Y2 Neuroscience
which receptor carries most of the fast voltage changes on postsynaptic CNS neurons, AMPAR or NMDAR?
AMPAR (NMDAR only opens after depolarisation has begun)
which system is also known as the 'vegetive' system
ANS
which genes are linked to alzheimers
APP (amyloid precursor protein, chromosome 21), presilin 1 and 2 (chr 14), and Apolipoprotein ε4 allele (chr19)
anterior spinal artery syndrome
ASA becomes occluded, damaging ventral portion of spinal cord at that level - eg patient has fine touch/proprioception *without pain + temp*
3 types of MS plaques
Acute (full of inflammatory cells), remyelinating (months after the acute T cell attack), burnt out (remyelination ceased)
what is ARMD
Age-related macular degeneration. painless loss of vision in the center of the visual field (the macula) because of drusen/damage to the retina.
outward current VS inward current
An inward current is the result of an influx of positive ions (usually Na+, Ca2+) or an efflux of negative ions. An outward current is the result of an influx of negative ions (usually Cl-) or an efflux of positive ions (usually K+)
which part of the brain especially seems to be able to regulate the emotional variability of pain?
Anterior cingulate cortex (ACC)
name 2 spinothalamic syndromes
Anterior spinal artery syndrome: artherosclerosis ors pinalinjury. Syringomyelia: occlusion of crossing pathways by degenerative expansion of the spinal central canal *both deficits in pain + temp sensation*
which adrenoceptors are present in blood vessels?
B2 (dilation), a1 (constrict), a2 (constrict/dilate)
what role does the basilar membrane play in hearing complex sounds?
BM is tuned along its length for sound frequency (membrane is widest at apex = lowest sound). it splits complex sounds into their constituent components.
which factors change during 'fight or flight response' to danger
BP↑ Heart Rate ↑ Pupils dilate. Blood supply to Skeletal Muscle in the limbs ↑ Blood supply to skin, kidney, digestive tract ↓ Respiration ↑ Blood Glucose ↑
which is more common, Central Vein Retinal Occlusion or BRVO?
BRVO is 3 times more common
who coined the term long term potentiation?
Bliss and Lomo - first to demonstrate Hebb's ideas in living tissue
what are the most common type of sensory axons?
C fibres
elbow flexion/supination reflex has which nerve roots?
C5,C6
after arising in the root of the neck, the vertebral arteries pass into the transverse foramen of which vertebra?
C6 (it skips C7)
elbow extension reflex has which nerve roots?
C6,C7
how many CAG repeats are present in IT15 in juvenile onset huntingtons?
CAG>60-70
which causes more perinatal deaths, neural tube defects or congenital heart defects?
CHD
tuberoinfundibular pathway
DA pathway from hypothalamus to infundibular region (median eminence). DA released here *inhibits prolactin release from ant pituitary*
mesolimbic pathway
DA pathway from ventral tegmental area to nucleus accumbens. affects motivation, emotions, reward
mesocortical pathway
DA pathway from ventral tegmental area to prefrontal cortex, involved in cognition/executive functions
nigrostriatal pathway
DA pathway projecting from substantia nigra PC to the striatum, involved in stimulating/planning purposeful movement
name some agonists of dopamine receptors D-2, 3, and 4
DA, bromocriptine
benserazide
DOPA decarboxylase inhibitor, which is unable to cross the blood-brain barrier
where are declarative memories and procedural memories stored?
Declarative memories are dependent upon forebrain and limbic structures. Procedural memory (with a strong motor component) is dependent upon the cerebellum
DNMS
Delayed non-match to sample; a test of recognising objects (*recognition memory*) that have been seen recently (over seconds to minutes).
give some psychological symptoms of depression
Depressed mood, Anhedonia, Low self-esteem, Guilt, Cognitive deficits, Poor concentration, Feeling of 'hopelessness', Suicidal thoughts, Hypochondria
name some agonists of dopamine receptors D-1 and D-5
Dopamine, aka DA. Amphetamine (indirectly... it releases DA)
difference between EOAD and LOAD
Early onset alzheimers disease = before 65. much less common. LOAD is after 65 yrs old - much more common (97% of cases)
what is EPSP
Excitatory post-synaptic potential. synaptic potential that makes a postsynaptic neuron more likely to generate an action potential, due to postsynaptic influx of cations causing depolarisation
EPS
Extrapyramidal symptoms; movement disorders like spasms, parkinsonism and dyskinesia, often side effects of anti-psychotic drugs
general anaesthetics exert their main effects on which bodily system?
CNS
glioma
CNS tumour arising from glial cells. rarely curable, with a poor prognosis
describe plasticity in pain system at a spinal level
Central sensitization, long-term potentiation, disinhibition
why does opening of postsynaptic Cl- channels cause an IPSP?
Cl- flows in down its conc gradient, making the membrane potential more negative and less likely to reach threshold (hyperpolarisation)
IT15 gene codes for what? what is the gene aka?
Codes for huntingtin, a protein which is mutated in huntingtons disease. Is aka Huntingtin gene, HD gene or HTT gene
name 2 neurodegenerative diseases linked to *prion protein* aggregation
Creutzfeldt-Jakob-Disease, Gerstmann-Straussler-Scheinker-syndrome
which fungus can cause meningitis
Cryptococcus neoformans - typically more indolent presentation. - Immunosuppressed (especially HIV and transplant recipients)
what is the difference between Gi and Gs proteins?
Gi are inhibitory (decrease cAMP), Gs stimulatory (increase cAMP).
name all the cranial nerves
I Olfactory II Optic III Oculomotor IV Trochlear v Trigeminal VI Abducens VII Facial VIII Vestibulocochlear IX Glossopharyngeal X Vagus XI Accessory XII Hypoglossal
why are inner hair cells and outer hair cells described as active and passive?
IHCs passively react to the travelling soundwave in the basilar membrane by opening channels/releasing neurotransmitters... whereas OHCs react by *actively* changing shape
which neurotransmitters do neurons of the ventrolateral preoptic nucleus contain? are they excitatory or inhibitory?
GABA and galanin (Gal), both inhibitory
opiods inhibit what to reduce dopamine?
GABA neurons
are GABA receptors ionotropic or metabotropic?
GABA*A* is *ionotropic* (a chloride channel) and GABA*B* is *metabotrophic*
benzodiazepines rely upon which neurotransmitter to function?
GABA. they accentuate GABA A receptor opening of Cl- channel
what is meningitis
Inflammation of the meninges - layers of connective tissue surrounding the brain and spinal cord, forming the blood-brain barrier
where in the CNS is the 'switch' from urine storage to micturition initiated?
Pons Micturition Centre in the brain stem
how does pleasure affect sensitivity to pain?
Positively rewarding activities generate analgesia - due to endogenous opiate peptides & cannabinoids, and dopamine pathways
age-related hearing loss is AKA?
Presbycusis
what is the link between psychological distress, acute pain, and chronic pain?
Psychological distress and intensity of acute pain predict development of acute into chronic pain - from injury, surgery, illness, etc
how on an ECG can you easily classify arrhythmias into supraventricular or ventricular?
QRS complex wider than 3 squares = ventricular, QRS narrow = supraventricular
which is more potent, R-(+)-etomidate or S-(-)-etomidate?
R-(+)-etomidate is 5 to 10 times more potent as a general anaesthetic
which type of sensory receptor only responds to a *change* in stimulus/pressure?
RA (rapidly adapting)
which is more sensitive, RA1 or RA2 receptors?
RA2 (pacinian corpuscle - larger and high sensitivity)
in which part of the night is most REM sleep?
REM
in which stage of sleep does dreaming occur?
REM
in which stage of sleep are eye movements most prominent
REM sleep
which of these ions are more concentrated inside the cell than outside: Ca, K, Na, Cl?
K
AMPAR and NMDAR allow which key ion to *exit* postsynaptic neurons?
K+ (they are non-specific cation channels, so alongside influx of Na+ etc, K+ will flow out down its conc gradient)
why is an increase in extracellular K+ so dangerous?
K+ ion is essential for coordinating resting potential; a raised extracellular conc would decrease the concentration gradient (usually much more K+ inside cell than out) and depolarises cells - would kill you rapidly
what is the formula for the supply of the extraoccular muscles
LR6(SO4)3
LTM
Long term memory: a system assumed to underpin the capacity to store information over long periods of time
which has larger receptive field, SA1 or SA2 receptors?
SA2 (ruffini endings are musch larger than merkels fibres)
which two key morphogens begin to generate distinct ventral and dorsal spinal cell types in development?
SHH and BMP (bone morphogenic proteins)
venlafaxine
SNRI antidepressant; blocks serotonin and noradrenaline reuptake (SNRI)
citalopram
SSRI antidepressant. highly selective for blocking SERT
which are the preferred drugs to treat depression
SSRIs
SSRI
Selective serotonin re-uptake inhibitors. treat depression + anxiety. they limit reabsorption of serotonin into presynaptic neurones, increasing 5HT in the synapse
moclobemide blocks which enzyme?
MAO A
which MAO type metabolises noradrenaline and 5-HT?
MAO A
phenelzine and tranylcypromine block which enzyme?
MAO A and MAO B
which MAO type metabolises dopamine?
MAO A and MAO B
which MAO type metabolises tyramine?
MAO A and MAO B
in which major disease does the myelin around CNS neurons degenerate?
MS
what is the commonest demyelinating disease?
MS
oligodendrites degrade in which major disease?
MS (causes the decrease of myelin)
which diseases are likely causes of internuclear ophthalmoplegia
MS (in young) or stroke (in elderly)
name 4 opiod receptors
MU, DELTA, KAPPA, ORL1
schemata
Models of the world that provide a framework for the interpretation of new and stored information
describe plasticity in pain system at a supraspinal level
Modulation and modification of nociceptive and antinociceptive synaptic transmission
give 6 antidepressant medical treatments
Monoamine oxidase inhibitors, Tricyclic antidepressants, SSRIs, NRIs, Mixed action, Electroconvulsive therapy
3 common causes of sudden visual loss
Most vascular events, Retinal detachment, Acute angle closure glaucoma
chemical formula of nitrous oxide
N2O
which general anaesthetic has been linked to megaloblastic anaemia?
N2O
neurons of the locus coeruleus contain which neurotransmitter
NA
why is glutamate considered a target for schizophrenia treatment? why might it be dangerous to target?
NMDA antagonists mimic some positive and negative symptoms of schizophrenia. however, too much glutamate can be neurotoxic, stimulating opening of ion channels and influx of Ca2+, resulting in mitochondrial stress and overproduction of ROS - leading to cell death
ketamine, N2O and xenon are non-competitive agonists of which major receptors in the CNS?
NMDA glutamate receptors
name 2 glutamate receptors
NMDA receptor, AMPA receptor
which major glutamate receptors enable transport of calcium ions
NMDA receptors
purkinje cells of cerebellum lack which key glutamate receptors
NMDARs
which has a larger synaptic cleft, NMJ or CNS synapse?
NMJ
chemical formula of nitric oxide
NO
carbamazepine
Na+ channel blocker taken as a tablet which is good at relieving neuropathic pain in trigeminal neuralgia
what are class I anti-dysrhymic drugs? give examples
Na+ channel blockers. 3 groups; *1a* eg disopyramide , *1b* eg lidocaine, *1c* eg flecainide
negative cognitive triad
Negative view of the self, the world and the future
which two key receptors does ACh act on as a neurotransmitter
Nicotinic (fast, ionotropic) and muscarinic (slow, metabotropic)
4 lobes of cerebrum
Occipital, Parietal, Frontal, Temporal
which receptors does ATP act on as a neurotransmitter in the CNS?
P2X (fast, ionotropic) and P2Y (slow, metabotropic)
primary motor cortex is abbreviated to what?
PMC
pedunculopontine tegmental nuclei
PPT nuclei: found in the tegmentum of the brainstem. Send cholinergic neurons to many forebrain targets eg thalamus + basal ganglia, involving them in alert/attentiveness, reward, movement and REM sleep
mutations in which gene is the most common cause of familial alzheimers
PSEN1 (presilin 1)
what is the general outline of a somatosensory afferent pathway from the periphery into the CNS?
Peripheral nerves, dorsal root ganglia, sensory terminals in spinal cord grey matter, pathways to the brain
most drugs which treat psychosis focus on metabolism of which substance?
Pi
what causes fast/exaggerated tendon reflexes?
UMN lesions, hyperthyroidism, cerebellar disease
polyneuropathy
damage or disease affecting peripheral nerves (peripheral neuropathy) *across both sides of the body*, usually spreading from the feet and hands centrally
brown-sequard syndrome
damage to one half of the spinal cord, resulting in paralysis and loss of proprioception on ipsilateral side below lesion, and loss of pain and temperature sensation on contralateral side (due to where nerve tracts decussate in spinal cord)
what does a lack of pupillary light reflex indicate? why?
damaged optic/oculomotor nerve (eg by brain swelling) or brain stem death
taste sense is carried in which cranial nerves
VII and IX (facial and glossophrngeal)
hearing and vestibuar function is carrier in which cranial nerves
VIII (vestibulocochlear nerve, aka auditory nerve)
side effects of anaesthetics
death if overdose,
what is the relationship between decibels and Bels?
decibel = 1/10 of a Bel
how does accomodative power of lens change with age?
declines from birth
most of the caudal medulla is taken up by what?
decussation of pyramids
role of schwann cells in axonal regeneration
dedifferentiate and proliferate to create a permissive environment for axonal regeneration. help remyelinate
is body muscle more active in light or deep sleep?
deep sleep (body is capable of movement eg adjusting position - whereas in REM, muscles except eyes are paralysed
how does huntingtons disease affect basal ganglia
degeneration of striatal neurons projecting to GPe causes disinhibition of indirect pathway
subacute combined degeneration of spinal cord
degeneration of the dorsal/lateral columns of cord due to vitamin B12 deficiency, usually associated with pernicious anemia
spondylosis
degenerative osteoarthritis of the joints between the center of the vertebrae. common cause of back pain in elderly
is the activation of K+ channels in action potentials rapid or delayed?
delayed
function of pain
demands attention so you look after yourself. prioritises escape and promotes recovery and healing of wounds. also *teaches* us to avoid things that hurt
which is usually thinner, the dendrites or axon of a neuron?
dendrites
is ACh increased or depleted in cerebral cortex of alzheimers patients?
depleted (hence AChE inhibitors are given)
which two findings are required for the clinical diagnosis of alzheimers in a post mortem brain?
depositis of plaques (beta amyloid) and neurofibulary tangles (tau)
pregabalin
derivative of GABA given to treat epilepsy, anxiety + neuropathic pain. increases GABA biosynthesis, and binds to calcium channels
name 2 class IV anti-arrhythmic drugs
Verapamil and diltiazam
name 4 main causes of painless visual loss
Vitreous Haemorrhage, Central retinal artery or vein occlusions, Arteritic or nonarteritic anterior ischaemic optic neuropathy, Age-related macular degeneration(ARMD)
lateral medullary syndrome is AKA
Wallenberg syndrome or posterior inferior cerebellar artery syndrome
heredodegeneration
describes disorders which become gradually worse (usually neurodegenerative) that are passed down from one generation to the next.
extra-axial
descriptive term to denote lesions that are external to the brain parenchyma
in vivo, imipramine is metabolised within minutes into which compound?
desipramine (a NA uptake inhibitor)
what is the effect of suprachiasmatic nucleus lesions?
destroys 24hr circadian rhythm of sleep/wake + activity. however, sleep patterns still coordinate to match light and dark
what is *the* major cause of autonomic dysfunction clinically?
diabetes mellitus (can cause impotence, impaired bladder function, disordered gut motility (intermittent diarrhoea and constipation), altered BP control)
how is RA and SA sensory information processed differently in the cortex?
different columns in each area of the homunculus map in the somatosensory cortex
how do we hear *pitch* ?
different frequencies of sound get a peak vibration in different places on the basilar membrane (due to its structure). The point of peak vibration of the basilar membrane causes the most bending of the stereocilia, so elicits the most response from the hair cells in that part of the cochlea.
dysarthria
difficult or unclear articulation of speech that is otherwise linguistically normal
reticular activating system
diffuse network of nerve pathways in the brainstem connecting the spinal cord, cerebrum, and cerebellum, and mediating the overall level of consciousness
DWI
diffusion weighted imaging; form of MRI based upon measuring the random motion of water molecules within a voxel of tissue; useful for tumours and cerebral ischaemia
where is the subthalamus
directly below the thalamus and above the mammillary bodies. posterior to hypothalamus
receptor potential
a *graded* transmembrane potential difference produced by activation of a sensory receptor (usually caused by inward current flow)
describe the neurons in the *general sensory* pathway
a *primary afferent/first order neurone* runs from the receptor into the ipsilateral CNS via either a spinal nerve or the trigeminal nerve. this links to an ipsilateral *second-order neurone* which decussates and ascends to thalamus. *third order neurone* projects from thalamus to somatosensory cortex
which cognitive abnormalities are seen inunipolar depression
a bias towards negative material seen in memory, attention.
lesions in multiple sclerosis often surround which structure? why?
a blood vessel, because this is how the T cells make their way into brain
commisure
a bundle of nerve fibers that cross the midline at their level of origin or entry
typology
a classification according to type
basal ganglia
a collection of subcortical nuclei at the base of the forebain, involved in voluntary movement, procedural learning and habitual behaviour.
rhodopsin
a coloured, light-sensitive protein present in the rods of the retina. helps activate the visual phototransduction pathway by *closing Na+ channels in rod cells in response to light*. also gives the retina its purplish-red colour
full thickness corneal laceration
a cut on the cornea which strikes deep enough to go completely through the cornea, causing a ruptured globe - very painful, weeping eye. iris tissue can prolapse into lesion
detrusor-sphincter dyssynergia
disease where urethral sphincter contracts at the same time as the bladder contracts - results in impaired voiding which can eventually lead to kidney failure. consequence of a neurological pathology such as spinal injury.
syringomyelia
disorder in which a fluid-filled cavity (syrinx) forms within the spinal cord, expanding + compressing nerve fibres in that transverse section of the spine-usually cervical (muscle wastage in hand/loss of sensation + pain)
subfalcial herniation
displacement of the cingulate gyrus from one hemisphere to the other, under the falx cerebri
cytotoxic oedema (brain)
disruption in cell metabolism impairs functioning of Na/K pump in the glial cell membrane, leading to swelling of individual glia/neurons with sodium and water
how might disturbed sleep patterns cause depression?
disturbed sleep has been linked to decreasing memory retention, particularly of *positive events* more than negative events
potassium-sparing diuretic
diuretic drugs that do not promote the secretion of potassium into the urine; used in hypertension/congestive heart failure. eg spironolactone
left/right visual hemi-field
division of the full visual field down the midline into left and right
SOD-1
a gene which codes for multiple enzymes which destroy free superoxide radicals in the body. can exibit a vast array of different mutations - all of which give rise to motor neuron disease
frequency tuning curve
a graph of auditory threshold intensity at various frequencies for a single neuron
psilocybin
a hallucinogenic alkaloid, found in some toadstools
engram
a hypothetical permanent change in brain/physical storage of *memory*
what does 'stigma' mean in greek?
a mark made by a pointed object
what is PA2?
