contract to push bolus to oesophagus
What are the functions of membranes?
Separate intra and extracellular environments, separate organelle contents from cytosol and allow diffusion of small, non-polar molecules
What are receptor tyrosine kinases?
Separated when inactive. When ligand binds, monomers join and are activated, allowing phosphorylation and activation of proteins
How can too many inflammatory cytokines cause disease (sepsis, toxic shock, cytokine storm)?
Sepsis - uncontrolled, systemic TNF production causes septic shock (loss of BP, fever, diarrhoea, death). Toxic shock from super-antigens that activate many T cells and drive cytokine overproduction. Cytokine storm from positive feedback
What determines the function of a protein and what are the roles of proteins?
Sequence of AAs which determines external chemistry and shape
What is the 1y structure?
Sequence of AAs, with a C terminus at COO- and N terminus at NH3+
What are dideoxynucleotides and how are they used?
Sequence-ending nucleotides that can be used to sequence DNA by binding to primer to replicate template strand
Where is the origin of serratus anterior, what does it have a role in and what innervates it?
Serratus anterior originates from medial border of scapula, wraps underneath scapula and inserts onto ribs. Has a role in protraction of the scapula and innervated by long thoracic nerve
What is the role of GAGs and proteoglycans?
Serve as gel to embed cells and fibrous proteins (collagen, elastin, fibronectin) serve for structure, strength, flexibility, adhesion and cell positioning
What is kwashiorkor and how can it cause oedema?
Severe malnutrition and deficiency in dietary protein. Hypoproteinaemia decreases OPc so causes putting oedema and water retention in gut. Hypoproteinaemia can also come from liver disease
What provides passive support to the foot?
Shape of bones (allows to interlock) and longitudinally arranged ligaments (long and short plantar and spring ligaments) that prevent separation
What is shuffling/Parkinsonian gait?
Short shuffling steps, rigidity in hip/knee extensors, stooped forward posture and reduced arm swing
What is grading and what are the grades?
Shows extent of differentiation and rate of growth. Grade I - well differentiated, grade II - moderately differentiated, grade III - mildly differentiated, grade IV - poorly differentiated
What is staging and what are the stages?
Shows extent of spread. T (1 - 4) - size and spread, N (0-3) - has it spread to lymph nodes, M (0-1) - has it metastasised. Letters can also be used (eg. M1a or M1b)
What is volume of distribution and how is it calculated?
Shows how much drug is in body compared to plasma. VD = amount of drug in body/plasma conc
What is Nernst equation and what does it shows?
Shows membrane potential when movement of ions due to conc gradient stops. Em = 61.5xlog([C]o/[C]i)
What is a G-protein-linked receptor?
Signal molecule binds to receptor and G protein activated which binds to and activates enzyme/ion channel. In MACHRs, ACH binds to receptor and activates GTP-binding protein which can interact with other molecules
What are the types of AP in smooth muscle?
Simple spike, spike followed by plateau or slow wave potentials (spikes on top of slow waves)
What are the structures of membrane proteins?
Single and multiple pass alpha helix, integral membrane proteins, rolled up beta sheet, anchored by amphiphilic alpha helix, attached to inner membrane by lipid anchors or associate via non-covalent interaction with real membrane proteins
What are frameshift mutations and what can they cause?
Single base added/deleted so shifts entire sequence and changes all mRNA so proteins rarely functional. Tay Sachs caused by point and frameshift mutation in beta-hexosaminidase
What is the structure and function of capillaries and what vessel merges into capillaries?
Single layer of endothelium with no smooth muscle and are site of exchange of nutrients and waste products. Terminal arterioles merge into capillaries
What are target protein mutations?
Single point mutations or post-translational modification prevent antibiotic binding
In what situations are skull XR, CT and MRI used for head imaging?
Skull XR - depressed skull fracture and penetrating injury CT - mostly acute setting MRI - occasionally acutely
Where are small and large NTs synthesised?
Small NTs - made in synapse and packaged in vesicles. Protein NTs - made in cell body and packaged and transported in vesicles (anterograde to synapse)
What are the steps of ATP generation?
Small amount of ATP from glycolysis of glucose to pyruvate in cytosol (substrate level phosphorylation). If oxygen present, pyruvate metabolised in mitochondria or if no oxygen to lactate. ETC if oxygen creates lots of ATP from PMF
What is the structure of fenestrated capillaries and what type of transport do they allow?
Small circular pores in endothelial cells with continuous basal lamina to allow relatively free passage of salts and water from plasma to tissue
What are miniature end plate potentials?
Small depolarisations of postsynaptic membrane caused by release of single vesicle into synaptic cleft. Release of NT without signal from axon but no AP fired as small depolarisations don't reach threshold
What is the small intestine and what are its functions?
Small intestine is from duodenum to terminal ileum. Contains villi to increase SA for absorption of CHO, proteins, fats and vitamins. Also has a role in immunity (contains GALT and Peyer's patches)
What are micronutrients and what do they include?
Small molecules that are required in very small amounts in the diet for essential functioning. Include vitamins (organic) and trace elements (non-organic)
What are chemokines?
Small polypeptides that have a role in chemotaxis. Chemokine release causes cell migration along conc gradient. Signal through GPCRs and receptors can bind multiple chemokines
What are the features of cervical vertebrae and specifically C1/C2?
Small with bifid spinous process and transverse foramen for vertebral arteries C1 - ring-shaped without spinous process C2 - odontoid process that articulates with C1 C1/C2 don't have vertebral body
What are the types of solutes, what have a stronger osmotic power, what is osmolality and normal range?
Solutes can be electrolytes (eg. Na, K, Cl) or non-electrolytes (glucose, lipids, creatinine, urea) and electrolytes have a stronger osmotic power. Osmolality is the amount of solute per Kg of solvent (normally 280-300mOsm/Kg)
What are the differences between the ANS and somatic nervous system?
Somatic acts on skeletal muscle using one neuron (heavily myelinated) and is only excitatory. ANS acts on cardiac, smooth muscle and glands using 2 neurons (lightly myelinated) and can be excitatory or inhibitory
Describe a typical reflex arc
Somatic/special/visceral sensory receptors detect change in environment, info sent to CNS for processing via sensory division of PNS. Motor division of PNS carries motor commands from CNS to peripheral nerves
What are the types of adaptation and where are they found?
Some neurons maintain magnitude (otoliths detecting head position). Others decay magnitude - slow adaptation (olfactory system, good for duration) or rapid adaptation (Pacinian corpuscles that measure vibration, good for intensity)
Where do some optic nerve fibres project to in midbrain, what is the function of this area and what can damage to this pathway cause?
Some project to superior colliculi in midbrain (necessary for tracking objects). Connects to medial longitudinal fasciculi (MLF) that links and synchronises oculomotor nuclei. Damage to this pathway causes difficulty in tracking moving onjects
What causes spasticity, rigidity and flaccidity?
Spasticity - increase in muscle tone due to loss of inhibition of a motor neurons Rigidity - increase in muscle tone due to loss of inhibition of y motor neurons Flaccidity - occurs when nerve of LMNs damaged
What is large intestine specialised for, how is it different, how is outer longitudinal muscularis propria different and what parts are retroperitoneal/peritoneal?
Specialised for salt and water absorption. Different as doesn't have villi and has more goblet cells. Outer longitudinal muscularis propria arranged in 3 bundles (teaniae coli). Posterior parts of ascending and descending colon are retroperitoneal but rest is peritoneal
What is specific malabsorption, give examples of genetic causes of disaccharidase deficiencies and how can these cause diarrhoea?
Specific malabsorption caused by failure of processes governing absorption of one class/type of nutrient. LCT gene affects mucosal phase whilst SLC5A1 encoding Na-dependent glucose transporter 1/SGLT1 causes glucose-galactose malabsorption. Cause osmotic diarrhoea as unabsorbed disaccharides reaching colon add to osmotic load. Sugar fermentation in intestine causes gaseous distension and further adds to watery diarrhoea
What are the steps of cell differentiation?
Specification - reversible process and can occur autonomously in neutral environment, determination - irreversible and can occur in any region
What are specificity and selectivity, potency and efficacy?
Specificity - which organ drug works on, selectivity - which receptor drug binds to, efficacy - drug's capacity to produce effect, potency - drug conc for given effect
What does the spermatic cord contain and describe the development of the testes?
Spermatic cord contains testicular artery and vein and vas deferens. Testes develop on posterior abdominal wall and then descend through inguinal canal at 7 months gestation to end in scrotum at 9 months
Where does spinal cord end in adults, what does it form at this level, where are the enlargements and what are the conus medularis and filum terminale?
Spinal cord ends at L1/L2 where it forms cauda eauina. Has cervical and lumbar enlargements. Conus medularis is where spinal cord tapers and filum terminale is made from neuroglial cells and anchors spinal cord
Describe the spinal cord and where does it start and end?
Spinal cord starts at C2 and ends at L1. White matter on outside, grey matter on inside. Info enters dorsal root and leaves ventral root
Describe the structure and function of cardiac muscle
Striated, involuntary muscle with similar contractile element structure to skeletal muscle. Centrally located nuclei and has intrinsic myogenic activity
What is used to measure lung function and what are tidal volume, inspiratory capacity and FVC, inspiratory reserve volume, expiratory reserve capacity and residual volume?
Spirometry. Tidal volume - volume of air moved in and out of lungs at rest. Inspiratory capacity and FVC - max volume of air in or out of lungs in a single respiratory cycle. Inspiratory reserve volume - volume of air you can draw into lungs. Expiratory reserve capacity - volume of air you can expel from lungs. Residual volume - volume of air that remains in lungs after maximal exhalation
Where is the splenic artery, what is the function of the spleen and what can blunt trauma to the abdomen do to the spleen?
Splenic artery found in left hypochondrium (deep to 9th-11th ribs). Spleen has function in lymphocyte proliferation and RBC filtration, storage and destruction. Blunt abdominal trauma can sheer spleen away from splenic artery to cause haemorrhage
Describe the luminal phase of carbohydrate digestion
Split into shorter molecules by salivary and pancreatic enzymes to form disaccharides and limit dextrins
What are the divisions of the superior laryngeal nerve, what do they each do and what is the function of the recurrent laryngeal nerve?
Splits into internal (sensory and autonomic to larynx above vocal cords) and external (motor to cricothyroid) laryngeal nerves. Recurrent laryngeal is motor to all other intrinsic muscles and sensory to larynx below vocal cords
What does the internal iliac split into, what division is each artery in, where does the obturator artery pass and what does its branch supply?
Splits into superior (anterior division) and inferior (posterior division) gluteal arteries and obturator artery (anterior division) which passes through obturator foramen. Acetabular branch supplies hip joint
What are the types of mutations and what can cause them?
Spontaneous mutations - errors in replication and base modifications. Induced - environmental such as radiation, chemicals and infectious agents.
How do IFNs have anti-viral properties?
Spread to local cells and induce resistant state, MHC expression and NK activation
What is the function of the collateral ligaments of the knee and describe the structure of each
Stabilise the hinge-like movement of the knee Lateral collateral ligament - thick, strong ligament connecting femur to fibula Medial collateral ligament - thickening of articular capsule attached to medial malleolus
What happens in contractile cell action potential?
Starts with Na+ influx, then prolonged depolarisation/plateau phase due to Ca2+ entry (L type Ca2+ channels) that helps muscle contract for longer. K+ VGCs then open to repolarise cell
What are statins and how do they work?
Statins inhibit HMG CoA reductase so inhibit cholesterol synthesis so feedback mechanism increases cholesterol uptake from blood
Where do microbes go after contact/entry and how?
Stay on skin (HPV, athletes foot), local spread due to enzyme production (hyaluronidase, peptidase) that breaks down cell-cell connections and gain access to bloodstream or lymphatics but are exposed to immune system
What movement happens during inspiration/expiration?