a measure of the affinity of a competitive antagonist for its receptor
role of NO in the body
a messenger; inhibits vaso-adhesion+constriction(particularly in erections - viagra enhances this effect)/modulator of hair cycle/neurotransmission/secreted as free radicals in immune response/
which gene causes huntingtons
a mutated version of huntingtin gene (codes for huntingtin protein)
Oculomotor nucleus
a nucleus in the midbrain, which lies in the gray substance of the floor of the cerebral aqueduct, and gives rise to the oculomotor nerve
MDMA toxicity
a parallel reaction to the tyramine cheese reaction; MDMA blocks MAO, causes VMAT 2 to release seratonin cargo uncontrollably. can cause death
blind spot
a part of the visual field (*not eye itself*) where light falls on the optic disc, which has no light sensitivity
red nucleus
a pink structure in the rostal midbrain involved in motor coordination. relays info from motor cortex + cerebellum to cerebellum (via inferior olivary complex) and contralateral rubrospinal tract
which risk factor is 2nd to age for alzheimers
a positive family history (Genetic factors estimated to account or 30%-70% of risk)
cathine
a psychoactive CNS stimulant drug, with 10-15% the potency of amphetamine (not to be confused with caffeine!)
define: sleep
a readily reversible state of reduced responsiveness to, and interaction with, the environment
sound spectrum
a representation of a sound in terms of the amount of vibration at each individual frequency. usually presented as a graph of pressure as a function of frequency
VEGF
a signal protein produced by cells that stimulates vasculogenesis and angiogenesis; produced when blood circulation is inadequate
oto-acoustic emissions
a sound which is generated from within the inner ear
rexed laminae
a system of ten layers of grey matter to label portions of the grey columns of the spinal cord
tianeptine
a tricyclic antidepressant with a difference; it has been shown to *increase* monoamine uptake, increase BDNF, and indirectly alter glutamate activity
which instrument could you compare the basilar membrane to?
a xylophone (gets wider and lower pitch towards apex)
perinatal deaths
babies which die before reaching a month old - includes stillbirths
are photoreceptor cells found in the back or front layer of the retina?
back (seems impractical but there we go)
what are the 5 most common body locations of chronic pain in europe?
back, knee, head, leg, joints
difference between bacterial and viral conjunctivitis?
bacterial is more 'sticky' and pussy, whereas viral is more watery. bacterial has a lesser degree of erythema
oligoclonal bands
bands of immunoglobulins secreted by plasma cells that are seen in electrophoresis of blood serum/CSF. if seen permanently in CSF, suggests MS
thermoreceptors
bare nerve endings in skin, cornea, bladder. can be either warm (detect warming >37oC) or cold (detect cooling <37oC). sensitive to changes of <0.1oC + have small segregated receptive fields; tiny warm- and cold-sensitive patches alternate across skin surface
name the grey matter surrounding the (white) internal capsule
basal ganglia
is the basilar membrane stiffer at the base or the apex?
base (about 100x stiffer)
what is the difference between Ia, Ib, and Ic antiarrhythmic agents
based on how fast they associate/dissociate with sodium channels: Ia is medium, Ib fast, Ic slow.
which dopamine receptors are inhibitory?
basically all of them (D-1 to D-5)
which two arteries feed the circle of willis
basilar and internal carotid
auditory transduction
basilar membrane moves up and down, stereocilia of the inner hair cells rub against the tectorial membrane. The bending of the stereocilia produces electrical response in the hair cells
which is superior in the brain, meyers or baums loop?
baums
which pathway in the optic radiation enables you to see inferior visual field?
baums loop
why does the current of Na+ ions flowing through channels decrease whilst more and more Na+ channels are opening?
because as more channels open, cell membrane gets nearer to the equilibrium potential of Na+ (which is no net movement of ions across membrane)
why is the resting potential of most cells close to the equilibrium potential of K+?
because at rest, the cell membrane is most permeable to K+ than to other ions (ie, more channels for K+ are open than for other ions in unstimulated cells)
why do rods provide less detailed images than cones?
because hundreds of them can connect to a single ganglion cell, meaning your brain can't distinguish between which individual rods are firing (whereas each cone has one ganglion cell to itself)
meyer-overton rule
because inhalation agents act through the lipid-rich CNS cells, anesthetic potency increases with lipid solubility
why should you always ask patients if they have any heart problems before giving lignocaine anaesthetic?
because it is also an anti-arrhythmic (interferes with heart rhythm
why is hippocampus referred to as a 'time machine'
because it is essential for episodic memory, which can be described
why might EpiPens be inefficient in a patient taking beta-blockers?
because salbutamol will have no effect
why might people with hearing aids report difficulties distinguishing sounds in background noise
because when outer hair cells are damaged, hearing aids can only amplify incoming sound, not replace the active 'sharpening' of sound wave that OHC prestin contraction enables
do ascending dorsal column neurons synapse before or after they decussate
before
name the two components to consciousness + their respective control systems
being *awake/alert* (reticular activating system) and being *aware* (cerebral cortex)
steognosis
being able to pick things up and work out what they are without looking; function controlled by parietal lobe
how do you interpret a glasgow coma scale score?
below 8 = coma. 9-12 = moderate head injury. above 12 = mild head injury
fasciculus gracilis receives info in which levels of the spinal cord?
below T6
the left spinal cord is lesioned. on which sides are the senses of pain, temp, proprioception, vibration and touch lost?
below the lesion, pain and temp are lost on the right hand side, and most touch, vibration and proprioception is lost on the left hand side
why can barbiturates kill you, but benzodiazepines not?
benzodiazepines bind to GABA A receptors and increase effect of GABA to open Cl- pore. barbituates directly open CL- pore; body has less control of this
which adrenoceptors are present in heart?
beta 1 and beta 2 - both stimulatory
tremor is mediated by which adrenoceptors?
beta adrenoceptors
which brain wave type is seen in REM sleep
beta waves
name 4 *non BDZ* ligands which bind to benzodiazepine binding site on GABA A receptor. Which are endogenous?
beta-CCE (endogenous), zolpidem, zopiclone, desmethyldiazepam
which proteins aggregate in alzheimers disease
beta-amyloid4 and Tau
normal eye pressure
between 10 and 21mmHg
which two cell types are all rods and cones in direct contact with?
bipolar cells and horizontal cells
which cells connect the rods and cones to the optic nerve?
bipolar cells followed by ganglion cells
bitemporal heminopia
blindness in temporal visual field of both eyes, caused by lesion of optic chiasm (only affects the fibres which are crossing in the chiasm, hence the fibres which see your nasal visual field are preserved)
entacapone
blocks COMT; often used as an add-on parkinsons drug to reduce breakdown of L-DOPA
Benzhexol
blocks actions of ACh in striatum; used to be used for parkinsons but can cause cognitive amnesia. now used for drug-induced parkinsons only (eg schizophrenia patients)
name the extra layer of surrounding epithelial cells of all blood vessels in the brain
blood-brain barrier
what restricts movement of immunologically important cells/molecules into the brain parenchyma
blood-brain barrier
Cytotoxic cerebral oedema
blood-brain barrier is intact but ion pumps in brain cell membranes are impaired by toxins, leading to cells swollen with water
what colour is the bone, grey matter, and white matter, fat, and air in CT scan?
bone is white, grey matter is light grey, white matter darker. air and fat are both black - don't get confused
how is the location of the preganglionic neurons different between symp- and parasympathetic nervous systems
both are within the CNS, but symp are within thoracolumbar segments T1-L2, and parasymp are found within sacral segments S2-S4 + specific nuclei in brainstem.
why is spirinolactone potentially lethal if combined with ACE inhibitor therapy?
both drugs raise potassium (especially dangerous in renal failure)
name 2 drugs from each of class Ia, Ib, and Ic of antiarrhythmic drug
a: quinidine, procainamide. b: lignocaine, phenytoin. c: encainide, ecainide
two point discrimination
ability to discern that two nearby objects touching the skin are truly two distinct points, not one. reflects how finely innervated skin is
lewy bodies
abnormal aggregates of alpha-synuclein protein that develop *inside* nerve cells in Parkinson's disease, Lewy body dementia + other disorders.
strabismus
abnormal alignment of one or both eyes; a squint. must be corrected in childhood for CNS development
astrogliosis
abnormal increase in the number of astrocytes due to the destruction of nearby neurons
catatonia
abnormality of movement and behavior arising from a disturbed mental state (typically schizophrenia) - lack of motivation to move
fasciculus cutaneus receives info in which levels of spinal cord?
above T6 (except face and ear)
above which spinal cord segment are there more than 2 dorsal column tracts of the spinal cord? How many are there?
above level T6. there are 4
abscess VS tumour
abscess is a swollen collection of pus within the tissues, usually due to infection. tumours are masses caused by abnormal proliferation of tissues
name two types of generalised seizure
absence seizures. tonic-clonic seizures
drugs taken by mouth tend not to have a high liability of dependency. why?
absorbed too slowly to produce a 'high' - there are exceptions eg alcohol and codeine.
what are the ABC and D treatments for hypertension?
ace inhibitors, beta blockers, Ca2+ channel blockers, diuretics
heroin is di-acetyl morphine. what is important about the two acetyl groups?
act as a carrier for the morphine so it crosses the blood brain barrier very quickly; this makes all the difference
how does parasympathetic stimulation affect the lungs?
act on smooth muscle of bronchi and bronchial arterioles to cause bronchoconstriction and vasoconstriction
what role does the cerebellum play in the vestibular reflex?
activated when the whole word slips - i.e. when your eyes move at different speed to head
why might an a2 agonist be used in glaucoma?
activates the α2-adrenoceptors on the ciliary epithelium, reducing cAMP concentrations and hence aqueous humour production. also increase uveoscleral outflow
why can't APs propagate along an axon without *active* membrane transport?
active Na+/K+ channels prevent the AP from fading as it propagates by allowing it to regenerate + run undecremented along axon
capsaicin
active component of chilli peppers, used as an analgesic in ointments/dermal patches/nasal sprays
5 checks of optic nerve
acuity, checking colour vision, visual field, reflexes, fundoscopy
red eye, mid-dilated pupil, clouded cornea, intense pain are characteristic of what?
acute angle closure glaucoma
how to differentiate between acute and chronic subdural haematomas on CT scan
acute are hyperdense (white) and chronic hypodense
in general, what are the main differences between acute and chronic pain?
acute pain: identifiable cause, resolves with healing, responds to treatment. chronic pain: much less likely to have those features. requires more psychological investigation
will patient's nystagmus adapt faster when spun in chair wearing a blindfold, or without blindfold? why?
adaptation (stable eyeball) occurs rapidly while *wearing blindfold*, but virtually doesnt occur without it. reason: when eyes are open, the *optokinetic reflex* can work to "remind body" that we are spinning, maintaining nystagmus even after endolymph has habituated and VOR is lost)
adjunct drug
added to another drug as a supplementary rather than an essential part
a loss of control over drug seeking behaviour is called?
addiction
synechia
adhesions between the iris and the lens or cornea resulting from trauma or eye surgery or as a complication of glaucoma or cataract; can lead to blindness
pneumoccal meningitis is most common in which age group?
adults
Internuclear ophthalmoplegia
affected eye shows impairment of adduction. When an attempt is made to gaze contralaterally, the affected eye adducts minimally, if at all. The contralateral eye abducts, however with nystagmus
does brown-sequard syndrome affect only the level of the lesion?
affects all sensory input at level of hemidissection on side of lesion, affects dorsal column below lesion on ipsilateral side, and spinothalamic below lesion on contralateral side
in which two key populations might Ca channel blockers be given to reduce hypertension?
african americans / elderly patients
in which two key populations might diuretics be given to reduce hypertension?
african americans / elderly patients
how does the somatosensory homunculus react to hand amputation and transplant of new hand?
after amputation, the face area invades upwards to occupy where the hand senses travelled (may feel phantom hand upon touching face). after transplant, hand signals area begins to restore.
what might causes an elderly lady to have a BP of 195/85mmHg, with a HR of 30bpm? how might you treat this?
age has caused bradycardia, which leads to longer filling time - hence greater CO, and a high systolic but low diastolic. treat by speeding up heart with a pacemaker
causes of hearing loss
age, loud noise exposure , ototoxic drugs (antibiotics eg gentamicin), genetic, stress (sudden hearing loss)
neurofibrillary tangles
aggregates of hyperphosphorylated tau protein most commonly associated with alzheimers.
Nucleus Tractus Solitarius
aka 'solitary nucelus' or NTS. nuclei forming column of grey matter in medulla, through which runs a white bundle of nerves - the 'solitary tract.' many functions including taste + autonomic reflexes
sylvian fissure
aka *lateral sulcus*. large diagonal fissure on the lateral surface of the brain that separates off the temporal lobe from frontal lobe
paraneoplastic syndrome
aka *non-metastatic* syndrome. disease/symptom caused by presence of cancer in the body, but not by local presence of cancer cells. effect is due to humoral factors excreted by/immune response to tumor cells
interstitial oedema (brain)
aka Hydrocephalus. CSF fluid oedema in periventricular white matter, due to a CSF drainage obstruction.
Subacute combined degeneration of spinal cord
aka Lichtheim's disease. degeneration of dorsal/lateral spinal coloums, affecting sensation/proprioception/lateral corticospinal tract. due to low vit B12 (often linked to pernicious anemia)
rexed's lamina II
aka substantia gelatinosa; dorsal part of the spinal cord grey matter where the first order spinothalamic neurons synapse
dejerine-roussy syndrome
aka thalamic pain syndrome. condition developed after stroke causing damage to thalamus. begins with numbness in contralateral side of body which develops into very severe chronic pain, with little treatment
spinal lemniscus
aka the anterior and lateral spinothalamic tracts
optic papilla
aka the optic disc - the area where the optic nerve enters the retina. is devoid of photoreceptor cells (blind spot)
hypervigilance
alertness; enhanced state of sensory sensitivity + exaggerated intensity of behaviors whose purpose is to detect threats. accompanied by a state of increased anxiety which can cause exhaustion
which vertebrae have transverse foramina?
all cervical vertebrae
5HT2a receptors are important why?
all drugs which activate them are class A controlled substances and are *all hallucinogenic* (LSD is included)
main visual areas of brain take up which lobes of the cortex?
all of the occipital cortex and much of the parietal and temporal cortex
out of the 7 5-HT receptors, which are excitatory?
all of them *except* 5-HT1 and 5-HT5
the left upper brainstem is lesioned. on which sides are the senses of pain, temp, proprioception, vibration and touch lost? why?
all of those sensations would be lost on the contralateral side, because all ascending somatosensory pathways decussate *in the spinal cord or lower brainstem*
why does post rotatory nystagmus last longer after spinning blindfolded?
along with vestibulo-occular reflex, the *optokinetic reflex* helps tell body that it has stopped spinning and is still; without vision, this cannot occur, so vision takes longer to stabilise
which adrenoceptors are found in the lungs?
alpha 1 - constrict, and beta 2 - dilate
which receptors are blocked by SSRIs
alpha 1 adrenoceptors, H1 receptors, muscarinic receptors
clonidine is an agonist of which receptor?
alpha 2 adrenoceptor agonist
benzodiazepines don't bind to GABA receptors with which alpha subunit?
alpha 4
which receptors 'blunt' the signal of monoamines in synapses?
alpha-2 adrenoceptors
which proteins aggregate in parkinsons disease
alpha-synuclein
Lewy bodies are composed primarily of what?
alpha-synuclein fibrils
ocular dominance columns
alternating bands in a striped pattern across the surface of the straite cortex (V1) that respond preferentially to input from one eye or the other. involved in *bilateral vision*
lesions can be used to destroy spinothalamic tracts to relieve pain. after months, pain comes back - why?
alternative tracts can learn to carry pain info, eg spino-parabrachial pathway
when does pain have a psychological component?
always
which is more common, parkinsons or alzheimers?
alzheimers (~ 10 times more common)
3 most common forms of dementia in order
alzheimers disease, vascular dementia, dementia with lewy bodies
skinner
american psychologist who believed free will was an illusion and human action depends on consequences of past actions. created 'behaviourism' and the operant conditioning 'skinner box'
tryptophan
amino acid which is necessary to make serotonin/ normal growth + metabolism. needs to be obtained from diet
classical neurotransmitters are which kind of chemical structures
amino acids (or derivatives of....eg catecholamines derived from tyrosine)
what is the main class III antiarrhythmic drug
amiodarone (though it also shows class I, II, III and IV action)
what was the difference between antidepressants and amphetamine in treating depression?
amphetamine would make patients "run to the bridge they were about to jump off of" - whereas antidepressants stop desire to jump.
how do your brainwaves change as you progress from REM through to stage 4 sleep
amplitude increases, and frequency decreases, through from beta rhythms to theta and delta
fear memories are 'stored' where in the brain?
amygdala
which old structure is important in the emotional response to pain?
amygdala
which part of brain seems to be involved in nondeclaratic classical conditioning emotional responses?
amygdala
name the key areas of the brain in the assessment of stimuli/decision making process/execution of commands
amygdala + parts of the cortex (especially prefrontal + insular cortex)
nordiazepam
an active metabolite of diazepam and other benzodiazepines, used primarly to treat anxiety
fornix
an arched structure in the body, in particular the area of white matter between the hippocampus and the hypothalamus
associative learning
an association between two stimuli or a behaviour and a stimulus is learned. The two forms of associative learning are classical and operant conditioning.
what is the medical definition of 'insult'
an event/occurrence which causes damage to an organ
describe 5-HT1 receptor, including agonists + antagonists
an inhibitory serotonin receptor - decreases firing of serotonergic neurons. agonists include 8-OH-DPAT and sumatriptan. antagonists include WAY 100635.
scotoma
an isolated area of diminished vision within the visual field
define pain in humans:
an unpleasant sensory *and emotional* experience associated with actual *or potential* tissue damage, or described in terms of such damage
main uses of ketamine
anaesthesia in: children, asthmatics, emergencies/war zones
why is recovery from anaesthetic longer in obese patients?
anaesthetics are very lipid soluble, and in long operations they can be absorbed into body fat. due to low blood flow of fat, may take weeks for effect to fully leave
what are the main actions of mu-opioid receptors
analgesia, resp depression, physical dependence, euphoria, miosis (pupil constriction)
superior quadrantanopia
anopia affecting a quarter of the field of vision. It can be associated with a lesion of an optic radiation
decussate
another word for ' cross or intersect '
foramen transversarium
another word for transverse foramen
difference between antagonist and inverse agonist
antagonists don't do anything themselves unless in conjunction with an agonist, which they block. inverse agonist binds to the same receptor binding-site as an agonist but produces an effect opposite to that of an agonist
what does a large PA2 value mean?
antagonists with a large PA2 have greater affinity to their receptors than ones with a small PA2
which corticospinal tracts *don't* cross the midline? what % of corticospinal fibres is this?
anterior (direct) corticospinal tract. about 5% of the fibres
difference between V1 ventral stream and dorsal stream?
both pathways from primary visual cortex, but ventral goes through V2 then V4 to the inferior temporal cortex; recognises objects. dorsal goes through V2, V6 and V5 to posterior parietal cortex; linked to object location/motion/contol of eyes & arms
which key vessels can be seen in a lateral view internal carotid angiogram?
anterior and middle cerebral arteries (not posterior as this arises from basilar not carotid). opthalmic artery also visible
which cortical areas are supplied by the anterior, middle and posterior cerebral arteries individually?