Sternum and ribs are raised during inspiration (increases volume so decreases pressure) and are lowered during expiration
How can ligands activate inhibited proteins?
Steroids can diffuse through membrane. Ligand binds to receptor and causes ligand-binding domain of receptor to shut and dissociation of inhibitory proteins
How do bacteria adhere and gain entry?
Stick to mucosal cells via non-specific mechanisms. Pili (conjugation) and fimbriae (interact with cell surface receptors) also help. Haemagluttinin provides specific adherence.
What are cholinesterase inhibitors?
Stimulate GI function, cognitive enhancers and stimulate skeletal muscle activity. Neostigmine for myasthenia gravis
What stimulates the RAAS and describe the mechanism of the RAAS
Stimulated by symmpathetic nerve activation (beta receptors), renal artery hypotension or decreased Na delivery to DCT. Activation of JG cells --> renin release --> angiotensinogen coverted into angiotensin I --> angiotensin I converted to angiotensin II in lungs by ACE --> stimulates aldosterone production and ADH release, arteriolar constriction and increased Na reabsorption in PCT
What does stomach distension cause and what are the receptors on parietal cells?
Stomach distension causes stimulation of vagal nerve and ENS. MACHRs on parietal cells and ECL cells (detect ACH released by PNS), histamine H2 receptors (detect histamine released from ECL cells) and CCK2/gastrin receptors on parietal and ECL cells (detect gastrin from G cells which detect digested protein and AAs to boost acid production by increasing histamine release)
What is the type of mucosa found in stomach, what does it produce and what is it covered by?
Stomach has glandular mucosa that produces gastric juice that helps reduce contents to chyme. Mucosa is covered in a thick protective layer of mucous
What does the stomach secrete, what is released by parietal cells and what is pepsinogen?
Stomach secretes HCL, intrinsic factor, pepsinogen, chymosin (coagulates milk protein), mucus and lipase. Parietal cells secrete HCL and intrinsic factor. Pepsinogen activated by HCL --> pepsin that digests protein
What happens during termination?
Stop codon causes binding of release factors to A site and allows release of protein and break-down of ribosome
What is the function of the sER?
Stores Ca, detoxification of absorbed drugs/toxins and synthesis of lipids and carbohydrates
What diseases are associated with high TAG levels, when is dyslipidaemia common and how do smoking and diabetes cause atherosclerosis?
Stroke, CHD and atherosclerosis. Dyslipidaemia common in diabetics. Smoking and diabetes cause formation of oxidised LDL (free radicals) that binds to scavenger receptors on macrophages rather than LDL receptors so macrophages become lipid laden and form foam cells --> formation of fatty streaks --> plaque formation
What is the function of the IVDs and what are the annulus fibrosus and nucleus pulposus made from?
Strong attachment between vertebral bodies designed for weight bearing and strength Annulus - 15-20 collagenous laminae running obliquely Pulposus - type II collagen, H2O, proteoglycans
What is the structure and function of the middle ear?
Structure - ossicles (malleus, incus and stapes that tranmit sound mechanically by vibration) and tympanic membrane Function - impedance matching, pressure equalisation and inner ear stimulation
What is the structure and function of the inner ear?
Structure - oval window (connects with middle ear), cochlea and semi-circular canals Function - sound filtering and signal transduction using mechanical, hydrodynamic and electrochemical signals
What is the structure and function of the outer ear?
Structure - pinna, concha and auditory canal Function - protects, localises and amplifies using air vibration
What are the arteries that supply the upper limb?
Subclavian --> axillary --> brachial (medial) --> radial/ulnar --> palmar arch --> digitial branches
What does the spinocerebellar tract transmit and what is the pathway that its neurons take?
Subconscious propriception from spinal cord to cerebellum. 1y sensory neuron synapses with 2y neuron in dorsal horn and 2y neuron enters ipsilateral tract to ascend to cerebellum
What are bronchopulmonary segments?
Subdivisions of lung lobes so diseased segments can be removed surgically
What structures allow for linkage of CNS to peripheral blood flow for thirst mechanism and what can destruction of these areas cause?
Subfornicular organ and organum vasculosum of the lamina terminalis (OVLT) allows linkage of CNS to peripheral blood flow as they have extensive vasculature and lack a normal BBB. Destruction of these parts of hypothalamus can cause partial/total loss of desire to drink
What structures are found in the submandibular, muscular and submental triangles?
Submandibular - submandibular gland, CN XII, parts of facial artery and vein Muscular - infrahyoid muscles (sternohyoid, thyrohyoid and sternothyroid), thyroid and parathyroid glands Submental - floor of mouth and contains mylohyoid
What divides the subphrenic recess and what are the parts of the subhepatic recess?
Subphrenic recess divided into L + R by falciform ligament. Subehapatic recess has pouch of Morrison on R and lesser sac on L
What are the boundaries of the mediastinum and what are some features?
Superior border - thoracic inlet (T1), inferior border - diaphragm, anterior border - sternum and costal cartilage, posterior border - thoracic vertebrae. Highly mobile and contains hollow air or fluid-filled structures
What are the superior, lateral and inferior borders of the oral cavity?
Superior border is hard (made from maxilla and palatine bones, anterior) and soft (muscular, posterior) palates. Lateral borders from mandible posteriorly and buccal muscles anteriorly. Inferior border is muscular with scaffolding from mandible
How can you test the superior/inferior recti muscles and superior/inferior oblique muscles
Superior rectus - abduct eye and elevate Inferior rectus - abduct eye and depress Superior oblique - adduct eye and depress Inferior oblique - adduct eye and elevate
Where are teeth embedded and what are they innervated by?
Superior teeth are embedded in maxilla (innervated by superior alveolar nerve from V2) and inferior teeth are embedded in mandible (innervated by inferior alveolar nerve from V3 that runs through mandibular foramen then emerges through mental foramen).