anterior cerebral arteries supply the anteromedial portion of the cerebrum. The middle cerebral arteries are situated laterally, supplying the majority of the lateral part of the brain. The posterior cerebral arteries supply both the medial and lateral parts of the posterior cerebrum
which arteries form the circle of willis
anterior cerebral arteries, anterior communicating artery, internal carotids, posterior cerebral arteries and the posterior communicating arteries
which artery supplies most of the superior medial surface of the brain hemispheres?
anterior cerebral artery
which artery is likely to cause a stroke which affects lower limbs only?
anterior cerebral artery (affects medial brain)
in the anterior cranial fossa, which artery usually causes epidural haematoma
anterior ethmoidal artery
circumciliary injection around the iris, photophobia, pain, misshapen pupil, and inflammation in anterior chamber is characteristic of which eye disease?
anterior uveitis
difference between anterior and posterior synechiae
anterior: iris adheres to cornea. posterior: iris adheres to lens
what are the boundaries of the parietal lobe?
anteriorly, the central sulcus. laterally, the lateral fissure. posteriorly there is no distinct boundary but medially there is a medial parieto-occipital sulcus
antidysrhythmic drugs AKA?
antiarrhythmic drugs
gabapentin
anticonvulsant used to control some types of seizures in the treatment of epilepsy; also used to manage neuropathic pain. Can cause confusion, so patients don't like taking it for long time
mianserin
antidepressant, anxiolytic, antiemetic and antihistamine drug which blocks histamine, serotonin, and alpha-adrenergic receptors. disinhibits release of NA, DA, 5HT, ACh.
most anti-anxiety drugs are also which kind of drugs?
antidepressants
what is the 'therapeutic lag' of antidepressants?
antidepressants usually take weeks/months to affect mood, even though chemical changes (eg serotonin increase) occur within hours. thought to be due to the body *downregulating* 5HT-1 receptors (timeconsuing genomic process)
how does the main neurotransmitter/receptor used by neurons differ between symp- and parasympathetic nervous systems?
both use ACh in the ganglion (nicotinic receptors), but symp uses NA at the effector (adrenoceptors) - except for sweatglands - whereas parasymp has ACh at the NMJ (muscarinic receptors)
where in cell is MAO found?
bound to outer membrane of mitochondria
tonsillar herniation
brain herniation where the cerebellar tonsils descend below the foramen magnum
list factors which could cause increased intracranial pressure
brain oedema (infarction/trauma/infection) haemorrhages, brain tumour/abscess, CSF drainage obstruction
where are opoid receptors found in body?
brain, brainstem, spinal cord, and peripheral tissues
theta waves
brainwaves detected via EEG in children and adults in light sleep
neuropathology
branch of medicine concerned with diseases of the nervous system, including brain biopsy/autopsy
central retinal artery
branch of ophthalmic artery that penetrates the optic nerve to enter eye at the optic papilla in the retina. divides into superior and inferior temporal and nasal arterioles
lenticulostriatal arteries
branches of the proximal middle cerebral artery, which supply the basal ganglia and internal capsule
what are the causes of vasogenic oedema
breakdown of the tight blood-brain barrier junctions due to *tumour/trauma/haemorrhage/infarction/abscess/lead intoxication*
tics
brief, involuntary movements which remain stereotyped in an individual through life; often emerging in times of stress
the great commisure
broad nerve cable + lesser bridges which connect the two halves of the brain; people function almost normally with this cut, but children who are *born without* it have major issues
corpus callosum
broad transverse white matter tract below the cingulate gyri connecting the two cerebral hemispheres
difference between wernikes aphasia and broca's aphasia
brocas is expressive - difficult to form words as a motor function. wernikes is receptive - can speak but wont make sense
name condition caused by spinal cord hemisection
brown-sequard
which disease presents with a loss of pain+temp contralaterally, and loss of touch+proprioception ipsilaterally?
brown-sequard syndrome
what causes hydrocephalus?
build up of CSF expanding ventricles of brain, due to blockage in flow of CSF
proptosis
bulging of the eye anteriorly out of the orbit
name some ventricular arrythmias
bundle branch blocks (between AVN and purkinje fibres), *ventricular tachyarrhythmias* eg ventri ectopic beats, ventric tachycardia, ventric fibrillation, torades de pointes
anterior commisure
bundle of nerve fibers (white matter), connecting the cerebral hemispheres across the midline in front of the columns of the fornix
dyskinesia
any abnormality in performing voluntary movement
sulci
any of the narrow grooves in an organ or tissue especially the brain surface
consensual response
any reflex observed on one side of the body when the other side has been stimulated, eg if if right eye is shielded and light shines into left eye, constriction of both pupils occur
difference between disarthria and aphasia
aphasia is disorder of language (understanding etc), disarthria is disorder of speech (slurring etc)
pain in T10 - T12 dermatomes could be referred from where?
appendix (if only T10) or testes, prostate, ovaries, uterus
driaze test
apply drug to eye surface to test for toxicity
limbic cortex
arc-shaped region of cortex; 'old' part of brain. controls the basic emotions (fear, pleasure, anger) and drives (hunger, sex, dominance, care of offspring)
which part of the medulla is an extension of the pontine nuclei of the pons, with the same cortico-cerebellar motor function?
arcuate nuclei
substantia gelatinosa
area at apex of the posterior grey column, aka rexed lamina II. contains many opiod receptors and is one of areas where 1st order spinothalamic tract neurons synapse
parasympathetic nucleus ambiguus
area in medullary reticular formation, contains parasympathetic neurons for slowing/weakening heart contractions (via the vagus)
entorhinal cortex
area in the medial temporal lobe and functioning as a hub in a widespread network for forming spatial memory and navigation. The EC is the main interface between the hippocampus and neocortex
broca's area
area located in left frontal lobe near lateral fissure important for motor production of speech
meningitis belt
area of africa with many epidemics, mostly due to *type A* meningitis, which has no vaccine
wernicke's area
area of cerebral cortex essential for understanding + forming language. only present on the dominant hemisphere, not both
primary auditory cortex
area of cerebral cortex; receives info from both ears
binocular visual field
area of the visual field which is an overlap between left and right hemi-fields
why might a drug be given sublingually?
area under the tongue has many capillaries so the drug can be absorbed directly into bloodstream without going through GI tract; so is usually faster and more effective.
how does the somatosensory cortex change after amputation?
area which supplies that limb will shrink over time
brodmann areas
areas of cerebral cortex based on histology - they relate suprisingly well to function
striate arteries
arise from the middle cerebral artery and supply deep structures in the cerebrum including the internal capsule and reticular formation. Strokes in these vessels are common and can cause extensive damage
red nucleus controls what aspect of typical walking?
arm swing
common general features of local anaesthetic chemical structures
aromatic group one end, and tertiary/secondary amino group the other end. linked by ester OR amide bond
which frequencies does noise induced hearing loss most affect?
around 4000 Hz
at which age does presbyopia set in?
around 45
most meningioma cases are at which age?
around 60
which vertebral level is behind the entry to the larynx?
around C4/5
which muscles cause hairs to stand up?
arrector pili
what causes locked-in syndrome
arterial disruption at the pons - branches of basilar artery supply pons, and some branches supply motor tracts and not sensory. damage to these causes locked-in syndrome
Beta 2 adrenoceptors are found in which kind of blood vessels?
arteries/arterioles to skeletal muscle (eg including coronary arteries)
AVM
arteriovenous malformation; abnormal connection between arteries and veins, bypassing the capillary system
what are the 4 most common causes of pain in europe?
arthritis, herniated/deteriorating discs, traumatic injury, migraines
meprobamate is licensed to treat which conditions?
as a muscle relaxant eg for MS -no longer licensed as anti-anxiety drug due to misuse
how does the central canal ascend in the brainstem?
as it ascends, passes dorsally, eventually opening into the diamond shaped 4th ventricle below the cerebellum
from their source, do tactile and proprioceptive tracts ascend on ipsilateral or contralateral side of the spinal cord
ascend ipsilaterally in the dorsal columns to dorsal column nuclei, after which they decussate to contralateral side
anterior spinothalamic tract
ascending pathway in outer latero-ventral edge of spinal cord. associated with conduction of soft nociceptive information to the reticular formation in the thalamus
spinoreticular tract
ascending pathway in the white matter of the spinal cord, positioned close to lateral spinothalamic tract. goes from spinal cord—to reticular formation— to thalamus. responsible for automatic responses to pain, such as in the case of injury
how do you assess pain when it is so subjective?
ask patient - verbal or numerical scale is the best way. Could use HR, BP, fMRI etc...but there are many other influences involved in those.
gate control model
asserts that non-painful input closes the "gates" to painful input, which prevents pain sensation from traveling beyond the dorsal horn. Therefore, stimulation by non-noxious input is able to suppress pain
which cells form the blood brain barrier around blood vessels?
astrocytes
what are the key clinical features and lab tests that aid diagnosis of MS?
at *least two lesions* in the CNS, separated in time and space. plaques seen in MRI of brain/spinal cord. *lumbar puncture*increased active lympocytes, raised protein, oligoclonal bands on electrophoresis. delayed conduction in visual pathways seen in VEP
how does demyelination affect AP conduction down axons?
at first, causes AP conduction to be blocked. over time, conduction is restored as Na+ channels become expressed - but is much slower
at what stage is the CNS first divided into forebrain, midbrain, hindbrain, and spinal cord?
at the end of neurulation
what is being off-balance due to cerebellum called?
ataxia
which drug would you give if a patient has an unshockable heart rhythm?
atropine
downsides of atypical neuroleptics vs typical neuroleptics
atypical have all the side effects of typical, plus more... a scary one being agranulocytosis
what kind of hallucinations are diagnostic of schizophrenia?
auditory - most often talking about you, eg your friends are plotting against you
describe the auditory pathway from the auditory nerve
auditory nerve fibre, ipsilateral cochlear nucleus, superior olivary nucleus, inferior colliculus, medial geniculate body, auditory cortex
superior temporal gyrus is involved in what function?
auditory processing
in a nutshell, how do all benzodiazepines work
augmenting effects of GABA at the GABA A receptor
pernicious anaemia
autoimmune attack destroys parietal cells in stomach, so they don't produce sufficient intrinsic factor for B12 absorption. leads to macrocytic anemia
vegetative system is AKA
autonomic nervous system
friedrich's ataxia
autosomal recessive mutation leading to reduced expression of mitochondrial protein frataxin, causing progressive nerve damage including ataxia
long-term memory
does not require continued rehearsal, has greater capacity and is quite resistant to disturbance from the brain (e.g. memory for familiar telephone numbers)
drugs with dependence-liability increase transmission of what in the nucleus accumbens?
dopamine
whcih enzyme is present in NA neurones but not dopamine neurons?
dopamine beta hydroxylase (enzyme which converts dopamine to NA)
what are the two main risks of just increasing dopamine in patients brain to treat parkinsons
dopamine can be converted to NA, which has many effects in the brain. also, often parkinsons is only loss of dopamine in one pathway in the brain; you don't want to overload the other pathways.
what key thing do these chemicals have in common: HALOPERIDOL CHLORPROMAZINE DOMPERIDONE?
dopamine receptor antagonists (uses include antipsychotics and antiemetics)
dopaminergic nigro-striatal pathway
dopaminergic pathway that connects the substantia nigra with the dorsal striatum - part of the basal ganglia motor loop
nigrostriatal system
dopaminergic pathway that connects the substantia nigra with the dorsal striatum. involved in movement production via basal ganglia
is the 'where' visual stream ventral or dorsal?
dorsal - projects to brodmann area 7 of parietal lobe - involved in proprioception/where an object is is space
which pathway contains *axons* of primary afferents, spinothalamic tracts, or dorsal column medial lemniscus pathway?
dorsal column medial lemniscus pathway (spinothalamic tract only contains the synapse of primary afferents entering spinal cord)
nucleus gracilis
dorsal column nuclei in medulla that participate in fine touch/proprioception of the lower body. contains second-order neurons of the posterior column-medial lemniscus pathway. sends axons that synapse in thalamus
name the 3 most important ascending spinal tracts and what they carry
dorsal columns (fasciculus gracilis and cuneatus): fine touch + proprioception to cerebrum. spinothalamic tracts - pain, temp, touch, pressure to thalamus. spinocerebellar tracts - muscle + joint receptor info to cerebellum
which part of brainstem contains dorsal column nuclei
dorsal medulla
tectum of midbrain
dorsal part of the mesencephalon, posterior to cerebral aqeuduct. responsible for auditory + visual reflexes
where is the 4th ventricle seen on the medulla?
dorsal surface; lies beneath cerebellum, ascends up into pons
name the main region in the spinal cord where grey matter extends out to the pia?
dorsolateral fasciculus (many unmyelinated axons)
what kind of joint is the temporomandibular joint
double synovial joint (two seperate synovial cavities, seperated by a flexible articular disc)
sialorrhoea
dribbling
side effects of neuroleptics
dribbling, hyperprolactinemia, sialorrhoea, EPS, aplastic anaemia, Neuroleptic malignant syndrome
carbidopa
drug given to people with Parkinson's disease in order to inhibit peripheral metabolism of L-DOPA. allows a greater proportion of peripheral L-DOPA to cross the blood brain barrier - boosts central nervous system effect of L-DOPA
phenacetin
drug introduced in 1960s which turned out to cause dangerous renal damage
practolol
drug introduced in 1970s, turned out to be extremely toxic and have adverse drug effects - lead to introduction of BNF yellow card
primary visual cortex is near which sulcus?
calcarine sulcus
what can abnormal hyperdense (bright) structures be caused by in head CT
calcifications or blood which has leaked out of vessels
otoconia
calcified deposits on top of the gelatinous ololihic membrane in a macula, which are affected by gravity and hence enable maculae to detect tilt information even when head is stationary
Hebb
came up with the idea that neurons which are connected and usually fire at the same time should be linked, as they are trying to represent the same thing; now called LTPs /connectionism.
how can we use the B2 adrenoceptors in the uterine muscle pharmacologically?
can agonise them to cause relaxation of the muscle (inhibits labour)
which antigens activate T cells to attack oligodendrocytes in MS?
can be MBP (myelin basic protein), PLP (proteolipid protein), MOG (myelin oligodendrocyte glycoprotein)
are benzodiazepines addictive
can be in industrial amounts -
what causes aneurysms?
can either be hereditary or acquired disease
why might fMRI be useful in treatment of brain tumour patient
can map areas of brain activation upon movements of eg speech can been seen in brain. can see how much these areas overlap with tumours; used to determine how aggressive surgeon can be (*surgical planning*)
tulving
canadian neuroscientist who separated declarative memory into 'semantic' and 'episodic'
which drug is usually used in partial seizures
carbamazepine
which drugs can you give to prevent L-DOPA being converted to dopamine outside the blood-brain barrier?
carbidopa
give 3 side effects of anaesthetics specific to halothane
cardiac arrhythmias, low BP, liver damage
digoxin
cardiac glycoside found in foxgloves (digalis species) which stimulates release of ACh. used in small doses to increase heart contractility and/or decrease heart rate
list factors which affect arterial pressure
cardiac output, total peripheral resistance, sympathetic and parasympathetic outflow, heart rate, stroke volume (and total blood volume)
disadvantages of ketamine
cardiovascular problems, increased intracranial pressure, red skin/rash, nausea, tonic-clonic movements, dependence, delerium/hallucinations, respiratory depression
is baroceptor reflex from carotid sinus or carotid body?
carotid sinus
dry eyes
dry, gritty, watering, sore, red eyes.
conductive deafness
due to interference with transmission of sound to the cochlea usually the result of obstruction of the ear canal/disease of middle ear
the dura mater consists of two fused layers, except in which locations?
dural venous sinuses, where the layers are unfused to form spaces for venous blood
beta rhythms are seen on an EEG when?
during normal waking consciousness, with eyes open
why is O2 given during recovery from some general anaesthetics
during recovery, anoxia may occur due to changing concentration gradients. giving extra O2 prevents this
sympathetic neuropathy
dying off of the sympathetic postganglionic neurons; frequent in diabetes type I and II
what is a growth cone?
dynamic, actin-supported extension of a developing axon seeking its synaptic target. has many projections called filopodia
slurred/ poorly articulated speech is called what?
dysarthria
which is more common, arrhythmia or dysrhythmia?
dysrhythmia
EPS side effects
dystonia (continuous spasms and muscle contractions), akathisia (motor restlessness), parkinsonism (rigidity, bradykinesia, and tremor), dyskinesia (jerky movements). occur from drugs like *typical antipsychotics* which agonise D2 receptors
signs/symptoms of parkinsons
Shuffling gait• Stooped posture• Freezing• Soft monotonic speech• Swallowing problems• Masked face• Executive dysfunctions -attention, impulse control,time, cues• Depression• Anxiety• Sleep• x 6 excess dementia
which mnemonic helps you remember the colour of CSF in T1 and T2 MRI scans
T t*w*o *w*ater is *w*hite (CSF is pretty much water)
grey matter is dark and white matter light. is this a T1 or T2 MRI?
T1
if ventricles appear dark on an MRI scan, is it T1 or T2?
T1
principle dermatomes for referred heart pain
T1-T8
principle dermatomes for referred appendix pain
T10
fat is not bright, white matter is dark, and grey brighter. is this a T1 or T2 MRI?
T2
name 2 key receptors involved in sensitising C fibres during inflammation
TRPV1 receptor and NGF:TrkA receptor
describe the anatomical steps in the pathway for memory formation from temporal lobe cortex/amygdala
Temporal lobe cortex, amygdala > dorsomedial nucleus of thalamus > prefrontal cortex
which 4 parts of the brain form the 'pain matrix'
Thalamus, somatosensory cortex, insula and anterior cingulate cortex
what does SMA stand for in the brain?