What artery supplies Broca's and Wernicke's areas and what does a stroke of the proximal part of this artery cause?
Supplied by MCA so stroke of proximal part causes global aphasia
What does the anterior tibial supply, what is dorsalis pedis, what does it supply, what branches does it give off, where is it found, what does the posterior tibial supply and where is it found?
Supplies dorsiflexors and extensors of ankle and foot. Dorsalis pedis (found lateral to tendon extensor hallucis longus) is continuation of anterior tibial and supplies dorsum of foot and gives off branches to arcuate artery. Posterior tibial supplies plantarflexors and lateral muscles and found between medial malleolus and calcaneal tendon
What are the functions of the suprahyoid, infrahyoid muscles and extrinsic muscles?
Suprahyoid (mylohyoid, digastric and stylohyoid) - provide base for tongue and elevate hyoid and larynx for swallowing and tone production Infrahyoid (sternohyoid, thyrohyoid, sternothyroid and omohyoid) - depress hyoid and larynx during swallowing and speaking Extrinsic - move larynx as a whole
What hypothalamic nuclei affect the posterior pituitary and how?
Supraoptic and paraventricular nuclei axons project to posterior pituitary via pituitary stalk. Release peptides into capillaries to circulate in blood. Several other nuclei have shorter axons that release peptides onto capillary plexus in neck of pituitary stalk
What is the function of surface mucus cells, what does the mucus do and how can it be disrupted?
Surface mucus cells secrete mucous (forms a protective layer and prevents interaction between cells and acid) and bicarbonate (neutralises stomach acid). Can be disrupted by stress/chemicals/alcohol/NSAIDs
What are the surgical treatments for GORD?
Surgically treated by fundoplication which tightens and reinforces LOS by wrapping fundus of stomach around outside of LOS
What receptors are found on a T cell and how do they kill infected cells?
TCRab and CD8 co-receptors. Kill cells repeatedly by apoptosis
What layers surround the spinal cord, what is the epidural space, what contains CSF and what do layers/sections do lumbar punctures and epidural anaesthesia involve?
Surrounded by dura mater (not connected to vertebrae) which has large epidural space (fat-filled space through which all spinal nerves run), arachnoid mater and pia mater (CSF found in subarachnoid space). LP involves subarachnoid space and epidural involves epidural space
What surrounds axons, what does it do and what cells is this produced by?
Surrounded with myelin sheath that insulates the nerve and increases conduction. Produced by Schwann cells in PNS (1 Schwann cells for each axon) and oligodendrocytes in CNS (1 oligodendrocyte for many axons)
What structures are found within the carotid sheath, what structures escape it, and what structures run outside of it?
Surrounds common and internal carotids, IJV and CN X CN IX, superior laryngeal nerve, spinal root of CN XI and CN XII escape the upper sheath Ansa cervicalis runs outside over IJV Ascending sympathetic fibres run outside using internal carotid for support
What are susceptible, resistant and permissive cells?
Susceptible - cells that have receptor for virus. Resistant - cells that don't have virus receptor. Permissive - can replicate virus
What are the differences between sympathetic and parasympathetic nervous system and what are the names for each?
Sympathetic (thoracolumbar) uses NE with longer postganglionic, parasympathetic (craniosacral) uses ACH with longer preganglionic
How is sympathetic different to parasympathetic?
Sympathetic/thoracolumbar uses nerves and hormones (adrenaline) but parasympathetic only uses nerves
What are symptoms and signs of anaemia?
Symptoms - SOB, feeling faint, tiredness, worsening of heart related pain, palpitations. Signs - pale, tachycardia, bounding pulse, systolic flow murmur, cardiac failure and retinal haemorrhage
What are the symptoms and signs of HF and what causes these?
Symptoms - breathlessness, ankle swelling and fatigue. Signs - raised JVP, pulmonary crackles and peripheral oedema). Caused by cardiac abnormality and decreased CO
Where do nociceptors synapse, where do their axons decussate and travel, what does this tract transmit and what are its components?
Synapse in lamina I or II of dorsal horn. Axons decussate in spinal cord and project up contralateral spinal cord in spinothalamic tract which transmits pain, temperature (both lateral part) and crude touch (anterior part)
Where do sinus afferents synapse, where does the NTS project to and what does this area do via which routes?
Synapse in nucleus of the solitary tract (NTS) of lower medulla. NTS projects ventrally to vasomotor centre that activates vagal parasympathetic outflow via nucleus ambiggus or sympathetic outflow via reticulospinal tract
Where does synovial fluid seep into and what are the functions of synovial fluid?
Synovial fluid seeps into non-loaded articular cartilage Reduces friction between articular surfaces, distributes force across joint surface, forms a reserve volume and nourishes the articular cartilage
What are vertebral facet joints and what are their characteristics in cervical/thoracic/lumbar regions?
Synovial plane joints between inferior and superior articular processes Cervical - quite shallow Thoracic - quite steep Lumbar - nearly vertical (most interlocking) Subluxation therefore most common in cervical region
What histological features are seen in coeliac disease?
T lymphocyte infiltration of epithelium, partial/total atrophy of intestinal villi and crypt hyperplasia/increased mitotic activity
What are the two types of MRI scan?
T1 (normal anatomy) and T2 weighted (pathology, sensitive to H2O content so good for inflammation/oedema) T1 - CSF appears dark, yellow bone marrow is white T2 - CSF and water/oedema appear white
What are the types of MR imaging and how do they differ?
T1 - black CSF T2 - white CSF so sensitive to pathoology (tumour, inflammation, infection and ischaemia)
What vertebral levels are sympathetic, what are the different ganglia and why does it have generalised effects?
T1-L2. Preganglionic fibres synapse in paravertebral (T1-T4 ), prevertebral (T5-L2 and pass through synpathetic chain) and adrenal medulla. Has generalised effects as 1:30 preganglionic : sympathetic postganglionic neuron ratio
How do thyroid hormones impact release of anterior pituitary hormones and what is the timing of the release of some of them?