Supplementary motor area
name two common disorders causing cloudy optics
cataract (lens or cornea) and floaters (debris near retina)
which two conditions could interfere with stereopsis?
cataracts (congenital/those in young children). strabismus (squint)
in a patient taking alpha-adrenoceptor antagonists, why might EpiPens be dangerous in anaphalactic shock?
cause worse hypotension (activates the B2 receptors in vessels without the contradictory effects of a1)
how does opening of K+ channels in membrane cause inhibition of nerve impulses?
causes hyperpolarisation (more K+ can escape cell) and also decreases resistance and hence voltage change (more channels open)
how does hypoxia (with normal perfusion) change appearance of neurons?
causes them to become shrunken and eosinophilic (readily take up eosin dye)
amacrine cells
cells in retina which receive signals from bipolar cells. regulate bipolar + ganglion cell activity
what is the rhyme to remember the hebb rule
cells that fire together wire together, cells out of sync fail to link
is the mu opiod receptor peripheral or central?
central
what is the 1 *really* important branch of the opthalmic artery
central artery (of the retina)
scala media
central duct of cochlea; endolymph filled cavity inside the cochlea, located in between the scala tympani and the scala vestibuli
equatorial region of muscle spindle
central portion of muscle spindle - the non-contractile part, innervated by sensory afferents
pale retina with thin vessels is a sign of?
central retinal artery occlusion - starves retina of blood supply
why might touch start to feel painful after an injury?
central sensitisation; area of dorsal horn which senses pain expands to include the region which detects touch
difference between cerebellar and cerebral peduncles
cerebellar connect cerebellum to brain stem (superior, middle, inferior). cerebral peduncles are in anterior midbrain and connect the large sensory + motor tracts between the pons + cerebrum
name the grooves in the cortex of the cerebellum
cerebellar folia
which part of the cerebellum can potentially herniate through the foramen magnum?
cerebellar tonsils
2 types of mossy fibres
cerebellum and hippocampus
what is commonly blocked in hydrocephalus
cerebral aquaduct (between 3 and 4th ventricles)
name the dark hole seen in the posterior midbrain in T1 MRI
cerebral aqueduct
what are the 3 hallmark neuropathologies of alzheimers disease
cerebral atrophy, amyloid plaques, neurofibrillary tangles
which 3 tissues form the left + right cerebral hemispheres?
cerebral cortex (grey matter), subcortical white matter, deep nuclei (grey matter)
where do the principal afferent inputs to the basal ganglia come from?
cerebral cortex and thalamus
hyperpolarise
change in a cell's membrane potential that makes it more negative; the opposite of a depolarization
refraction
change in direction of a propagating wave (light or sound) when passing from one transparent medium to another
how can conditioned cues be used to treat drug seeking behaviour?
change/remove environmental cues - there will be a *conditioned place preference, place withdrawal, and tolerance* for drug seeking behaviour.
which structural changes are seen in the brain in those with chronic pain?
changes in activation patterns/descending modulatory system: inhibitory system underactive and/or descending facilitatory system overactive. also abnormal dopaminergic system + death of PFC cells
what is the purpose of face and body expression during pain?
changes in posture can be protective (reduce/prevent worse pain). facial expression has no protective function; is communicative, warning those who see it and eliciting help
GABA and glycine act as neurotransmitters on which key postsynaptic channels?
chloride channels. (glycine also helps activate NMDA channels, but you only need a tiny amount)
is keratitis acute or chronic visual loss?
chronic
is uveitis acute or chronic visual loss?
chronic
korsakoff's amnesic state
chronic alcoholism causes korsakoff's syndrome and depletes thiamine, an effect of which can be anterograde (and limited retrograde) amnesia.
fibromyalgia
chronic disorder characterized by widespread musculoskeletal pain, fatigue, and tenderness in localized areas - unknown cause
alzheimer's disease
chronic neurodegenerative disease which accounts for majority of cases of dementia; causes short-term memory loss, confusion, personality changes + loss of bodily functions (leads to death)
which kind(s) of pain are strong opiods not effective at treating?
chronic pain, eg neurological pain
complex regional pain syndrome
chronic systemic disease characterized by severe pain, swelling, and reddening/changes in the skin, affecting an arm/leg or entire body. worsens with time + may not have an obvious nerve lesion
which muscle changes shape of lens?
ciliary muscle
cisterna ambiens
cistern located on the lateral aspect of the midbrain
Class I afferent fibres from muscles/joints are the same as which class of sensory afferent fibres?
clas Aα
aripiprazole
class 3 antipschotic drug. DAD2 partial agonist. 5-HT1A agonist. 5-HT2A (hallucination) antagonist.
treatment for which disease consists of pupil constriction?
closed angle (acute) glaucoma
ventrolateral preoptic nucleus
cluster of neurons in anterior hypothalamus, involved in promoting sleep by *inhibiting the main components of the ascending arousal system
auditory nerve AKA?
cochlear nerve, acoustic nerve
what is the widely agreed best treatment for phobias?
cognitive behavioural therapy. (desensitization)
what is the paradoxical thermoreceptor response?
cold receptors usually increase their firing during cooling below 37oC, but some also respond with a brief AP discharge at high temps (>50oC)
cranial nerve nuclei
collection of neurons in the brain stem that are associated with one or more cranial nerves. sites of origin of motor fibres and termination of sensory fibres of cranial nerves
propriospinal tract
collections of nerve fibers, ascending, descending, crossed and uncrossed, that interconnect various levels of the spinal cord. located in white columns of the spinal cord, surrounding the grey matter
what information is not avaliable in parts of the visual cortex connected to the peripheral retina - but is to parts connected to central retina
colour
amiodarone
common antiarrhythmic, used to treat ventricular and supraventricular arrhymias, usually in acute management
vascular dementia
common form of dementia caused by an impaired supply of blood to the brain, such as may be caused by a series of small strokes
branch retinal vein occlusion
common retinal vascular disease of the elderly, caused by occlusion of one of the branches of central retinal vein
solitary tract
compact bundle that extends longitudinally through posterolateral medulla, surrounded by the nucleus of the solitary tract. descends to the upper cervical segments of the spinal cord. involved in taste, respiratory + cardiovascular system (chemoreceptors)
how does the cerebellum control movement?
compares info developed in the motor cortex (pontine nuclei) with sensory info from spinocerebellar tracts/vestibular system, then sends efferents to *contralateral* thalamus for *motor error correction*
therapeutic index
comparison of the amount of a drug that causes the therapeutic effect to the amount that causes death or toxicity. (higher is safer/more forgiving)
atropine
competitive inhibitor of muscarinic cholinergic receptors, used to decrease parasympathetic effects eg block the vagus suppression of the heartrate
adenosine
compound consisting of adenine combined with ribose, found endogenously and given as medicine to treat arrhythmia involving the AVN. acts on adenosine receptor to open K+ channels
list factors which influence the speed at which inhaled anaesthetics reach the brain
conc in inspired air, rate/depth of breathing, permeability of alveolar capillary membrane, blood flow through lungs, blood/air coefficient, blood flow to brain, partition coefficient between brain&blood of drug
4 examples of insults which can cause amnesia
concussion, chronic alcoholism (korsakoff's), tumours, stroke
heteroporia
condition where relaxed eyes point in different directions, eg a squint, resulting in poor convergence of images in both eyes (causes double vision when drunk)
what is the reciprocal of resistance?
conductance
blocking an ear with cotton wool simulates which kind of deafness?
conductive deafness
the free border of the falx cerebri lies above which cerebral structure
corpus callosum
which structure contains horizontal commissural fibres which unite the two cerebral hemispheres?
corpus callosum
which structure contains the caudate nucleus, putamen and globus pallidus?
corpus striatum
photorefractive keratectomy
corrective laser surgery. uses laser to reshape cornea + increase/decrease amount of refraction possible. not a permanent solution
cruciform axodendritic arrangement
cortical neurons tend to cross MSNs at right angles in such a way that each spiny neuron receives only 1-2 synapses from an individual cortical neuron
corticobulbar tract is aka?
corticonuclear tract
spectral notch
creases in the pinna which are the primary cues for the elevation of a sound
name the sensitive regions within the ampullae of the semicircular canals which can detect movements of endolymph as your head moves
cristae
from their source, do spinothalamic tracts ascend on ipsilateral or contralateral side of the spinal cord
cross when enter spinal cord and ascend contralaterally to thalamus
what colour is healthy CSF
crystal clear
where do the two levels of the dorsal column medial lemniscus pathway supply?
cuneate fasciculus carries info from T6 and above, gracile fasciculus carries info from T7 and below
what do EEG brainwaves look like during a seizure?
cycle of high amplitude, mid-frequency 'spike' followed by a 'slow wave'
fasciculus cuneatus
lateral pathway of dorsal column of spinal cord; carries tactile sensation + vibration + proprioception *from the upper limb* to the *cuneate* nucleus in the medulla
lateral vestbular nucleus is source of which tract?
lateral vestibulospinal tract
corticospinal neurons arise from which layer of neocortex
layer 5
which layer of the primary motor cortex do pyramidal neurons originate in
layer 5
retina
layer of bran tissue back of the eyeball containing cells that are sensitive to light and that trigger nerve impulses that pass via the optic nerve
claustrum
layer of gray matter; linked to consciousness and has connections to all over the neocortex
is wernikes area more dominant on left or right
left
where in the brain is the language area?
left cerebral hemisphere in regions of frontal/parietal/temporal lobes next to the *lateral fissure*
which area of the visual field is viewed by the right hemisphere of the brain?
left visual hemi-field
cataract
lens becomes clouded/yellow so you see a darker, blurry image. more common in elderly. may be due to UV light.
which artery supplies posterior limb of internal capsule
lenticulo-striate arteries
what could cause bi-temporal hemianopia?
lesion at the decussation of optic nerves
why does a wheelchair patient have average BP of around 60-80mmHg?
lesion in cervical spine leads to lack of sympathetic tone
what are the effects of a PICA lesion
lesion leads to *lateral medullary syndrome*; loose pain + temp sensation on ipsilateral side of face and contralateral side of body
cerebellar syndrome
lesions in cerebellar pathways lead to poor error correction in movements - patient shows incoordinated eye movements, speech movements, intention tremor and ataxia (all visible *ipsilateral* to lesion)
which absorbs faster, more or less soluble anaesthetics? why?
less soluble, because less soluble agents like NO2 have a higher MAC so it is safe to deliver more into the lungs faster
spinothalamic tract decussate at the medulla or the level of spinal cord?
level of spinal cord
Type II sensory fibres function
lie within muscle and fire *when muscle is static*
reye's syndrome
life-threatening metabolic disorder in children, of uncertain cause but linked to recenet acute virus (influenza/varicella) and aspirin. causes rash, vomit, fatty liver and encephalitis
HM could form fairly good memories of pictures he'd seen. why?
likely because he still had about 2cm of perirhinal cortex left
activity of which brain system correlates to rated pain intensity reported in chronic pain?
limbic system
what and where is there (more) pooling of photoreceptor signals?
linking up of signals from rods and cones to increase signal strength (at the cost of lower resolution).
why is white matter darker than grey matter on CT scan?
lipid containing material is radiolucent (transparent to x-rays)
what single feature is common to all anaesthetics
lipid solubility
kinocilium
literally a long 'eyelash' found on the apex of inner ear hair cells; plays role in opening K+ channels on sterocilia and detecting body movements
supplementary motor cortex
located anterior to primary motor cortex leg representation. projects to spinal cord and becomes active bilaterally when you simply *think* about moving.
calcarine sulcus
located at the caudal end of the medial brain surface. important because it has visual function (peripheral vision at its anterior end, central vision at its posterior end)
fusiform face area
located in the fusiform gyrus (Brodmann area 37). becomes more active when looking at faces; helps you identify people by face. active on in both hemispheres but the R side is most damaging to lose
in which part of the night is your deepest sleep?
early in the night, within first couple hours of sleep
ectopic foci
ectopic pacemaker; regions outside the SAN which start acting as pacemakers, often causing problems
damage to which parts of the diencephalon disrupt memory?
either *anterior* or *dorsomedial* nuclei of the thalamus, or the *mammillary bodies* of the hypothalamus
what are the indications for angiography
either diagnostic: rupture/haemorrhage or occlusion/ischaemia. or therapeutic uses: modified interventional catheters
what does 'fasciculation' mean?
either: being arranged in bundles (fascicles) OR spontaneous ripple like contraction of muscle beneath the skin, due to lower motoneuron damage
who would you expect listeria monocytogenes to cause meningitis in?
elderly (>55 yrs), pregnant, neonates, or immunosuppressed
resting potential
electrical potential of a cell (relative to its surroundings) when not involved in passage of an impulse
lhermitte's sign
electrical sensation that runs down the back and into the limbs upon neck flexion. linked to several conditions, classically MS
EEG
electroencephalogram: use 21 scalp macroelectrodes to produce a graphical record of electrical activity of the brain
EOG
electrooculograph. electrodes placed above/around eye are used for measuring resting potential of the retina in ophthalmological diagnosis and in recording eye movements
how can we learn about the function of extra striate cortex?
electrophysiological studies on animals/patients. anatomy and histology, tracer studies etc. imaging studies (fMRI, PET, etc.) patient case histories accompanied by imaging studies or post mortem histology
why are strokes in striate arteries common?
emboli carried up the carotid tend to sweep into the MCA and be trapped in the striate artery branch point of the sylvian fissure
what is the main treatment for AVM
embolisation (cutting off the blood supply with coils or glue) + surgery
why do we need seperate efferents to intrafusal (gamma) and extrafusal (alpha) muscle fibres?
enables tightening intrafusal fibres a bit more than extrafusal fibres - advantageous as it puts spindle in a more dynamic range (useful for very fine movements)
which key molecules are responsible for much of the bodies 'toning down pain' responses
endogenous opiate peptides
enkephalin and dynorphin are examples of what
endogenous opiod neurotransmitters (involved in endogenous descending pain modulation)
neurosteroid
endogenous or exogenous steroids that rapidly alter neuronal excitability through cell surface receptors. some have potential as treatment for epilepsy/anaesthetics
which are the first muscles to be noticeably affected by parkinsons disease?
facial muscles
which lense corrects hyperopia?
farsightedness can be corrected with convex lenses
saccade
fast, simultaneous movements of both eyes in the same direction. can be under voluntary control
will a base with lower pKa have a faster or slower onset? why?
faster onset - lower pKa means a greater fraction of molecules exist in the uncharged form, so more can cross the lipid membrane of nerves at a time
is meningioma more common in males or females?
females
name the processes which shoot dynamically in and out of axon growth cones, detecting chemicals which direct axon to its target?
filopodia
damage to the corticospinal tract doesn't actually prevent most movements (other tracts can take over) EXCEPT FOR WHAT?
fine movements, eg of the hands
microneuronography
fine tungsten needle electrode is inserted through skin into peripheral nerve, and connected to a high gain recording amplifier
Broca
first scientist to discover that there are parts of the brain specialised in different functions; found and named an area involved in language
at which end of the cochlear is the basilar membrane fixed, and which end is it free to move?
fixed at the base of cochlear, free to move at the apex
which are found nearer the central canal, the motor neurons of flexor or extensor muscles?
flexor
syrinx
fluid-filled cavity which forms in the central spinal cord (usually cervical spine)
why is blue light often used to examine front of eye?
fluorescein dye will be uptaken by any breaches/abrasions in corneal epithelium - this orange dye reacts to blue light.
refractive power (of the eye) = reciprocal of what?
focal distance
what are the 'plaques' in MS
focal lesion where myelin sheaths gets lost, and brain attempts to remylinate (but fails). an oedema or buid up of astrocytes may also form due to surrounding neuron destruction
which brain area(s) are most involved in classical conditioning?
for conditioning involving emotional responses, the amygdala. if involving skeletal musculature, is the cerebellum.
name the foramen directly below superior orbital fissure
foramen rotundum
is the thalamus in forebrain or midbrain?
forebrain
prosencephalon
forebrain; develops from anterior neural tube. forms telencephalon and diencephalon
frontal eye fields
found at bottom of middle frontal gyrus. responsible for non-tracking, voluntary movements of the eye
where is the one part of the retina where cones outnumber rods?
fovea
which area has the highest density of cones in the eye?
fovea
what does frequency and amplitude of a light wave determine?
frequency determines hue, amplitude determines brightness
what does '20/20 vision' mean?
from 20ft away, you can read up to the designated '20 foot' line of letters on a snellen chart. (eg worse vision would be 20/50, better vision 20/10)
how might tinnitus originate from within the body?
from a blood vessel near the ear having abnormally fast/turbulent blood flow (think atherosclerosis, anemia, pregnancy)
how does the basilar membrane change along its length?
from base to the apex of cochlea: becomes wider, less stiff, heavier, measures lower sounds
where does the internal carotid arise?
from common carotid in the neck, at around C4/chin height
where do microglia cells originate?
from perivascular space or monocytes
Spino-parabrachial pathway carries fibres from where to where? what is itsgl function?
from the spine to parabrachial nuclei of the brain, to respond to nociceptive inputs
where do the vertebral arteries arise
from the subclavian arteries, posterior in the root of the neck
how is the basilar artery formed?
from the two vertebral arteries joining
are you likely to have huntingtons earlier if you inherit it from your mum or your dad?
from your dad
primary motox cortex is in which lobe?
frontal
beta rhythms are particularly seen in which regions of the brain?
frontal and parietal
motor neuron disease is often linked to which form of dementia?
fronto-temporal lobe dementia
what part of the eye does the opthalmoscope illuminate?
fundus (the back of the eye, including retina, optic disc, macula, fovea)
what is the far point of your vision
furthest point at which you are able to bring an object into clear focus (for healthy eyes, this is *infinity*
efferent innervation to muscle spindles is carried by which fibre type?
gamma motor neurons
which are the only cells in the retina to produce action potentials?
ganglion cells
mamillary body is important for?
generating new memory (depletes in people with thiamine deficiency eg alcoholics)
drosophilia
genus of small flies, often called fruit flies
how do meningitis bacteria infect their way into subarachnoid space?
get through nasal mucosa, into bloodsteam, and through blood brain barrier into subarachnoid space where they multiple rapidly
Betz cells
giant pyramidal cells located within primary motor cortex, that give rise to *corticospinal tract*
which scale assesses the degree of coma?
glasgow coma scale
what are the 3 main responses measured in the GCS?
glasgow coma scale measures: eye opening response, verbal response, motor/pain response
oligodendrocyte
glial cell similar to an astrocyte but with fewer protuberances, concerned with the production of myelin in the CNS
satellite glial cells
glial cells that cover the surface of nerve cell bodies in sensory, sympathetic and parasympathetic ganglia. supply nutrients, protection, and control over the microenvironment of the ganglia (similar role to astrocytes in CNS)
proliferation of glial cells is called
gliosis
what is the main output nucleus of the basal ganglia? where do these fibres go?
globus pallidus, inhibitory fibres to the thalamus
cone cells always have which neurotransmitter?
glutamate
is cortical drive into basal ganglia glutamate or gaba?
glutamate
what is the most abundant neurotransmitter in the nervous system?
glutamate
what is GAD
glutamate decarboxylase. enzyme which converts glutamate to GABA in a single step
GTN
glyceryl trinitrate: explosive yellow liquid in dynamite and also medicine as a vasodilator in the treatment of angina pectoris
which stain is best used to view neurons?
golgi stain (can see individual cells not just pink+purple mass)
diffuse astrocytoma
grade II brain tumour originating in astrocytes; tends to invade surrounding tissue and grow at a relatively slow pace
schild plot
graph constructed from dose-effect curves and dose-ratios which can be used to work out the PA2 of a competitive antagonist
concentration-response curve
graph showing how increasing the concentration of a substance (drug?) affects a functional response of a tissue; aka dose-response curve
audiogram
graph that shows the audible threshold for an individual as measured by an audiometer (hearing test machine).
how does hippocampal amnesia affect ability to imagine new experiences?
greatly reduces the richness/detail of imaginations compared to normal people. (to do with poor episodic memory. same areas involved in remembering past also involved in imagining future; you need to remember the past to do this)
is cerebral cortex white or grey matter?
grey
is the cerebellar cortex made of white or grey matter?
grey
is the thalamus comprised of white or grey matter?
grey
which contains more synaptic networks, grey or white matter?
grey (white matter structures are devoid of synaptic networks)
parahippocampal gyrus
grey matter cortical region of the brain that surrounds the hippocampus, important in memory encoding and retrieval
how can you instantly tell which way 'up' a transverse section of spinal cord is?
grey matter is always fatter *anteriorly*
periaqueductal grey
grey matter located around the cerebral aqueduct within the midbrain. forms the primary descending analgesic pathway from cerebral cortex (has enkephalin-producing cells that suppress pain)
name the cells which fire action potentials when an animal passes through a specific small region of space
grid cells and place cells
ventral medial fissure
groove along midline of anterior surface of spinal cord + medulla
lymphoma
group of blood cell tumors that develop from lymphatic cells; usually malignant. Relatively treatable
clarke's column
group of interneurons found in the medial part of Lamina VII of the spinal cord, mainly from T1 to L3 levels. important for proprioception (transmits spinocerebellar tracts)
clarkes column
group of interneurons found in the medial part of Lamina VII of the spinal cord. It is mainly located from the T1 to L3-L4 levels and is an important structure for proprioception
nucleus basalis of Meynert
group of neurons below globus pallidus in basal forebrain. has wide projections to the neocortex/fornix. involved in vision perception, ACh + intelligence/learning
where are more neurons - gut or spinal cord?
gut
gyri VS sulci
gyri are the bulges and sulci the furrows between them
what kind of hair cells are found in the organ of corti?
hair cells; 3 rows outer hair cells (notably sensitive to damage) and 1 row inner (release NT onto auditory nerve fibres)
difference between hallucination and delusion
hallucination is an experience of perceiving/sensing something that is not present. delusion is a fixed false belief which the person believes despite all evidence
mescaline
hallucinogenic and intoxicating compound present in mescal buttons from the peyote cactus
which general anaesthetic causes liver damage
halothane
function of the auditory canal
has wax to protect from insects and hairs to keep a constant temperature. also serves to amplify sounds around its resonant frequency (2,000-5,000 Hz)
ototoxic
having a toxic effect on the ear/ its nerve supply
the anterior limb of internal capsule divides which structures?
head of caudate nucleus and putamen/globus pallidus
the superior and inferior colliculi contain reflex centres involved in what?
hearing and vision (they used to be the main hearing/vision centres until cerebrum evolved into a higher system)
cochlear implant
hearing device which replicates "frequency-to-place" mapping of basilar membrane, replacing hair cells by stimulating the auditory nerve at different frequencies
why might tinnitis onset with hearing loss?
hearing loss can lead to phantom sounds, indicating that tinitis may be caused by reduction of auditory input, not cochlear damage.
Rinne's test
hearing test, evaluates loss of conductive hearing in external/middle ear. compares perception of sounds transmitted by air to those transmitted by bone through the mastoid. negative (abnormal) response: bone conduction heard longer than air
name the 4 pharmacological target organs of antihypertensive drugs
heart, vasculature, autonomic nervous system, and kidneys
difference between hemispatial neglect and homonymous hemianopia
hemianopia is a lesion earlier in the visual pathway - you don't *see* half the visual field. hemispatial neglect is more cognitive - you can see everywhere but just *ignore* half
transtentorial herniation
herniation of the medial temporal lobe from the middle into the posterior fossa, across the tentorial opening; compresses oculomotor nerve on same side
dendritic eye lesions on surface of cornea are characteristic of which disease?
herpes simplex keratitis
strabismus is AKA
heteroporia
do inner hair cells produce a DC response at high or low frequencies?
high
how is the glasgow coma scale scored?
higher score = greater responses. score of <8: coma, 9-12: moderate head injury, >12 mild head injury (max score is 15)
where is the huntingtons gene located?
highest tip of chromosome 4
rhombencephalon
hindbrain; develops from neural tube. forms metencephalon and myelencephalon
which structure in the brain is classically associated with the *formation of new* memories?
hippocampus
brodmann area 28 provides the principal excitatory drive for which brain area?
hippocampus (area 28 = ventral entorhinal cortex)
which 2 brain structures are affected first in alzheimers disease?
hippocampus and posterior parieto-temporal cortex
which is more associated with conditioning and which with declarative knowledge, hippocampus or amygdala?
hippocampus with declarative knowledge, amygdala with conditioning.
where in the brain do neurofibrillary tangles form initially? where do they progress to?
hippocampus/entorhinal cortex at first, progressing to limbic system before then affecting the rest of the brain
spatial memory is particularly located in which part of the brain?
hippocampus; it has 'place cells' which encode location in the environment
post-stimulus time histogram
histograms of the times at which neurons fire. used to visualize the rate and timing of neuronal spike discharges in relation to an external stimulus. different nerve cells have different PSTHs
3 categories of OCD
hoarders/collectors, ritual checking behaviour, cleanliness
what travels through the transverse foramina?
holes in the transverse processes; give passage to the *vertebral artery, vein and sympathetic nerves*
uncus
hook-shaped process or part; particularly the anterior extremity of the Parahippocampal gyrus: part of the limbic system involved in olfaction
which cells pre-process information from rods and cones before sending it to the optic nerve?
horizontal, bipolar, amacrine and ganglion cells (retinal interneurones)
what is HRP
horseradish peroxidase. enzyme which can be used to label single cells, eg neurons in their entirity
treatments for dry eyes
hot compress + lid cleaning - stimulates oil production/good quality tears
how do you treat blepharitis
hot compresses and scrub base of eyelid with damp cotton buds
what is a key function of periaquital grey
houses a descending analgesic pathway, involving enkephalin-producing cells that suppress pain by releasing endogenous opiods
describe the dendrites of purkinje cell
huge dendritic tree which is very spead out but completely flat (like your fingers branching from your hand)
Natalizumab
humanized monoclonal antibody against the cell adhesion molecule α4-integrin, used to treat MS and Crohn's disease. prevents rolling/binding of immune cells to vessel wall in intestines and BBB, so they are less able to enter gut lining/CSF
describe what you might expect to see if you clinically examined the gait of someone with parkinsons
hunched over, sway side to side, small shuffling steps, difficulty starting and difficulty stopping once moving
which proteins aggregate in huntingtons disease?
huntingtin
enlarged lateral and 3rd ventricles, without enlarged 4th ventricle, suggests what?
hydrocephalus caused by an obstruction between 3rd and 4th ventricle - perhaps cerebral aquaduct
do anaesthetics bind to hydrophilic or hydrophobic domains of proteins?
hydrophobic
what are the adrenal gland causes of 2ndary hypertension?
hypermineralcorticoidism, hyperglucocorticoidism, phaeochromocytoma
do lower motoneuron lesions lead to hyper or hyporeflexia?
hypo
are dark structures on a CT hyper or hypodense
hypodense
which DA pathway is related to the negative symptoms of shizophrenia
hypofunction of mesocortical pathway
adverse effects common to all class I antiarrhythmic agents
hypotension, nausea, vomiting
which part of the brain can inhibit normal baroceptor reflexes during 'fight or flight' ?
hypothalamus
which part of the diencephalon is involved in the autonomic NS, limbic system, and neuroendrocrine system?
hypothalamus
which higher centres (in the brain) are involved in autonomic control?
hypothalamus, forebain, amygdala, hippocampus etc
what is the key area for coordinating autonomic nervous system responses in the brain? how?
hypothalamus. it projects to key ANS areas eg the NTS, the parasympathetic nuclei in the medulla, the rostroventral lateral medulla and preganglionic sympathetic neurons in the spinal cord
the monoamine hypothesis of depression
hypothesis that "depression is a deficit of monoamine transmission, and antidepressents stop monoamine transmission"
standard consolidation theory
idea that Hippocampus + related MTL structures are initially required for episodic memory storage and retrieval, but after time, these areas are less involved and cortex is able to retrieve memory without hippocampal help
multiple trace theory
idea that although connections to the cortex grow with time, hippocampus mediates storage + retreival of episodic memories for entire life, not just before the memories have been consolidated
in memory, how might the sight and smell of a rose become linked?
if a neuron receives input for both the smell and sight of a rose (often activated *together*) and these inputs *summate* to activate the neurone and create an LTP
astigmatic fan
if any lines look blacker than the rest - and the blackest lines change as you rotate your head around an anterior-posterior axis - indicates astigmatism
does paired stimulation of parallel fibres and climbing fibres on purkinje cells lead to long term *depression* or *potentiation* and why?
if both are active, climbing fibre increases Ca levels in purkinje cell, and parallel fibre increases protein kinase C. together, these react to phosphorylate AMPA receptors which *in purkinje cells only* decreases AMPA receptors
how can a weak input undergo long term potentiation?
if it coincides with postsynaptic depolarization caused by a strong input, or another weak input which summates. (this makes the LTP *associative*)
the axon reflex
if stimulation onto skin is so severe as to damage skin, this is fed back by collateral nerves which release substance P - causes mast cells to release vasodilatory and inflammatory peptides around the site
why does boosting the amplitude of sound vibrations in the ear result in narrower tuning?
if theres a higher amplitude in response to same sound, there is a narrower peak, resulting in narrower tuning
why might you get *referred* phantom limbs?
if you lose a hand for example, the next areas on the homunculus may branch to where the hand used to be 'felt' in the somatosensory cortex
which drug is regarded as the gold standard in terms of efficacy in antidepressants?
imipramine (a TCA)
when does inflammation occur in the absence of infection?
immune disorders, atherosclerosis, trauma, ischaemia
associative visual agnosia
impairment in recognition or assigning meaning to a stimulus that is accurately perceived. patients can copy drawings but not identify objects they've drawn. not associated with a generalized deficit in intelligence, memory, language or attention
functions of middle ear
impedance matching, selective oval window stimulation, pressure equalisation. transfer sound from air (tympanic membrane) to fluid (oval window)
why is the internal capsule clinically revelant?
important site of stroke (subsequently called a capsular stroke). all descending motor fibres pass through posterior limb of internal capsule
what are the aims of pain treatment
improve control of pain, reduce disabling effects with short + long term goals, build a realistic model of problem to reduce catastrophising, aid friends and family
descartes
in 1600s came up with idea of 'dualism' - that the mind and the brain depend on each other, but are separate.
difference between bipolar and unipolar EEG recording
in bipolar, the voltage difference between a pair of electrodes is measured. In the unipolar, the potential of each electrode is compared either to a neutral electrode or to the mean voltage of all electrodes
give 2 conditions in which pupil healthily dilates
in dark (raising sensitivity) and in excitement (sympathetic system)
why do demyelinated plaques tend to look darker than healthy grey matter?
in healthy grey matter, there are still myelinated neurons projecting through it from the white matter
do on center bipolar cells depolarise or hyperpolarise in light? how about in dark?
in light, they depolarise, in dark, they hyperpolarise
why can you see colours better in brighter light?
in low light, only rods are sensitive enouge to see with; cones won't fire hence can't see colours
why does the volume ratio of white to grey matter change at different spinal cord levels?
in lower regions there is more grey matter and less white, because there are fewer ascending/descending tracts
where is visual cortex located
in occipital lobe, mostly medial hemisphere above and below the *calcarine sulcus*
how do EEGs differ when neurons are firing irregularly or in sync?
in sync has larger amplitudes and slower frequencies - like when asleep
where is auditory cortex located
in temporal lobe, beneath and parallel to lateral fissure in the *superior temporal gyrus*
where does the dorsal-column medial lemniscus pathway decussate?
in the medial lemniscus tract (between the dorsal column nuclei and the thalamus) at around the level of the medulla
in which part of the CNS does the corticospinal tract break up into many bundles (rather than one bundle on each side)
in the pons
where are most of the proteins made in a neuron?
in the soma (processing centre)
why is there increased risk of overdose if a heroin user takes heroin in an unfamiliar environment
in their normal setting, the user has their normal tolerance. in new settings, they may have no such tolerance
constructional apraxia
inability or difficulty to build, assemble, or draw objects
anterograde amnesia
inability to *make or retrieve* new memories *after* the trauma
anhedonia
inability to feel pleasure
agnosia
inability to recognize/perceive objects by use of the senses, due to brain damage in tempoparietal cortex
augment
increase
do antidepressants increase or decrease neurogenesis in hippocampus
increase
does angiotensin increase or decrease BP?
increase (by vasoconstriction and fluid retention)
what is the effect of nitrous oxide and ketamine on sympathetic outflow?
increase it
class II antiarrhythmic agents
increase the period of the pacemaker cycle by antagonising Beta sympathetic activity. this group includes beta blockers
hyperalgesia
increased sensitivity/reactivity to *painful* stimuli, which may be caused by damage to nociceptors or peripheral nerves, or temporarily by sickness/stress
describe how urine storage requires both autonomic NS and somatic motor NS?
increased sympathetic activity inhibits parasympathetic contraction of the bladder smooth muscle (the detrusor) - enables bladder to expand. simultaneously, sympathetics + somatomotors increase bladder neck contraction + skeletal muscle of urethral sphincter respectively - maintains continence.
does D2 antagonism increase or decrease prolactin levels
increases (tuberoinfundibular pathway)
why does parkinsons treatment often induce new addictive behaviours?
increases dopamine in mesolimbic/nucleus accumbens/ventral tegmental area (involved in reward system)
what happens to the human sleep/wake cycle if environmental cues (light/temp etc) are removed?
increases from 24 hr cycle to up to 36hr cycle (physiological functions may not keep in step though)
3 functions of dopamine in the brain
increases motor aspects of basal ganglia, activates euphonia + cognition of brain, and inhibits prolactin release
why is catastrophising so detrimental to pain recovery?
increases pain intensity, predicts chronicity and disability developing from acute pain, and predicts mood/behaviours in chronic pain
does digoxin increase or decrease the heart?
increases strength of contraction but decreases AV conduction rate
why is a bit of anxiety good for you?
increases vigilance
when inhaling anaesthetics, which increases rate of equilibrium - increasing or decreasing rate+depth of respiration? why?
increasing. it increases rate of equilibration between alveoli and blood
which passes through the globus pallidus externa, the direct or indirect pathway?
indirect
which basal ganglia pathway degenerates faster in huntingtons disease?
indirect (hence you struggle to *inhibit unwanted movements*)
which colliculus do almost all ascending auditory pathways go through?
inferior colliculus (integration centre)
which cerebellar peduncle contains fibres from the spinocerebellar tract? what do they carry?
inferior peduncle. carry info from joints and muscles to cerebellum
keratitis
inflammation of the cornea causing watery painful eyes and blurred vision
blepharitis
inflammation of the eyelids caused by chronic staphylococcal inflammation; characterized by redness, burning, itchiness blurring, swelling and dried crusts/oily secretions on lids
optic neuritis
inflammation of the optic nerve. causes painful loss of vision
uveitis
inflammation of the uvea, the middle, pigmented, vascula layer of eye (including choroid/iris/ciliary body). causes painful visual loss
two main types of pain
inflammatory and neuropathic
what is memory priming?
influencing what thoughts you withdraw from their memories in a non-conscious way by what has happened to you recently - eg product placement.
What type of sensory information does the spinothalamic tract carry ?
info about pain, temperature (lateral pathway) itch and crude touch (anterior pathway)
two main categories of general anaesthetics
inhalation agents (vapour or gas), and intravenous agents
aside from intravenous agents, general anaesthetics can be administered as what?
inhalation agents, which are either *gases* or *volatile liquids*
does glutamate inhibit or stimulate on-centre bipolar cells?
inhibit (hence they fire more in the light)
how do opiates release pleasure in the brain?
inhibit GABA inhibitory neurons connected to dopaminergic neurons in nucleus accumbens - disinhibition
how do ACE inhibitors decrease blood pressure?
inhibit the pulmonary conversion of angiotensin I to angiotensin II, hence reduce the vasconstrictive a ects of angiotensin II. also decrease the resorption of Na+ & water in PCT
in general, do activated alpha and beta 2 receptors have excitatory or inhibitory effects?
inhibitary
in stretch reflex, which muscles *aside from the homonymous muscle* may also be affected?
inhibitory GABAergic neuron can project to *antagonist muscle* to block it. other motoneuron may project to *synergist muscle*
renshaw cell
inhibitory interneurons found in the gray matter of the spinal cord. provide a regulatory feedback system to prevent rapid repeat firing of motor neurons
what is IPSP
inhibitory post-synaptic potential. synaptic potential that makes a postsynaptic neuron less likely to generate an action potential, due to postsynaptic influx of anions causing hyperpolarisation
anti VEGF injections
injected drugs which reduce new blood vessel growth or oedema (swelling), often used in wet age-related macular degeneration/eye conditions which cause fluid to leak under the retina
what is the only example of where drugs acting on the CNS can be *given locally*
injecting morphine straight into spinal cord to target its receptors
which ear hair cells function to transmit info to the brain via auditory nerve?
inner hair cells
are the hair cells in the organ of corti passive or active?
inner hair cells are *passive* and outer hair cells are *active*
how do IHCs perform *mechano-electrical transduction*
inner hair cells, in response to basilar membrane vibration, release neurotransmitter onto synapses of auditory nerve fibres
long term depression
input-specific reduction in the strength of neuronal synapses lasting following a long low frequency tetanus. (low Ca2+ levels in postsynaptic neuron decreases AMPA receptors)
corticopinal pathway has inputs onto which neurons in the stretch reflex?
inputs the Ia inhibitory interneuron, and the motoneurons to the homonymous muscle
aneurysm coiling
inserting a coil into aneurysm via catheter. fills the aneurysm with coils so that blood can't enter it - prevents it growing or rupturing
hypnotic drugs are used to treat which condition?
insomnia (hypnosis is greek for sleep)
non-associative learning
instances in which an animal's behaviour toward a stimulus changes in the absence of any apparent associated stimulus or event (such as a reward or punishment)
insula
insular cortex is a portion of the cerebral cortex in each hemisphere, folded deep within the lateral sulcus. has somatosensory + taste area. middle cerebral artery runs through here
amyloid precursor protein
integral membrane protein expressed in many tissues and concentrated in the synapses of neurons. can cause protein deposits if excessively cleaved by secretases
what are the ideal psychological models of pain
integrated biopsychosocial models
neuralgia
intense, typically intermittent pain along the course of a nerve, usually caused by central/ peripheral neuronal injury
the sclera is continuous with what?
interiorly with the choroid, externally with the dura of the CNS, anteriorly with the cornea
cauda equina compression
intervertebral disc prolapse/tumour compresses cauda equina. damages important nerves like S2,3,4 - causes bladder, anus and erectile dysfunctions
intracranial space occupying lesions
intracranial lesion usually due to malignancy (though can be caused by an abscess or haematoma). resulting raised ICP can cause internal herniation
which causes more rapid general anaesthesia, inhaled or intravenous agents?
intravenous (causes unconsciousness in about 20s - as soon as drug reaches brain - rather than a few minutes)
difference between intrinsic and extrinsic lesions of nervous system
intrinsic are within nervous system, extrinsic lie outside and compress the nervous system. extrinsic lesions are more likely to be remediable by neurosurgery
brudzinskis sign
involuntary flexion of the hips in response to passive flexion of the neck; indicative of meningeal irritation
what is the time difference between transmission with ionotropic + metabotropic receptors?
ionotropic is rapid <<1ms, whereas metabotropic much slower: >50ms
what are monovalent cations
ions with a charge of +1, eg Na+ and K+
is the vestibulospinal tract ipsilateral or contralateral
ipsilateral
are lower moto neuron lesion effects ipsilateral or contralateral to the lesion?
ipsilateral (lower motoneurons innervate muscles on same side as their cell bodies)
dorsal spinocerebellar tract
ipsilateral tract involving two neurons which conveys proprioceptive information from skeletal muscles to the cerebellum, via Clarkes column
does the cerebellum coordinate movements on the ipsilateral or contralateral side of the body?
ipsilateral. its efferents decussate on way to motox cortex, and fibres from the cortex (eg corticospinal tract) decussate again, back onto same side.