T3/T4 inhibit TRH and TSH release FSH and LH are released monthly in females GH released at night in both sexes TSH released during the day in both sexes
How and why are TAGs packaged and how are dietary TAGs and liver-derived TAGs packaged?
TAGs are packaged because they are hydrophobic and are packaged into lipoproteins using cholesterol and apoproteins. Dietary TAGs packaged in chylomicrons and liver-derived TAGs packaged in VLDLs
What are TAGs broken down into and what are the products used for?
TAGs broken down --> FAs and glycerol. FAs --> acetyl CoA and used for cholesterol synthesis and respiration Glycerol --> glucose for gluconeogenesis
What does TCA cycle combine, what does it produce and what reactions are irreversible?
TCA combines acetyl CoA and oxaloacetate to form citrate. Produces CO2, 3NADH and FADH and some energy in GTP via substrate level phosphorylation. Reactions that lose CO2 are irreversible
What are the stages of swallowing?
Tongue pushes bolus to oesophagus --> soft palate contracts to prevent entry into nasal cavity --> larynx elevates and epiglottis flattens to close larynx --> oesophagus contracts to push bolus down oesophagus
What is tonic and phasic activity?
Tonic is always active and level of activity determines which is predominant (saliva or tear production). Phasic activity only needed at certain times so becomes active to take control (sexual activity, urination and pancreatic secretion)
What is the structure of a sarcomere?
Thick (myosin) and thin (actin) filaments that interact (myosin pulls actin) with myosin heads sticking out Accessory molecules - tropomyosin (blocks myosin binding site) and troponin (binds Ca) Myosin held in place by M line, actin embedded in Z line, A band where myosin, I band where no myosin, H zone distance between actins in centre
What is scissor/spastic gait?
Thigh swings across body during swing so causes difficulty in putting heel on ground so unstable toe walking. Unilateral (stroke or cerebral palsy) or bilateral (cerebral palsy)
What is the cortex and how is it arranged?
Thin outer layer of grey matter arranged in sulci (dips) and gyri (ridges).
What are mutagens?
Things that cause mutations in genes. Physical - UV, radiation and heat, chemical - nicotine, pesticides and methane, biological - bacteria and viruses
What nerve innervates posterior leg compartment, what movement does this allow, what is its blood supply and where do posterior compartment muscles insert?
Tibial division of sciatic nerve innervates posterior leg compartment which allows plantarflexion and digit flexion. Blood supply from posterior tibial artery and posterior compartment muscles insert onto calcaneal tendon
What are the types of junctions?
Tight - prevent passage of molecules, adherens - tether cells together, gap - allow passage of small molecules, desmosomal - hold epithelial cells together, hemidesmosomal - hold epithelium to BM
How is slow pain generated?
Tissue damage releases pro-inflammatory chemicals into ECF. Inflammation opens TTX resistant Na channels (in free nerve endings) --> continuous depolarisation of ending --> tonic generation of APs
Why is the nose well vascularised and what are the arteries found on the anteroinferior septal wall?
To allow for humidification and warming of inspired air. Septal branch of sphenopalatine and labial arteries, greater palatine and anterior ethmoidal
Why is work of breathing necessary and how does COPD affect this?
To overcome elastic recoil and resistance to airflow. COPD increases resistance to airflow so work of breathing increases, but increased O2 consumed by respiratory muscles
What is transamination, what does it require, what keto acid do alanine, glutamate and aspartate use and why are these 3 AAs glucogenic?
Transamination is the conversion of one AA to another using keto acids. Requires vitamin B6. Alanine uses pyruvate, glutamate uses a-ketoglutarate and aspartate uses oxaloacetate. These 3 AAs are glucogenic as they form a TCA cycle intermediate or pyruvate
What is transamination and what enzymes are measured in liver tests to show hepatocyte damage?
Transfer of amino group to a keto-acid to form a different AA. Alanine and aspartate aminotransferases are measured in liver tests
What is a TIA?
Transient episode of neurologic dysfunction caused by ischaemia without acute infarction
Describe zika transmission, symptoms and control
Transmission - mosquito vector, semen, urine, saliva, blood and breast milk. Symptoms - microcephaly, fever, rash, headache and conjunctivitis. Controlled using insecticides
Describe influenza transmission symptoms, structure, types and new strains?
Transmission - via droplets, indirect and direct contact. Symptoms - fever, nausea, tiredness, aches. Structure - ss(-) RNA with envelope and HA/NA surface spikes. Types - A (humans, animals and birds), B (humans) and C (humans). New strains from minor changes in antigenic character.
What does the corticospinal tract transmit and what is the pathway that its neurons take?
Transmits motor signals from cortex to spinal cord UMN has cell body in 1y motor cortex and axon travels through internal capsule to brainstem. Tract decussates in inferior medulla and UMN enters ventral horn and synapses with LMN which leaves ventral horn
How is ebola transmitted and what are the symptoms on each day?
Transmitted through bodily fluids and blood. Symptoms appear days 7-9. Day 10 - high fever and vomiting blood. Day 11 - bruising, brain damage, bleeding from orifices. Day 12 - internal bleeding, LOC, seizures, death
How is the weight of the upper body transmitted and what is the significance of the angle of the femurs?
Transmitted through vertebral column then through ilium into femurs Femur angle re-centres support directly under the body to make bipedal standing more efficient
What are the functions of the cardiovascular system?
Transport of O2 and nutrients and removal of waste products. Also provides immune protection
What is coupled transport?
Transport of solute is coupled with co-transported ion (moved by ATP). Releases free energy as co-transported ion moves down conc gradient so drives solute against conc gradient. Symport if same direction, antiport if opposite
How is glucose transported across the membrane and what are the different GLUT transporters?
Transported across membrane using GLUT transporters. GLUT1 is constitutive glucose transporter (low Km so active at low concentration), GLUT2 in for uptake in liver/pancreas (high Km) and GLUT4 in muscle and adipose tissue (low Km)
What divides the peritoneal cavity into supracolic and infracolic compartments and what are found on the lateral sides of the ascending/descending colon and what can happen to these during infection?
Transverse mesocolon divides into supra/infracolic compartments. Lateral sides have paracolic gutters through which infection/fluid can spread
What muscle is found in the posterior arm comparment, what is its role, where does the long head attach, where does it insert and what is the motor innervation?
Triceps brachii is an elbow extensor and long head is shoulder extensor. Long head attaches to infraglenoid tubercle of scapula and muscle inserts onto tendon that attaches to olecrannon process. Receives motor innervation from radial nerve
Describe the structure of the RV
Tricuspid valve connected to papillary muscles via chordae tendineae and closes on contraction. Moderator band of muscle allows simultaneous contraction. Trabeculae carnae forms rough walls
What is the function of the trigeminal nerve and what are the divisions?
Trigeminal nerve provides sensory innervation to entire face. Has opthalmic (V1), maxillary (V2) and mandibular (V3) divisions
What is Down syndrome?
Trisomy 21, 1 in 700 births. Distinct facial features, muscle hypotonia, single palmar crease, congenital heart defects, IQ usually <50. More common with increase in maternal age
What are anaplastic tumours?
Tumours that are poorly differentiated so have a worse prognosis and difficult to determine site of origin. Loss of polarity and orientation causes disordered growth
What is Weber's test?
Tuning fork placed in middle of forehead and which ear tone is heard Conduction deafness - sound louder in affected ear (vibrations reach cochlea by air and bone but are out of sync so interfere with each other in more sensitive ear) Sensorineural deafness - sound louder in unaffected ear
What are the two types of personality and which has a higher hypertension risk?
Type A (lives with higher stress levels so higher risk) and type B (lives with lower stress levels so less risk)
What are type I and type II diabetes and what is the normal fasting glucose?
Type I diabetes - disruption of insulin secreting cells so reduced insulin production Type II diabetes - cells don't respond properly to insulin and not enough secreted to compensate Normal fasting glucose - 3.5-5.5mmol/L
What are the types of hypersensitiity and what microbes cause each?
Type II (M. pneumonia) - antibodies against RBCs cause lysis and haemolytic anaemia. Type III (S. pyogenes) - inadequate clearance of antigen-body complex so inflammation (eg. glomerulonephritis). Type IV (M. tuberculosis) - granuloma formation
What type of cell makes surfactant, what are the different types and what does a lack of surfactant cause?
Type II pneumocytes. Made from lipoprotein A+D (coat bacteria and viruses and help immune system) or B+C (reduce surface tension and ensure proper lung function). Lack of surfactant can cause IRDS in neonates or cause very strenous inspiratory efforts to overcome high surface tension
What are isoenzymes?
Types of enzymes that catalyse same reaction in different tissues and have different kinetic properties (Km and Vmax). Lactate dehydrogenase has 5 forms (heart, muscle and tetramer functional enzyme)
What is a typical small intestine presentation and common small intestine problems?
Typical presentation - diarrhoea, weight loss, nutritional deficiencies, abdominal pain/discomfort. Common problems - coeliac disease or IBS (Crohn's and UC)
Where are UMN tracts found in the spinal cord and what are UMNs involved with?
UMN tracts found in ventral and lateral parts of spinal cord. UMNs involved with muscle excitation, muscle inhibition, efference copy, reflex modulation and activation of other brainstem UMNs
What are the upper and lower oesophageal sphincters and what are the 3 oesophageal constrictions?
UOS is anatomical sphincter produced by cricopharyngeus. LOS is physiological sphincter aided by acute angle of oesophagus and 'pinch-cock' effect of diaphragm. There are cervical, thoracic and diaphragmatic oesophageal constrictions
How do the ulnar, musculocutaneous and median nerves run through the arm and what motor and sensory innervation does the musculocutaneous nerve give?
Ulnar - anterior compartment of arm then pierces intermuscular septum at elbow to run posteriorly to medial epicondyle to enter forearm Musculocutaneous - runs in posterior compartment of arm and supplies motor innervation to posterior arm and sensory innervation to lateral forearm (lateral cutaneous nerve) Median nerve - runs in anterior compartment of arm (with brachial artery) then crosses anterior aspect of elbow to enter anterior forearm compartment
Where is ulnar nerve most commonly injured, what does this cause and what does this do to hand muscles?
Ulnar nerve most commonly injured at medial epicondyle of humerus. Causes clawhand and muscle atrophy of intrinsic muscles (most obvious in 1st dorsal intraosseous web)
What are the methods of vesicle recycling and why is this important?
Ultrafast, kiss-and-run, clathrin mediated and important so no net increase in membrane surface area
What is IBD, where does CD affect, what are symptoms, what can it lead to and how is it diagnosed?
Umbrella term that refers to chronic inflammation of lower GIT. CD affects whole GIT but mainly localised to small bowel. Symptoms - diarrhoea, abdo pain, fatigue, fever and weight loss. Leads to changes in bowel epithelium, bowel obstruction from scarring, ulcers and fistulas. DIagnosed by faecal calprotectin and colonoscopy.
What is the organisation of dermatomes over the upper and lower limbs?
Upper - anticlockwise over shoulder from C4 Lower - down anterior aspect then back up posterior aspect (L1-S3)
What are common upper and lower GI symptoms?
Upper GI symptoms - acid reflux, vomiting, belching, gastroparesis and bloating Lower GI symptoms - diarrhoea, abdominal pain, constipation and bloating
What do the upper and lower airway contain?
Upper airway contains nasal and oral cavities, nostrils and pharynx and larynx. Lower airway contains trachea, bronchi and lungs
What epithelium lines upper airways and lower airway and alveoli and where is mucus found and what is its function?
Upper airway has ciliated pseudostratified columnar epithelium and lower airway has simple squamous epithlium. Alveoli has single layer of thin epithelium for gas exchange. Mucus found everywhere apart from alveoli to trap dust and bacteria that are moved by cilia
How does a central cord injury present?