agoraphobia
irrational fear of crowded spaces or enclosed public places
catastrophizing
irrational thought a lot of us have in believing that something is far worse than it actually is
iproniazid
irreversible nonselective MAO inhibitor
disadvantages of propofol
irritant at site of injection
can neuropathic pain be treated?
it can be poorly controlled by drugs like tricyclic antidepressants/ gabapentin/pregabalin, with disabling side affects such as confusion
does the enteric nervous system work in isolation from the CNS?
it can, but it gets many inputs from autonomic NS etc which may override it - symp decreases and parasymp increases enteric activity
how does light affect neurotransmitter release from photoreceptors
it decreases glutamate release by *hyperpolarising* them
how can aripiprazole act as an antipschotic when it is a D2 agonist?
it is a *partial* agonist of DAD2 receptors - competitively decreases action of dopamine overall even though it has a small agonist effect itself
why is the cornea the only body part that can be transplanted between people without risk of rejection from new body?
it is avascular, so escapes the immune systems careful watch
how is codeine so weak if its a pro-drug for morphine
it is converted into morphine in the body, but this is usually slow (depending on enzymes you have). codeine itself can't bind to opioid receptors
what are memories made of?
it is widely agreed that they are alterations in synaptic strength, involving long term associations and long term depressions
why might pain prevent you getting opiod addiction?
it may inhibit the reward pathway which would have made you addicted (could help explain why there are few addicts after hospital use)
how does myelin save ATP energy needed in axons?
it prevents the whole axon being influxed with Na+ (during an AP) and needing to be pumped out to 'reset'. instead, this depolarisation + pumping out is only needed at nodes of ranvier
why is prestin important in outer hair cells
it responds to sound by contracting, changing the shape of OHCs to *amplify/sharpen* the soundwave travelling in the basilar membrane (improves audible threshold and distinguishing different frequencies
why is ketamine used as an anaesthetic in those with asthma/COPD and in war zones?
it suppresses breathing much less than other anaesthetics - good in those with previous breathing problems/in places with no ventilator
how can a single neuron contact another neuron more than once?
its axon may have multiple boutons to connect with multiple dendrites
why isn't motor cortex mapping that acurate. why is this a good thing?
its not a simple 1:1 projection - there is overlap + plasticity between areas. means is easier for stroke victims etc to retain some functions around body
hemiballismus
jerky movements of upper limb on contralateral side of body, like throwing a ball. caused by subthalamic nucleus lesion
which other receptors aid the joint
joint receptors, cutaneous receptors, pain endings within the muscle itself
what are the 6 universally recognisable facial expressions?
joy, fear, disgust, sadness, surprise, anger
vagus nerve leaves the skull through which foramen?
jugular foramen
in unipolar EEG recordings, where might you place the macroelectrode to pick up a 'neutral' reference voltage
just behind the ear (there is not much brain below that part of scalp)
which consonant sounds are in the high frequency range of hearing?
k, f,s,th
how do you convert between degrees C and kelvin?
kelvin = celsius + 273
where do unmyelinated axons travel in spinal cord?
kind of anywhere; but most often in the white matter with myelinated axons
cerebellar ataxia
lack of voluntary coordination of muscle movements (eg gait abnormality) caused by cerebellar damage eg tumour/infection/hereditary disorders
decerbrate
lacking cerebral brain function, as by having the cerebrum removed/its blood supply cut off
nissl substance
large granular body found in neurons for protein synthesis. useful for staining (cresyl violet stain) as they are found mainly in cell soma not axons
inferior olivary nuclei
largest nuceli in the olivary body, part of the medulla. major input to cerebellum, providing climbing fibres
short-term memory
lasts for a few minutes, usually involves mental rehearsal and is easily disturbed (e.g. the initial stages of learning a telephone number)
tardive
late-occurring (especially with reference to symptoms of a disease)
what does lateral light and medial music mean?
lateral geniculate nuclei are for vision, medial geniculate nuclei are for auditory
what is the LGN?
lateral geniculate nucleus. small, ovoid, ventral projection at the termination of optic tract on each side of the brain; relay center in the thalamus for the visual pathway
how does occlusion of PICA manifest?
lateral medullary syndrome (due to ischaemia of lat. medulla). sensory deficits in ipsilateral side of face, and contralateral side of body
PICA stroke symptoms are also called what?
lateral medullary syndrome or wallenberg syndrome
dorsal lateral medullary syndrome
lateral part of the medulla oblongata infarcts due to vertebral artery/PICA occlusion. ipsilateral loss of pain/temp from face, and contralateral loss of pain/temp from rest of body. may also have vestibular nucleus damage (vomiting/falling)
korsakoff's syndrome
serious mental illness, typically the result of chronic alcoholism, characterized by disorientation and a tendency to invent explanations to cover a loss of memory (confabulation)
which genes are likely to be affected in heritable depression
several genes of small effect, involved in eg serotonin transporters. environmental factors interact with these
agranulocytosis
severe deficiency of granulocytes in the blood, causing increased vulnerability to infection
craniorachischisis
severe form of neural tube defect in which both the brain and spinal cord remain open to varying degrees. most babies are stillborn
define *malignant* hypertension
severe hypertension with clinical features (e.g. headache, confusion, retinopathy). medical emergency.
corona radiata
sheet of white matter in branching into each hemisphere contains both descending and ascending axons. carries nearly all neural traffic from and to the cerebral cortex. concentrates itself as *internal capsule* deep inside hemisphere
crossed pupil reflex
shining light into *only one eye* will constrict *both* eyes
uses of nitrous oxide
short acting analgesic, carrier gas with stronger anaesthetics, can be used in pregnant women to relieve pain
class IV antiarrhythmic agents
shorten the plateau phase of cardiac action potential by blocking calcium channel blockers; slows AVN conduction.
flashing a light into one eye will contract one or both pupils?
should contract both (failure of either eye indicates lesions in the pupillary reflex pathway
how does the overall appearance of the brain change in alzheimers disease?
shrinkage of the forebrain + expansion of the sulci and ventricles as the brain tissue is lost
in brown-sequard syndrome, which side do you lose sense of proprioception on and why?
side ipsilateral to the lesion - because the dorsal column (carries proprioception) ascends ipsilaterally, whereas spinothalamic ascends contralaterally
striatum is said to be involved in what type of memory?
skills and habits (part of implicit memory)
glabrous skin
skin devoid of hair
acne rosacea
skin disease of adults (more often women) in which blood vessels of the face enlarge resulting in a flushed appearance
cutaneous mechanoreceptors
skin receptors which respond to mechanical stimuli from physical interaction eg pressure and vibration. Are all innervated by Aβ fibers, except the mechanorecepting free nerve endings, which are Aδ
mechanism of action of N2O?
slightly blocks NMDA (causes dopamine release/euphoria) and β2-subunit-containing nACh channels. weakly inhibits AMPA, kainate, GABAC, and 5-HT3 receptors. slightly potentiates GABA-A (anxiolytic) and glycine receptors. releases endogenous opioid peptides (analgesic). may act to imitate NO in CNS.
ruffini endings
slow adapting deep mechanoreceptor in the subcutaneous tissue of humans. have large receptive fields to detect stretch eg at joints.
bradykinesia
slow initiation of voluntary movement eg in parkinsons
class I antiarrhythmic agents
slow the depolarisation phase using sodium channel blockers (inhibits action potential propagation). Ia are medium speed, Ib fast, Ic slow
class III antiarrhythmic agents
slow the repolarisation phase + increase refractory period
C fibres respond to which kind of pain?
slow, burning pain
difference between slowly adapting and rapidly adapting cutaneous mechanoreceptors
slowly adapting (SA) receptor endings signal prolonged skin contact, whereas RA receptors signal swift changes/vibrations only
which has higher input resistance, small or large motor units?
small
which depolarises first, small motoneurons or large motoneurons?
small (the recruitment principle)
demyelinated plaque
small areas of CNS suffering from demyelination, most commonly seen in MS
flocculus
small lobe of anterior cerebellum key in vestibulo-ocular reflex
dendritic spine
small membranous protrusion from a neuron's dendrite that typically receives (excitatory) input from a singlesynapse of an axon
which are more sensitive to small forces, golgi tendon organs on large motor units, or on a small motor unit?
small motor unit
chalazion
small painless sebaceous cyst of the eyelid resulting when a Meibomian gland is blocked
rostroventral lateral medulla
small region of brainstem, key in controlling BP; projects to the sympathetic preganglionic neurons in the spinal cord to excite sympathetic activity in heart + vessels
parvocellular ganglion cells
small retinal ganglion cells which respond to single cones/groups of same cones (hence colour sensitive). form 90% of retinal ganglion cell population
papilla
small rounded protuberance on a part or organ of the body
where/what are the dorsal column nuclei seen on the medulla?
small swellings either side of posterior midline, due to sensory relay nuclei transferring input from spinal cord to thalamus
drusen
small yellowish hyaline deposits that develop beneath the retinal pigment epithelium, sometimes appearing as nodules within the optic nerve head. most often in over 60s. associated with age-related macular degeneration.
difference between sensory and somatosensory
somatosensory refers specifically to touch, temp, proprioception and pain (eg not sight/hearing)
do presynaptic sympathetic neurons synapse in paravertebral ganglia at the same level as they emerge?
some do, other axons travel up/down the sympathetic chains to synapse at a different level
how does CSF travel down the spinal cord?
some flows into central canal, but most travels in the spinal subarachnoid space
cerebellar granule cell
some of smallest and most numerous neurons in brain. found in cerebellum, they travel from internal to external cortex, where they bifurcate into parallel fibres which form hundreds of synapses with purkinje cells
what is the most problematic effect of ECT?
some retrograde amnesia (hence it is only applied unilaterally to reduce this)
what do different subunits of voltage gated sodium channels do
some units which cross membrane, some units which detect membrane voltage, some units which form the pore, some units which can block/open the pore
what does contraction of the ciliary muscle do?
sort of 'pushes into' the eye, releiving tension of zonule fibres to allow the lens to become globular
allocentric space
space/movements centred in people or places other than oneself
difference between temporal and spacial summation
spacial = way of achieving an AP in a neuron with input from multiple presynaptic cells. temporal = by a single neuron using high frequency to amplify depolarisation + achieve an AP.
cajal
spanish neuroscientist who made detailed drawings of neurons in the brain, and began hypothesising that information is stored by modifying connection
tonotopy
spatial arrangement of where sounds of different frequency are processed in the brain. Tones close in frequency are represented in neighbouring regions
what is FLAIR
special MRI substance with long T1 to remove effects of fluid from images; useful for periventricular region close to CSF, eg infarction/MS/subarachnoid haemorrhage
photoreceptor cell
specialised type of neuron containing proteins which absorb photons, triggering change in cells membrane potential. include rods, cones + photosensitive retinal ganglion cells
axon hillock
specialized part of the cell body of a neuron that connects to the axon
what is the main function of the cortical region between the ascending and anterior rami of the lateral fissure?
speech production (broca's area)
foramen rotundum is a round hole in which bone?
sphenoid
which muscle changes size of pupil?
sphincter pupillae and dilator pupillae
which structure in medulla corresponds to the superficial dorsal horn of spinal cord?
spinal nucleus of trigeminal nerve
how do current motivation and state affect how pain is perceived?
spine-brain loops (forming the brain's 'conversation' with the spinal cord) use info like motivation and state (eg needing to move injured arm to eat/drink) to control descending modulation of pain signal
the cerebellum receives afferent connections from which 3 systems to co-ordinate movements?
spinocerebellar tracts (sensory info from joints/muscles), vestibular system, and motor cortex
what is the difference between the type of touch sensed by the spinothalamic and dorsal column pathways?
spinothalamic carries info of coarse touch and pressure. dorsal column carries info of discriminative (fine) touch
which afferent spinal tract enables nociception?
spinothalamic tract (delivers info from c fibres etc up to the thalamus)
what are the causes of trigeminal neuralgia?
squashing of trigeminal nerve root by superior cerebellar artery. shingles (post herpetic neuralgia)
what are the stages of anaesthesia?
stage I: analgesia, still conscious. II: excitement + delirium (think ethanol!), irregular respiration. III: surgical anaesthesia - unconscious, depressed resp+reflexes. IV: *overdose*. medullary depression - no spontaneous respiration, coma + death follow
what are the stages of sleep
stages 1-4 (from REM to stage 4), then 4-1, repeating in cycles around 6 times a night
stye
staphylococcus aureus infection of sebaceous/sweat glands on/below the eyelids causing a small painful red bump of water/pus.
give the 2 causative agents you would expect in a case of neurosurgical meningitis
staphylococcus aureus, gram negative bacteria including Psudomonas aeruginosa
amyloid
starchlike protein that is deposited in the liver, kidneys, spleen, or other tissues in certain diseases
describe the major loop of signal flow through hippocampus
starts in entorhinal cortex, projects to dentate gyrus. granule cells from there send mossy fibres to CA3. pyramidal cells from there run to CA1, and pyramidal cells of CA1 project to subiculum. signals then returned to EC
hypofrontality syndrome
state of decreased cerebral blood flow in the prefrontal cortex; symptomatic of schizophrenia, ADHD, bipolar disorder, and major depressive disorder
name the tiny projections which come off the top of the hair cells of the organ of corti
stereocilia
what medical therapies are likely to cause 2ndary hypertension
steroid therapy, combined oral contraceptive pill, monoamine ox-idase inhibitors.
what might you think about if a younger paitent had a central retinal vein occlusion?
sticky blood (thrombophilia screen, ask about contraceptive pill)
does glutamate inhibit or stimulate off-centre bipolar cells?
stimulate (hence they fire more in the dark)
does glutamate stimulate or inhibit retinal ganglion cells?
stimulate (hence they fire more in the light)
how does the periaqueductal grey create analgesia?
stimulation of PAG activates enkephalin-releasing neurons, which project to the raphe nuclei in brainstem. these release 5-HT down to the dorsal horn (laminae II) of spinal cord, signalling release of transmitters which bind μ-opioid receptors, inhibiting incoming nociceptive signals before they can be interpreted as 'pain'
what shape should a schild plot of a competitive antagonist be?
straight line with gradient of 1
describe the motor homunculus and somatosensory homunculus
stretching within the motor cortex and somatosensory cortex, they follow rouhgly the same pattern. 'leg' area is at the top near the midline, and the 'head' area is inferolateral
ocular dominance column
stripes of neurons in the visual cortex of certain mammals that respond preferentially to input from one eye or the other
what induces long term potentiation
strong tetanic activation of an afferent input sufficient to activate NMDA receptors (must overcomg the Mg2+ block). Ca2+ enters through NMDA, activates intracellular kinases, which increases postsynaptic AMPA receptors
good vision requires which 3 key things?
structurally healthy eye, proper focus of the eye, and intact neurological visual pathway
which part of the brain is responsible for learning and memory?
structures in the medial temporal lobes, part of the limbic system
what are the extrapyramidal pathways?
structures other than the corticospinal/bulbar tracts involved in motor control; the vestibulospinal, rubrospinal, tectospinal and reticulospinal tracts. (controlled by cerebellum, basal ganglia, vestibular nuclei, etc)
key differences between styes and chalazia
styes tend to be smaller/more painful, last for days rather than months,
which is arterial blood: extradural, subdural, subarachnoid haematoma
subarachnoid and extradural
blood in fluid collected from a lumbar puncture suggests what?
subarachnoid haemorrhage
what are the 3 meningeal 'compartments' outside of the brain
subarachnoid, subdural, epidural
how can you differentiate between subdural and epidural haematomas on CT scan
subdural are usually more longitudinally spread (less limited by vault bones), less dense, and make the sulci disappear
name 3 types of brain herniation
subfalcial, transtentorial, cerebellar tonsillar
in testing declarative memory, what is *free recall*?
subject asked to generate info from memory, eg participants are presented with a sequence of items, which they are subsequently required to recall in any order they wish
in testing declarative memory, what is *cued recall*?
subject is given a prompt/cue when asked to recall, eg participants given list of words, taken away, then 'Tell me all the words on the list that were animals'
instrumental learning
subjects learn that their responses have behaviourally significant outcomes: appropriate responses are *reinforced* by the behavioural outcomes
operant conditioning
subjects learn that their responses have behaviourally significant outcomes: appropriate responses are *reinforced* by the behavioural outcomes
classical conditioning
subjects learn the predictive value of a neutral event (ringing a bell) for another (food).
by which routes can glyceryl trinitrate be administed into the body
sublingually (tablet) or as a spray
substance P saporin technique to relieve pain
substance P saporin is a chemical mixture which can be administered to selectively destroy lamina I and II cells (part of spinothalamic tract). has little effect on acute pain but blocks chronic pain
which part of the basal ganglia is found outside the forebrain?
substania nigra; it is found in midbrain
SNpc stands for?
substantia nigra pars compacta
which brain structure releases the dopamine which acts on D1 and D2?
substantia nigra pars compacta
early symptoms of huntingtons
subtle problems with mood/cognition, followed by lack of coordination and unsteady gait
cataplexy
sudden and transient loss of muscle tone accompanied by full conscious awareness, often triggered by laughing, crying, terror, etc. affects roughly 70% of narcoleptics
what is orbital cellulitis? give some symptoms
sudden infection of the tissues around the eye (eyelids, eyebrow, and cheek). an *emergency! can spread to CNS*. painful, RAPD, reduced colour vision, proptosis. tender/warm erythematous skin associated with cold/fever + common in children
parieto-occipital sulcus
sulcus near the posterior end of each hemisphere that separates the parietal lobes and the occipital lobes. easily seen on medial hemisphere
flame shaped haemorrhages
superficial retinal haemorrhages which are flame shaped due to tracking of blood along horizontally arranged nerve fibres. occur in hypertension
which blood vessel can often squash the trigeminal nerve root? what does this cause?
superior cerebellar artery. causes trigeminal neuralgia.
which cranial fossa do the basal ganglia and thalamus lie in?
superior cranial fossa
where does info from both ears first come together to be processed
superior olivary nucleus
where is primary auditory cortex located?
superior temporal gyrus/lateral fissure
which 3 gyri lie anterior to the precentral sulcus?
superior, middle and inferior frontal gyri
topology
the way in which constituent parts are interrelated or arranged in space
maladaptive plasticity
theory behind phantom limb pain; in absence of a limb, other parts of the body take over that sensory area to 'fill the gap'
behaviourism
theory that all human/animal behavior can be explained in terms of conditioning, without appeal to thoughts or feelings, and that psychological disorders are best treated by altering behavior patterns/associative learning.
where is the interventricular foramen
there are 2 stretching upwards from the rostral end of third ventricle to the lateral ventricles
where are the nociceptors in the brain?
there are none (brain can't feel pain)
what is the basic mechanical model of pain?
there is a tissue injury, it hurts, and a defence response is sent to that area to help (much pain does not fit this model)
why do areas of ischemia appear bright on DWI
there is impeded water diffusion in extracellular space due to cytotoxic oedema. areas of restricted diffusion appear bright on DWI
why might parts of the brain appear paler in parkinsons disease?
there is loss of pigmented neurones (substantia nigra)
where is the second cranial ventricle?
there isn't one.
endogenous depression
there seems to be no reason/lifestyle change to cause the depression
are cell membrane chloride channels closed or open at resting potential?
theres a bit of flux, but mostly closed.
why is the cognitive effect of SSRIs seen within hours, but the mood response takes weeks?