Upper and lower limb weakness (upper limb more severe) with sensory loss below injury level but motor function more severely impaired
What are absorbed in upper ileum and terminal ileum and where is vitamin B12 stored?
Upper ileum - B12 and bile acids. Terminal ileum - most Fe, protein, fats, CHO and folate. B12 is stored in the liver
How does TNF cause leukocyte extravasation?
Upregulates adhesion molecules and makes endothelium stickier. IL-8 chemokine then activates adhesion molecules to increase binding and arrest
What are B cells and what do they do?
Use immunoglobulins as BCRs and recognise antigen without other cells. Activated B cells differentiate into plasma cells that secrete Ig with specificity identical to BCR
What NTs do RF modulatory systems use and what are their outputs?
Use monoamines and ACH with outputs to cortex, hypothalamus, limbic system and descending projections
What is PCR?
Used to increase amount of DNA. Heat to 95 to denature DNA, heat to 55 to allow binding of oligonucleotide primers, then 75 for tac-polymerase for replication
Describe the virus life cycle
Virus entry --> uncoating --> genome replication --> protein synthesis --> virus assembly and maturation --> virus release
What are the types of contrast media and how do they work?
Used to show differences in densities of organs by increasing average atomic number of hollow structure. Iodine (for imaging cardiovascular system), gadolinium (for MRI) and barium sulfate (for imaging GI tract). Air or gas also used and gives negative contrast
What happens to VLDL after secretion from the liver?
VLDL secreted from liver --> acquires cholesterol and apoC / apoE from HDL --> hydrolysis by LPL (activated by apoC) yields VLDL remnants called IDL --> hepatic TAG lipase transforms IDL into cholesterol-rich LDL (loses apoC and apoE so remains in circulation for longer and taken up by liver and peripheral tissues)
What is the vestibulo-ocular reflex, what are the afferent and efferent and how is this tested?
VOR where eyes rotate in opposite direction to head to keep direction of gaze constant and keep the object in view. Afferent is CN VIII and efferent is CN VI and CN III. Tested by holding pts eyes open and gently rotating head from side to side (eyes should rotate in head to keep gaze direction constant)
What signs does a vagus nerve and hypoglossal nerve lesion cause?
Vagus nerve lesion - uvula deviation away from lesion Hypoglossal nerve lesion - tongue deviation towards lesion
What are varicosities and what do they do?
Varicosities on end of postganglionic axon secrete NT into space surrounding muscle.
What is the countercurrent exchange mechanism in the kidney?
Vasa recta provides countercurrent exchange by providing blood and oxygen supply to kidney but preventing washout of the highly concentrated solutes in the medulla
What increases capillary permeability and how does this cause oedema?
Vascular damage from trauma, burns or inflammation so allows water to flow more freely and allows passage of proteins to reduce oncotic pressure difference
How do tumours metastasise?
Vascularisation of tumour --> cells detach --> BM degraded --> tumour cells circulate in blood --> some cells adhere to vessel walls --> extravasation and migration to local tissue --> 2y tumour forms. Occurs through haematogenous or lymphatic dissemination
What is 1st pass metabolism and what administration avoids this?
Venous drainage of gut, small/large intestine pass into portal vein into liver where drug metabolised by cytochrome P450. Nasal, sublingual and IV drugs transported via veins so pass around body before liver
What controls venous return?
Venous return controlled by respiratory pump, one-way valves, muscular pump and venoconstriction
What is the function of the ventral and dorsal cochlea nuclei?
Ventral - fast and precise and projects to olivary nucleus to encode intensity/timing of noise Dorsal - complex responses and projects to lateral lemniscus and encodes quality of sound
What are the two parts of the dopamine system and what do they control?
Ventral tegmental area (VTA) - organising behaviour, focusing/attention and reward/motivation Substantia nigra - initiation/switching of movement
Why are atria not essential at rest and why does this mean AF is often detected during exercise?
Ventricular elastic recoil enough to suck in blood from atria. Detected during exercise as contraction necessary to fill ventricles as diastole shortens
What is the posterior circulation to the brain?
Vertebral - supplies spinal cord and dorsal medulla of brainstem via PICA Basilar - supplies pons and cerebellum PCA - Supplies inferior and medial aspects of temporal and occipital cortex, thalamus and posterior internal capsule and midbrain and anastomoses with MCA
Describe the anatomy of a typical vertebra
Vertebral body on anterior part to give strength and support weight Vertebral arch formed by pedicles meeting lamina and forming vertebral foramen for spinal cord 1 spinous and 2 transverse processes for muscle attachment and 4 articular processes (superior and inferior) that articulate with above/below vertebrae
What is Rinne's test?
Vibrating tuning fork held in air then on mastoid process Conduction deafness - bone conduction better on affected side Sensorineural deafness - air conduction better in affected ear and sound loudest in unaffected ear
How do T cells recognise virally infected cells?
Virus infects cell, injects DNA/RNA and produces viral proteins that are presented on MHC-I. TCRab binds to MHC-I and causes apoptosis
What are the different types of motor nuclei of CNs?
Visceral motor - pre-ganglionic parasympathetic fibres Somatic motor - project to skeletal muscle Branchial motor - project to muscles derived from branchial arches (craniofacial structures)
What are the main functions of the RF?
Visceral regulation via control of ANS, maintenance of consciousness/sleep/arousal, sensory/motor filtering and modulation and somatic reflex regulation and premotor control
Where is EJV visible with normal venous range, what causes increased EJV prominence and what does EJV prominence give an estimate of?
Visible above clavicle for short distance (<4cm above sternal angle). Raised EJV prominence indicates raised venous pressure caused by heart failure, SVC obstruction, enlarged supraclavicular lymph nodes or raised intra-thoracic pressure. EJV prominence gives estimate of right atrial pressure (nearly equal to CVP)
Where is vitamin B3 absorbed, what does it form, how can it be made and what can deficiency cause?
Vitamin B3/niacin absorbed in jejunum and forms NADP and NAD. Can also be made from tryptophan. Causes early pellagra - loss of appetite, irritability, abdo pain, vomiting. Then late pellagra - 4D's )dermatitis, diarrhoea, dementia and death
What are the causes of vitamin deficiency?
Vitamin deficiency caused by decreased intake (alcohol dependency, vegans, elderly with poor diet and anorexic patients) or decreased absorption (malabsorptive state, ileal disease/resection, liver and biliary tract disease, bacterial overgrowth and oral antibiotics)
What are vitamins and heme?
Vitamins are micro-nutrients that body can't synthesise that are needed to synthesise co-enzymes and co-factors. Heme is a co-factor with porphyrin ring containing iron needed for enzyme activity in oxidation reactions (eg. Cyt C oxidase)
Where are vocal ligaments found and what are the different vocal cords?
Vocal ligaments on superior border of cricothyroid ligament. Vestibular (false vocal cords) and vocal (true vocal cords) folds. Rima glottidis is space between true cords
What controls language vocalisation and language perception, what are symptoms of Broca's and Wernicke's aphasia?
Vocalisation - Broca's area Perception - Wernicke's area (upper end of superior temporal gyrus in temporal lobe) Broca's aphasia - halting speech, repetitive, disordered grammar/syntax/word order Wernicke's aphasia - fluent speech, no repetition, good syntax, ok grammar, meaningless, inappropriate words
What is Von Gierke's disease, what do fasting children with this disorder have and how is it treated?
Von Gierke's disease is a deficiency in glucose-6-phosophatase (converts G-6-P --> glucose) so prevents liver making glycogen stores accessible to the rest of the body and also gluconeogenesis from glucogenic AAs and lactate. Fasting children have hypoglycaemia, hepatomegaly and lactic acidosis. Treated by providing starch several times per day to provide slow-release sugar
What is the Warburg effect in cancer cells and how do cancer cells have enough substrates for TCA?
Warburg effect is upregulation of glycolytic pathways due to HIF release even if O2 is present. Cancer cells top-up a-ketoglutarate in TCA using glutamate and glutamine
What is water and osmotic diuresis?
Water diuresis - overhydration dilutes blood so ADH release inhibited to create a large volume of dilute urine (diabetes insipidus). Osmotic diuresis - excess sugars (glucose) provide osmotic force to pull water into urine to create a large volume of sugary urine (diabetes mellitus)
What are the sources of water gain and loss?
Water gain - food, fluids and metabolic processes Water loss - urine, faeces, sweat, insensible losses
How does a compensatory method of controlling low BP stimulate the RAAS and reverse this effect?
Water moves into lumen from ISF and dilutes blood to cause hyponatremia which is detected by macula densa. This stimulates renin release from JG which increases BP, forcing water back into ISF
What substance moves out of the lumen in the descending and ascending loops of Henle and how?
Water moves through aquaporins in descending limb and Na/Cl move through thick portion of ascending limb through NKCC2
Where are different drugs absorbed and why?
Weak acid drugs absorbed in stomach as low pH causes eqm shift to protonated which is lipophilic, weak base drugs in small intestine as unprotonated in alkaline solution
What is somatotopic organisation?
Where specific part of body is associated with distinct location in CNS
What makes up white and grey matter and what is a collection of cell bodies called in CNS and PNS?
White matter made from myelinated axons and grey matter made from unmyelinated components (cell bodies and synapses). Collection of cell bodies is nucleus in CNS or ganglion in PNS
What are flexion reflexes?
Withdrawal from painful stimulus mediated by nociceptor afferents that act on spinal cord interneurons. Are polysynaptic so can be suppressed by brain
What is the pathway of generating and expressing speech and what does lack of feedback of own heard speech cause?
Word concepts are formed in Wernicke's area and stored in a buffer memory then sent via arcuate fasciculus to Broca's area Without feedback of own heard speech, learning to speak is difficult/impossible
How do b-lactams work and examples?
Work by inhibiting transpeptidase so cross-links in cell wall can't form and bacteria (Gram +ve) susceptible to lysis. Penicillins and cephalosporins
What are inverse agonists?
Work on receptors already active without ligand bound. Act on unoccupied receptors to produce opposite effect of agonist/below baseline
Where does common peroneal nerve run, what does it split into, what innervates anterior and lateral leg compartments, what movements do each of them do and what sensory innervation to superficial and deep peroneal nerves give?
Wraps around head of fibula and splits into deep (anterior compartment) and superficial (lateral compartment) branches. Anterior compartment dorsiflexes and extends digits and lateral compartment everts Deep peroneal gives sensory innervation to foot dorsum and superficial peroneal gives sensory innervation to big and 2nd toe
What is a clinical symptom of radial nerve damage, what can cause temporary symptoms and what causes radial nerve palsies in neonates?
Wrist drop is a clinical symptom due to paralysed wrist/finger extensors and unopposed action of FDS/FDP. Temporary symptoms also caused by radial nerve compression/stretch due to falling asleep with arm hanging. Radial nerve palsies in neonates 2y to compression on inferior arm by pelvic brim
Where do the wrist flexors and extensors originate and what nerve innervates each?
Wrist flexors (ulnar nerve) originate at medial epicondyle of humerus and wrist extensors (radial nerve) originate at lateral epicondyle of humerus
Describe the shape and position of the cruciate ligaments and what do they prevent?
X-shaped ligaments running from intercondylar region of tibia to femur. Prevent anterior/posterior movement of the tibia relative to the femur
What is X inactivation and how does it occur?
Xist (long non-coding RNA in XIC) leads to chromatin changes. Spreads along surface of X chromosome until pseudoautosomal region and inactivates chromosome. Forms Barr bodies on edge of nucleus
What is Zollinger-Ellison syndrome (ZES) and what can it cause?
ZES is an ectopic secretion of gastrin by neuroendocrine tumours --> gastric acid hypersecretion --> severe gastroesophageal peptic ulcer disease