theres an *idea* that SSRIs give you a positive bias in how you process the world - but this is just a framework; you need to go out in the world and experience things through this framework to change you enough to raise your mood
what is different about the afferents used in golgi tendon rather than muscle spindle?
they are Ib (not Ia) afferents. bit smaller and less sensitive.
what have amphetamines got to do with schizophrenia
they are associated with increased risk (probably to do with overloading dopamine release)
why are M1, M3 and M5 different from M2 and M4?
they are excitatory, and the even numbered ones inhibitory
what is the problem with CSF findings in MS?
they are nonspecific and can produce false positives/negatives
you cannot cause pschotic patients to take medication unless....?
they are sectioned
why are alpha 1 adrenoceptor blockers rarely used in hypertension?
they are too good - vasodilation is too strong and causes postural hypotension
why do muscarinic receptor antagonists increase heart rate?
they block the depressive input of the vagus nerve on the heart rate
why is it advantageous for most local anaesthetics to be weak bases?
they can exhibit ion trapping inside neurons (they work mainly on the inside of the cell membrane)
what is a key property of antihistamines which *cause sedation* vs those which don't?
they cross the BBB
why don't you give beta-blockers to type I diabetics
they dampen the adrenergic warning tremors/sense of foreboding induced by hypoglycemia, and also prevent adrenalin from stimulating the liver to make glucose, and therefore may make the hypoglycemia more severe
do pelvic splanchnic nerves join with spinal nerves?
they emerge with the spinal nerves from the ventral horn, but (unlike sypathetic fibres) they don't run in mixed bundles with spinal nerves - instead independent branches
give a situation where skeletal muscle blood vessels are innervated?
they never are
how would a tabetic gait affect a patients shoes?
they would be worn out uniformly across soles, because they are stomping down in a way that the entire flat foot strikes ground simultaneously, to give impact sensations
folia
thin leaflike folds in the cerebellar cortex
septum pellucidum
thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the corpus callosum down to the fornix
septum pallucidum
thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles. runs as a sheet from the corpus callosum down to the fornix
what are the classic symptoms caused by damage to middle cerebral artery
think FAST. loss of motor function in arm/face
is the cortical mantle thicker or thinner in shizophrenia
thinner
name 3 intravenous anaesthetics
thiopentone, propofol, etomidate
most autosomal dominant familial alzheimers (small propotion of all alzheimers) is linked to which genes?
those encoding amyloid precursor protein (APP) and presenilins 1 and 2
which sympathetic preganglionic neurons project well away from the spinal cord?
those going to the adrenal medulla (they are the exception)
which kind of neurons are located in the region between the dorsal and ventral spinal cord?
those involved in processes you don't really think about; central pattern generator, relay neurons, etc.
which light rays that enter the eye are not refracted?
those which enter the centre of the eye + pass straight to the retina
how do patients with bilateral amygdala lesions differ from those with bilateral hippocampal lesions in fear conditioning and declarative knowledge?
those with amygdala lesions do not acquire conditioned autonomic responses to vis/auditory stimuli, but do acquire declarative facts. hippocampal lesions, is the other way around. (those with lesions to both acquired neither conditioning nor facts)
after oligodendrocyte damage in MS, how are more oligodendrocytes made for remyelination?
thought to be from a stem cell or oligodendrocyte progenitor cell pool. perhaps when this pool runs out, this marks the end of remyelination
gabapentin mechanism
thought to increase GABA biosynthesis and bind to voltage gated calcium channels, to help epilepsy + neuropathic pain
which cells enable us to see colours?
three different types of cone cell, which respond roughly to light of short, medium, and long wavelengths
name the headache in a subarachnoid haemorrhage
thunderclap
define 'metabolic half life'
time taken for plasma concentration of a drug to decline to half its original level
define consolidation in terms of memory
time-dependent process by which a new trace is gradually woven into the fabric of memory and by which its components and their interconnections are cemented together
what points should you pick up in a hearing loss clinical history?
time/age of onset, conditions in which hearing loss is apparent, concurrent illness/trauma/symptoms, family history, german measles in mothers early pregnancy? drugs (antibiotics?), noise exposure (machinery/music?).
suprachiasmatic nucleus
tiny paired nucleus in hypothalamus (above optic chiasm) which controls circadian rhythm. receives direct input from retina (daylight)
function of ossicles
to amplify vibrations (about 22x) between the outer ear and inner ear - important because vibrations in the inner ear travel through fluid which is more dense than air
what is the purpose of the inverse myotatic reflex?
to protect muscles from harming themselves by stopping their contraction when tension is too high
why do Ia afferents project to the brain?
to tell primary somatosensory cortex whats going on in muscle spindles (which/how fast muscles are stretching)
where do the zonule fibres attach?
to the ciliary body and the lens capsule
is the cranial dura tightly adhered to the brain or the skull?
to the skull. (in some parts it even fuses with periosteum)
hyperprolactinaemia
too much prolactin in blood. can cause spontaneous flow of breast milk + disruptions in the menstrual period in women, and hypogonadism, infertility, breasts and erectile dysfunction in men
treatment for acute anterior uveitis
topical steroid eyedrops, cycloplegics (fixes pupil in dilation to prevent painful pupil contraction)
ATRX
transcriptional regulator protein, mutations of which can affect DNA methylation/have been linked to cancer
TIA
transient ischemic attack; brief episode of neurological dysfunction resulting from an interruption in the blood supply (stroke) that the body is able to break down/resolve
praxis
translating an idea into action
why can't you give dopamine as a chemical directly to a patient?
transmitters wouldn't cross the blood-brain barrier (must give L-DOPA instead)
crystalline lens
transparent elastic structure behind the iris by which light is focused onto the retina of the eye
the vertebral arteries travel in which foramina?
transverse foramina of C2-C6
give some causes of neuropathy
trauma, diabetes, Post herpetic neuralgias, HIV, Alcohol, Chronic pain after surgery, Cancer
give 3 key signs of parkinsons disease
tremor at rest, mask like face (poor emotional control of face), difficulty initiating movements/slow movements
amitriptyline
tricyclic antidepressant
where does the latent phase of herpes VZV live?
trigeminal and dorsal root ganglia
general sensory info is carried in which nerves from the head?
trigeminal nerve (general sensory includes touch, pressure, pain and temp - not the special senses)
which nuclei receive all somatosensory information in cranial nerves?
trigeminal sensory nuclei
what can cause parkinsons disease loss of neurones to suddenly increase?
triggers such as life events, head trauma, viruses, dodgy recreational drugs (MPTP)
meningioma
tumor, usually benign, arising from meningeal tissue of the brain/spinal cord. causes compression on brain from outside to in
methods of administration of local anaesthetics
surface anaesthesia (topical solutions/spray/lozenge/powder) nerve block (inject close to a nerve trunk), spinal anaesthesia (inject into subarachnoid space)
in which 3 medical fields are general anaesthetics used
surgery, dentistry, intensive care
prefrontal lobotomy
surgical interruption of nerve tracts to and from the frontal lobe of the brain; often results in marked cognitive and personality changes. used historically to 'treat' mental disorders
resection
surgical removal of part of an organ
which is more frequently interfered with by strokes, swallowing reflex or speech?
swallowing
do axons shrink or swell when damaged
swell
how is the organisation of the enteric nervous system different to the other autonomic systems?
symp + parasymp systems are two-neuron (pre- and post-ganglionic), whereas the enteric division is organised in plexuses within the gut and can function without input from the spinal cord
how does the length of the pre- and postganglionic axons differ between symp- and parasympathetic nervous systems?
symp has short preganglionics + long post, whereas parasymp has long preganglionics, synapsing in local ganglia into short postganglionics
how does the location of the postganglionic neurons in the periphery differ between symp- and parasympathetic nervous systems?
symp has thoraco-lumbar outflow (sympathetic trunk, abdomen) parasymp has cranio-sacral outflow (cranial nerves III, VII, IX, X + pelvic splanchnic nerves)
is the ANS sensory, motor or both?
symp- and parasymp divisions are *motor* systems. enteric division is *mixed*
describe how micturition requires both autonomic NS and somatic motor NS?
sympathetic activity is inhibited/parasympathetic increased to cause detrusor contraction + bladder neck relaxation. somatic activity to urethral sphincter is inhibited (relaxes it)
sacral splanchnic nerves
sympathetic efferent nerves which arise from the sympathetic trunk, supplying the aortic and superior&inferior hypogastric plexuses (much of the abdomen, pelvis and anal canal)
kernig's sign
symptom of meningitis; patient cant extend leg at the knee when the thigh is flexed because of stiffness in the hamstrings
fentayl
synthetic μ-opioid receptor agonist analgesic with a rapid onset and short duration of action. >50 times more potent than morphine + heroin
which protein is important in causing parkinsons?
synuclein (duplications/mutations in SNCA gene)
what is the most common form of neurosyphilis?
tabes dorsalis
3 examples of dorsal column syndromes
tabes dorsalis (common form of neurosyphilis), friedreich's ataxia (genetic degenerative disease of dorsal columns+spinocerebellar tracts), brown-sequard syndrome (spinal cord hemisection) *all deficits in touch/proprioception*
why might worn shoes (equally across the sole area) be a sign of neurosyphilis?
tabes dorsalis (form of neurosyphilis) blocks transmission of proprioception up spine; to compensate patients stomp feet when walking + use impact to guide movement...called a *tabetic gait*
what causes tabetic gait?
tabes dorsalis (form of neurosyphilis) blocks transmission of proprioception up the dorsal spine; means patients don't know where their feet are when they walk, so will stomp
what is the difference in the onset and offset time of methadone compared to heroin?
taken by mouth (slower onset) and has a slower offset than heroin
thought broadcasting
talking out loud/belief that your thoughts can be heard or read by everyone
which more accurately correlates with alzheimers severity, tangles or plaques?
tangles
organ of corti is sandwiched between which membranes?
tectorial membrane above and basilar membrane below
limbic lobe
term used to refer to area of medial temporal lobe containing cingulate gyrus along with corpus callosum, hippocampal formation, and amygdala (important group for behaviour/memory)
cisternography
test to view brain/diagnose CSF leakage. contrast injected into subarachnoid space (lumbar), then patient tilted with the head down and a CT scan is performed to see where the CSF and the contrast is leaking out
maddox rod
testing device used to measure strabismus by separating the images of each eye so that neural feedback is unable to align eyes; they drift to their resting positions
ames test
tests ability of a drug/its metabolites to induce mutations in bacteria - use mutant bacteria which can't synthesise histidine - see if the drug enables it to grow anyway
visual field test
tests for blind spots. usually, patient puts head into a machine. lights flash, patient must say if they can see lights or not. black areas on the results show blind spots
which part of spinal cord is tested in Rombergs test?
tests sense of proprioception, which requires healthy *dorsal columns*
which drugs are classic examples of damaging teeth/tooth development as side effect
tetracyclines (type of antibiotics)
what forms the lateral walls of the third ventricle?
thalamus + hypothalamus
the posterior limb of internal capsule is between which structures?
thalamus and putamen/globus pallidus
name some brain areas active in pain processing
thalamus, S1&S2, insula, anterior cingulate cortex, prefrontal cortex, amygdala, hippocampus, posterior parietal cortex, basal ganglia, brainstem
psychosis
losing touch with reaity; hallucinations + delusions. caused by schizophrenia, bipolar disorder, major depressive disorder
aphasia
loss of ability to understand or express speech, caused by brain damage to language area
describe a absence seizure
loss of awareness,maintained muscle tone, time + memory loss of seizure
describe a tonic-clonic seizure
loss of consciousness, muscles contract, no breathing (tonic phase ~ 1min). then rhythmic muscle jerking (clonic phase ~ 1min). time + memory loss of seizure
lesion of the trigeminothalamic tract leads to loss of which function in the face?
loss of temp and pain sensation
agraphia
loss of the ability to write or to express thoughts in writing because of a brain lesion in language area
apraxia
loss of the knowledge to perform learned/purposful movements, due to brain damage of premotor cortex
akinesia
loss or impairment of voluntary movement
do inner hair cells produce an AC response at high or low freqencies?
low
does a drug with a high MAC have a low or high potency?
low (higher the MAC, lower the potency)
ideally, should a general anaesthetic have a high or low blood solubility? why?
low (more rapid onset and offset)
ideally, should a general anaesthetic have a high or low MAC?
low MAC (high potency)
which 3 things lead to renin release (from the JGA)
low arterial BP (baroreceptors), low Na+ in glomerular filtrate, and high sympathetic drive (Beta-1 receptors)
difference between low and high intensity CBT
low involves a questionnaire worked through alone (eg 'beating the blues'). high is CBT with a person.
which is transmitted to brain more anterior in the primary auditory cortex, high pitch or low pitch sounds?
low pitch (from the apex of cochlea)
name the 3 types of auditory nerve fibres
low threshold fibres (most sensitive, with high spontaneous firing rate), intermediate threshold fibres, and high threshold fibres (only fire for louder sounds, but have the most dynamic range)
is cauda equina syndrome an upper or lower motor neuron lesion?
lower
does tabes dorsalis affect Upper or LMNs?
lower motor neurons
which cells clear necrotic brain tissue?
macrophages
which cells mediate the destruction of oligodendrocytes and myelin in MS
macrophages
which is more lateral and which medial of the optic disc and macula?
macula is lateral, optic disc medial
name the specialised regions within the succulae and utricles, containing hair cells which can sense tilt information/horizontal acceleration
maculae
somatosensory cortex
main sensory receptive area in brain for sense of touch. located in postcentral gyrus in parietal lobe. aka primary sensory cortex
mossy fibres (cerebellum)
major input to cerebellum, coming mainly from cerebral cortex (pontocerebellar pathway) as well as vestibular nerve, spinal cord, reticular formation. passes through middle + inferior cerebellar peduncles, where each axon branches to innervate granule cells in several cerebellar folia.
name the 3 ossicles in order
malleus, incus, stapes
how does damage to the prefrontal cortex affect patients?
marked personality and behaviour changes with loss of forethought, planning
parkinsons symptoms
masked/apathetic face, resting tremor, akinesia, waxy complexion,
contraindications of doing a lumbar puncture in suspected meningitis
may have septicemia (increased risk of bleeding), or high ICP (brains can come out)
how might prior antibiotics affect meningitis?
may mask severity of illness
how do you calculate KB
measure effect of increasing dose of agonist on a tissue, then repeat whole thing, each time in presence of more antagonist. plot dose-response curves from results. for a level of response, calculate the mean dose ratio between antagonist + control. use schild equation to plot a graph of log(DR-1) vs antagonist concentration - a *schild plot*. the x axis intercept = log(KB)
what is 'accomodative power' of eyes
measure of your ability to change the focal length of the lens. AP (in dioptres) = 1/near point - 1/far point (both in metres)
central sensitisation leads to which kind of hyperalgesia?
mechanical hyperalgesia
is the supplementary motor area lateral or medial?
medial
what are the main inputs to the VPL
medial lemniscus and neospinothalamic tract
fasciculus gracilis
medial pathway of dorsal column of spinal cord; carries tactile sensation + vibration + proprioception *from the lower limb* to the *gracile* nucleus in the medulla
patient HM had which brain structures removed? what effect did this have?
medial temporal lobe; most of hippocampus, rhinal cortex, amygdala. dense *retrograde and anterograde declarative* amnesia for life
is damage to cerebral cortex or thalamus more likely to produce coma?
thalamus. even small lesions can induce coma in thalamus, whereas large bilateral lesions usually needed in cortex.
neurotrophic hypothesis of depression
that depression is associated with reduced BDNF(Brain-derived neurotrophic factor) levels in hippocampus; and antidepressants act by raising BDNF
MSN
medium spiny neuron. special type of GABAergic inhibitory cell representing 95% of neurons within the striatum (structure in the basal ganglia). can either be D1-type MSNs of the "direct pathway" and D2-types of the "indirect pathway".
which is deeper in the skin, merkel's discs or meissners corpuslces? which of these is associated with *ridges* on the fingertip - and which with grooves?
meissners are deeper and on the ridges. merkel's found in the grooves
basilar membrane
membrane in the cochlea that bears the organ of Corti. separates scala media from scala tympani
declarative memory
memories for facts and events that can accessed for conscious recollection (e.g. my first bike was a present on my sixth birthday)
procedural memory
memories that do not require conscious recollection including habits (e.g. being able to ride a bike).
deficits in learning/memory/retrieval are known as what?
memory impairments
which vaccines are given standardly in the UK for meningitis
meningitis C, and as of 2015, meningitis B is also being given to babies
aseptic meningitis
meningitis with non-bacterial causes (could still be an infectious agent!)
Neisseria meningitidis is aka
meningococcus
name 2 superficial touch receptors
merkel's discs and meissners corpuscles
what are SA1 receptors?
merkel's discs: superficial touch receptors linked mechanically to surrounding keratinocytes. keratinocytes *slowly* activate afferent fibres via a *synapse*, detecting fine touch eg braille
which DA pathway is related to negative symptoms of shizophrenia
mesocortical
which DA pathway is related to positive symptoms of schizophrenia
mesolimbic pathway
which stays open for longer, ionotropic or metabotropic channels?
metabotropic
are opiod receptors metabotropic or ionotropic?
metabotropic (opiod molecules are too large for ionotropic)
which general anaesthetic is associated with causing renal failure
methoxyflurane
which pathway in the optic radiation enables you to see superior visual field?
meyers loop
what are the precursors of macrophages in the CNS
microglia
which cells act as the first and main form of active immune defence in CNS?
microglia
where is the dopamine system localised in the brain
midbrain (esp. substantia nigra) involving the striatum + frontal lobe
pretectal nuclei
midbrain structure composed of seven nuclei; comprises part of the subcortical visual system. important in visual reflexes (accommodation, pupillary)
mesencephalon
midbrain; develops from middle neural tube.forms the tectum and cerebral peduncle
a classic 'FAST' stroke involves which cerebral artery
middle
which artery runs along the lateral fissure?
middle cerebral
which artery supplies nearly all the lateral hemispheres of the brain
middle cerebral artery
which key vessel runs through the insular cortex?
middle cerebral artery
which artery is likely to cause a stroke which affects upper limbs only?
middle cerebral artery (affects superior lateral surface of brain)
from which cranial fossa do the entrances to the pterygopalatine fossa arise? what are they called?
middle cranial fossa. there are two: foramen rotundum and pterygoid canal
what travels through the foramen spinosum
middle meningeal artery
what happens when microglia are activated?
migrate to lesions, proliferate, morphological changes in surface proteins/cytokines etc
chlorpromazine
mild alpha 1 antagonist, mild antihistamine, mild antimuscarinic agent previously used as *low potency typical antipschotic*
MAC
minimum alveolar concentration - the alveolar conc (% by volume) of anaesthetic which, when equilibrium has been attained, give *safe level of anaesthesia/lack of response to pain* in 50% individuals. analogous to *EC50*
auditory threshold
minimum amount of loudness required to hear a frequency
is 5HT an excitatory or inhibitory neurotransmitter?
mixed
is ACh an excitatory or inhibitory neurotransmitter?
mixed
is dopamine an excitatory or inhibitory neurotransmitter?
mixed
Raphe nuclei
moderate-size cluster of nuclei found in the brain stem; main function is to release 5HT to the rest of the brain. can 'turn off' nociceptive activity
how does dopamine affect D2 neurons
modulator that decreases the firing rate upon receit of incoming synaptic activity into D2 neurons (hence inhibits the indirect pathway)
how does dopamine affect D1 neurons
modulator that increases the firing rate upon receit of incoming synaptic activity into D1 neurons (hence excites the direct pathway)
molecular memory consolidation
molecular process by which long term conductivity of synapses is affected
what is the most effective treatment for mania
mood stabilisers eg *lithium* - literally just lithium.
how are dendritic spines linked to memory?
more appear after learning experiences
why is voltage change slower in a membrane with many many ion channels open?
more channels open = lower resistance. V=IR, so lower resistance means lower voltage
more APs in retinal ganglion cells indicates what?
more light
is depression worse in morning or evening?
morning
what does hyperreflexia indicate?
most common cause is a spinal cord injury (UMN lesion), but coud be due to hyperthyroidism, drugs, electrolyte imbalance, serotonin syndrome, MS, Reye's syndrome, brain trauma.
medulloblastoma
most common type of pediatric malignant primary brain tumor. located in dorsal medulla/cerebellum. can be treated relatively effectively
subiculum
most inferior component of the hippocampal formation. lies between (and receives input from) the entorhinal cortex and CA1. is the main output from hippocampus
what are the molecular targets of general anaesthetics
most likely to act on transmembrane part of postsynaptic neuronal ion channels, eg enhancing *GABA A* and *glycine* receptor affinity, and increasing current through leak K+ channels causing hyperpolarisation
how does neuronal composition of brain change from birth through childhood?
most neurons die well before birth. usually neurons don't increase in number, but do increase connections + size + spines
are CTs used in neuro for acute or chronic conditions?
most of the time use an MRI scanner, but CT sometimes used for acute
what are angiomas
mostly benign tumors formed of a mass of blood or lymphatic vessels. can compress tissues/nerves / be a sign of liver cirrhosis
are cell membrane sodium channels open or closed at resting potential
mostly closed
do the basal ganglia have an ipsilateral or contralateral effect?
mostly contralateral
which frequencies does age related hearing loss most affect?
mostly high frequencies (above 1000 Hz)
what is the output from the striatum?
mostly medium spiny GABAnergic (inhibitory) projections to globus pallidus
function of dorsal rami
mostly motor and sensory supply to the skin + muscles of the back
is the basal plate predominantly sensory or motor
motor
vestibulospinal and reticulospinal tracts are important for which key function?
motor control of muscle tone and posture of body
what do the basal ganglia do?
motor control/inhibtion. indirectly affect lower motor neurons of the brainstem and spinal cord of *contralateral side*, including connections via thalamus to motor cortex, and projections to reticular formation
lower motor neurones
motor neurones with axons which terminate on an effector - bringing the impulses from upper motor neurones out to the muscles
three key things the basal ganglia control
movement, posture, muscle tone
how will a histological Substania Nigra pars compacta section from a parkinsons patient appear?
much emptier; death of dopaminergic neurons in this region
how many neurons are myelinated by a single oligodendrocyte?
multiple neurons - each neuron is wrapped around by many different oligodendrocytes
vecuronium
muscle relaxant in the category of non-depolarizing blocking agents. Vecuronium bromide is indicated as an adjunct to general anesthesia, to facilitate endotracheal intubation and to provide skeletal muscle relaxation
dorsal spinocerebellar tract originates from where
muscle spindles and golgi tendon organs in muscles of trunk/lower limb
proprioceptors
muscle spindles, golgi tendon organs + other joint mechanoreceptors which signify stretch, tension + joint angles. sense bodyily position/mediate reflexes
why must a memory system be capable of *encoding*
must be able to process information (stimuli) presented to form a representation, which can then be stored/retrieved.
how does huntingtons damage the brain?
mutatedly long huntingtin protein accumulates in the brain. it is toxic and damages striatum (caudate nucleus + putamen) in particular
what is function of a1 adrenoceptors in the eye?
mydriasis
name the 2 main plexuses of the enteric NS
myenteric + submucosal
name + describe 4 most common refractive disorders
myopia (nearsightedness): difficulty in seeing distant objects clearly; hyperopia (farsightedness): difficulty in seeing close objects clearly; astigmatism: distorted vision resulting from an irregularly curved cornea presbyopia: leads to difficulty in reading/seeing at arm's length, linked to ageing
name 3 common disorders of eye focus
myopia (short sight) hyperopia (long sight) and astigmatism (distorted vision due to cornea)
what are the scientific words for short sighted and long sighted
myopia and hyperopia respectively
what % of neurons in a sample are stained by the golgi stain
mysteriously only around 10%
what is the antidote for heroin overdose
naloxone
name an antagonist of the 3 main opiod receptors. what is its use?
naloxone. used to reverse opiods effects, eg in overdose/to make pills safer
give the 5 major categories of abused drugs with an example of each
narcotic analgesics (heroine), CNS depressants (barbiturates/solvents/benzodiazepines), CNS stimulants (cocaine, amphetamine), hallucinogens (LSD), NMDA receptor antags (ketamine)
Neuroleptic malignant syndrome
nasty lifethreatening side affect of neuroleptics (usually involves drug interaction). involves muscle rigidity, fever, autonomic instability, delerium
L-DOPA
natural chemical precursor involved in synthesis of DA, NA, and adrenaline. can be manufactured as drug and given to help parkinsons disease + dopamine-responsive dystonia
which requires greater refractive power to focus on, near or far objects?
near
what is the near point of your vision
nearest point at which you are able to bring an object into clear focus
which lense corrects myopia
nearsightedness can be corrected with concave lenses
in active areas of brain, is a negative or positive charge induced below the scalp?
negative
is Neisseria meningitidis gram + or -
negative
medial lemniscus
nerve fibre tract that carries sensory information from the gracile and cuneate nuclei in the brainstem to the thalamus. decussates on the way
optic radiation
nerve pathway which connects LGN to V1
difference between dorsal nerve root and dorsal ramus
nerve root emerges from dorsal grey matter and *merges with ventral nerve root* to form spinal nerve. dorsal ramus is a branch of this spinal nerve, containing *mixed fibres*
reticular formation
network of pathways in brainstem connecting the spinal cord, cerebrum, and cerebellum; gives rise to reticulospinal tracts, receives sensory info, forms reticular activation system/respiratory centres, mediates level of *consciousness/attention*
huntingtons disease
neurodegenerative genetic disorder that leads to mental decline + chorea
homunculus
neurological "map" of the anatomical divisions of the body: two types; sensory and motor
glasgow coma scale
neurological scale that aims to give a reliable, objective way of recording the conscious/unconscious state of a person. measures eye opening, verbal, and motor responses
mirror neurons
neuron that fires both when an animal acts and when the animal observes the same action performed by another
climbing fibre
neuronal projections from the inferior olivary nucleus in medulla to the cerebellum (deep cerebellar nuclei and purkinje cells)
upper motor neurones
neurones from the cerebral cortex or brainstem which connect to and control lower motor neurones (these are the neurones found in motor tracts etc)
two main types of cells in the CNS are?
neurons and glial cells
name some cells of the PNS
neurons fibroblasts to make collagen, glia - schwann cells
how do dorsal + ventral horn differ histologically?per
neurons in ventral horn are much larger than ventral horn (but little red dots of glial cell nuclei will be the same size)
what do SCN neurons do?
neurons of suprachiasmatic nucleus are inhibitory, and project to other hypothalamus + midbrain regions influencing sleep/waking
aminergic nuclei
neurons that use monoamines as a neurotransmitter
name some other substances in postganglionic autonomic nerves that can act as neurotransmitters (aside from ACh and NA)
neuropeptides eg vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY); small molecules such as 5HT, ATP and nitric oxide (NO).
tolman
neuroscientist who challenged skinner/behaviourism by showing that animals had a 'cognitive map' in their heads and without conditioning were more often able to choose correct path in direction of food
orexin
neurotransmitter made in lateral hypothalamus which regulates arousal, wakefulness, and appetite. lack of orexin can cause narcolepsy
which basal ganglia pathway degenerates in parkinsons
nigo-striatal pathway
which is a neurotransmitter; nitrous oxide or nitric oxide?
nitric oxide (NO)
does any autonomic nervous system activity involve consciousness?
no
is the amygdala part of the basal ganglia
no
does N2O enhance GABA A receptor function?
no (though many general anaesthetics do)
Do Gabapentin and pregabalin bind to GABA receptors?
no - although they are very similar to GABA, they act instead via calcium channels
can the visual system detect the absolute value of light intensity?
no - can only detect *difference* in light intensity
are benzodiazepines dangerous in overdose?
no - extremely safe. may relax muscle too much leading to airway block, but is difficult to die from them
does the enteric nervous system connect at all to the spinal cord?
no - is a separate entity.
is the rate of slow adapting receptors constant throughout the duration of the stimulus?
no - it is slightly higher at the start, but then constant
do anaesthetics produce distortions in the lipid bilayer?
no - it was thought to be the case but is proven wrong
what is characteristic of an *autonomic* NMJ?
no fixed synapse/motor end plate - neurotransmitters are released from varicosities along the length of the unmyelinated autonomic axon.
what is the clinical significance of the anterior limb of internal capsule?
no real clinical significance
can you view the brain with normal X rays?
no, because of the skull (and because its hard to differentiate between soft tissues with x-rays). CT x-rays are much better
do substantia nigra neurons directly stimulate movement?
no, but they play an indirect role by regulating the more direct role of the striatum
can pain be confirmed or denied by reference to tissue damage/pathophysiology?
no, must rely on the patient as the authentic reporter - pain can be experienced even without tissue damage
are there inhibitory synapses at NMJs?
no, only in CNS
does angiotensin work on adrenoceptors?
no, works on its own AT receptors
do foetal alcohol syndrome patients always have facial defects?
no. Facial defects are a good indicator of brain damage but are not always found in those affected
name 4 things which can increase pain experience
nocebo (this pill will make pain worse), inflammation, stress-induced hyperalgesia (eg going to dentist), and neuropathic pain
withdrawal reflex
nociceptive inputs in lower limb/foot activate fast A-delta pathway, leading to flexor contraction and extensor inactivation (withdraw your limb by lifting up leg). also activates opposite leg extensors to push other leg down for support
what forms the free nerve endings of primary afferent Aδ and C fibres?
nociceptors
stereocilia
non-motile apical modifications of the cell, longer than microvilli and more similar to the cell membrane proper. found in vas deferens, epididymis, and inner ear
what causes microglia cell activation
non-specific reaction to almost all injury of the brain: Inflamm-ation, tumour, hypoxia, trauma, neurodegeneration, demyelination etc.
which parts of the cerebellum operate at a conscious level?
none; it operates at an entirely unconscious level
gliosis
nonspecific reactive change of glial cells in response to CNS damage. usually involves proliferation/hypertrophy of several types of glial cells, mainly astrocytes
which is better at activating alpha receptors, adrenaline or noradrenaline?
noradrenaline
sleep and wakefulness are controlled by which diffuse modulatory systems of the brain?
noradrenaline, acetylcholine, 5-HT, and dopamine systems
emmetropia
normal refractive condition of the eye. it focuses parallel light rays on retina without need for accomodation
how far down spinal cord does tectospinal tract travel?
not much further than cervical region
can T cells pass through the BBB?
not often, except in cases such as MS, where they are encouraged to by integrins / a breakdown of the BBB
why would you give ropinirole (dopamine agonist) for restless legs?
not really known - it is a paradox.
why don't all anaesthetics go through stage 1 of anaesthesia?
not that many of them have analgesic properties
phrenology
now abandoned study of the shape of skull as indicative of the strengths of different aspects of your personality.
pontine nuclei
nucei in the ventral pons which receive info from ipsilateral motor cortex, and project it to the contralateral cerebellum
in which part of the striatum does cocaine raise dopamine levels?
nucleus accumbens
name the limbic region of the striate nucleus
nucleus acucmbens
which is higher in the medulla, nucleus gracilis or nucleus cuneatus? which is more medial
nucleus cuneatus is higher, gracilis is more medial
locus coeruleus
nucleus in the pons involved with physiological responses to stress and panic; the principle site of brain NA synthesis
locus ceruleus
nucleus in the pons involved with stress, arousal/attention, posture. principal site for brain synthesis of NA. can receive signals from periaqueductal grey to help decrease nociception
tuberomammillary nucleus
nucleus of histamine-releasing neurones within dorsal hypothalamus, involved in arousal, learning, memory, sleep
hypaesthesia
numbness; diminished capacity for physical sensation, especially of the skin
subjective VS objective tinnitis
objective is produced by a physical source within the body - doctor can here during examination - more treatable. subjective there is no physical generator (can only be heard by the patient)
associative visual agnosia is associated in lesions where in the brain?
occipital and temporal cortices. mainly bilateral lesions
what does the posterior cerebral artery supply?
occipital lobe
what kind of stroke causes tunnel vision and why?
occipital lobe has dual blood supply from middle and posterior cerebral arteries - if one is blocked, you have 'macular sparing'
difference between on and off bipolar cells
off cells have AMPA receptor - their action is increased by glutamate, so they fire more in the dark. on cells have mGluR6, which finds glutamate inhibitory, so they fire more in the light
promazine
old but still used antipsychotic of the phenothiazine class
aside from the brain and spinal cord, which other structures are part of the CNS?
olfactory nerves, optic nerves, and the retina
in the CNS, what makes myelin?
oligodendrocytes
which cells produce white matter myelin
oligodendrocytes
cingulate sulcus
on medial hemispheres, sulcus which separates frontal and parietal lobes from the cingulate gyrus
cisterna magna is located where
on the back of the medulaa, below cerebellum and abve foramen magnum
where in the brain are cerebral aneurysms usually found?
on the circle of willis
where are 90% of type 1 synapses found?
on the heads of dendritic spines of striatal MSN
describe the relationship between intracranial pressure and volume
once the patient reaches a high ICP, a small increase in volume will cause a much larger jump in ICP
where is the caudate nucleus?
one in lateral wall of each lateral ventricle
delta waves
one of the lowest frequency and highest amplitude brain waves. associated with infants/adults in deep (slow-wave) sleep
acute anterior uveitis
one of the most common presentations of uveitis; front portion of uvea is inflammed
mammilary body
one of two small round structures on the undersurface of the hypothalamus. form the terminals of the anterior arches of the fornix. important for recollective memory
which has a larger soma, a motoneuron with many terminations, or one with very few terminations?
one with many terminations (requires more soma for nutrition for its branches etc)
understanding speech in a loud restaurant requires high or low threshold fibres?
only high threshold fibres. they require a louder volume to fibre, but have a more dynamic range than low threshold fibres for distinguishing sounds
is it possible for the eye to make slow movements (as opposed to saccades?)
only if there is a moving object for your eyes to track
is the atrophy in upper or lower motor neuron lesions?
only lower atrophy = wasting (of muscles in this case)
are benzodiazepines water soluble?
only one type - Flunitrazepam
which of these are 'readily reversible': coma, general anaesthesia, sleep
only sleep
how do opoid receptors cause inhibition?
open K+ channels (except Kappa opoid receptor, which closes Ca2+ channels) hence stopping action potentials
difference between closed and open medulla
open medulla is higher up and has *no central canal*
neuropore
opening in the anterior (rostral) or posterior (caudal) end of the neural tube of the developing embryo. failure to close causes NTDs
who do you have to notify if you see a patient in hospital with meningitis
the 'proper officer' at local council or local health protection team (HPT). They will pass on to public health england
what is the 'ISO' of an audiogram?
the *International Organization for Standardization* threshold levels that audiometers are calibrated to. these levels are used as a 'normal' so that when intensity of 0dB is indicated, the average person will be at the threshold for hearing that frequency. a -ve point indicates better than average hearing
second order afferent neurons carrying proprioceptive info and discriminative touch form what?
the *dorsal columns*
area V1
the *primary* visual cortex; part of the visual cortex which receives sensory input from the thalamus
second order afferent neurones carrying touch/pressure, pain and temp form?
the *spinothalamic tract*
nucelus of solitary tract
the *taste* nucleus which also receives unconscious info from carotid body + sinus (general visceral afferent). important for autonomic control and parts of it form the dorsal inspiratory respiratory centre
kainate receptor
the 3rd main type of glutamate receptor (aside from AMPA and NMDA). they are ion channels of 4 subunits, permeable to Na+ and K+
in testing declarative memory, what is *recognition*?
the ability to correctly decide whether they have encountered a stimulus previously in a particular context; participants shown list of words, then presented with individual words: 'old or new word?'
what determines the shift of a dose response curve between two experiments, with and without a competitive antagonist?
the antagonist affinity for the response-inducing receptor, and the efficacy of the antagonist once bound.
telencephalon
the anterior of the two vesicles formed by specialization of the prosencephalon in embryonic development. Forms the cerebrum. Called also endbrain
panums zone of fusion
the area in and about the macula of retina in which stimulation of noncorresponding retinal points results in stereoscopic vision
centre-surround receptive field
the area within a ganglion cells receptive field is divided into centre (can contain either ON or OFF bipolar cells) and surround (will contain opposite type bipolar cells to centre). this functions to *emphasise edges/contrast in visual field*
blink artefacts in EEGs are caused by?
the blink musculature
drainage of aqueous humour from the eye is through where?
the canal of schlemm
which part of the lateral ventricles have a choroid plexus
the central part, and the superior part of the inferior horn (not anterior or posterior horn)
name the middle (vascular) layer of the eyeball
the choroid (forms ciliary body and iris anteriorly)
neuropil
the complex network of unmyelinated axons, dendrites, and glial branches that form the bulk of the CNS grey matter
blood:air partition coefficient
the conc of a substance in blood, relative to that in the air *at equilibrium*
pterygopalatine fossa
the deepest part of the pterygopalatine fissure (between sphenoid/maxilla/palatine bones)
where are the spines found on a medium spiny neuron?
the dendrites
metastasis
the development of secondary malignant growths at a distance from a primary site of cancer
tectum
the dorsal part of the mesencephalon, responsible for auditory and visual reflexes
how do middle ear bones amplify ( increase the pressure of) soundwaves?
the ear drum has 20x the surface area of the stapes, hence the stapes *concentrates* the pressure. this is added to by the lever action of ossicles and buckling of ear drum
the pineal gland is a component of which part of the diencephalon?
the epithalamus
superior colliculus is important for controlling movements of which organ?
the eyeballs
what happens if you stimulate the *frontal eye field*?
the eyes will look in the opposite direction to the side of the brain you stimulated
which parts of upper body do not have sensory input to the fasciculus cuneate? what structure carries corresponding info from these places?
the face and ear - info from here is carried by *principal sensory nucleus of trigeminal nerve*
which cranial nerves don't attach to the brainstem
the first two (olfactory and optic) which attach directly to the forebrain
soundwaves travel along which duct of the cochlea?
the floor of the scala media; the basilar membrane
what is ultrafiltrate?
the fluid present in the nephron; the glomerular filtrate
corpora quadrigemina
the four colliculi—two inferior, two superior—located on the tectum (the dorsal midbrain). they are reflex centres for vision + hearing
habitutation
the gradual waning of a response with repeated presentations of a stimulus (cancels out background information)
flexor reflex afferents
the group of nociceptive afferent neurones that transmit information via Aδ and C afferent fibers and produce the flexor withdrawal reflex
dominant hemisphere
the hemisphere which has the language areas in it (usually the left)
alexia
the inability to see words or to read, caused by damage to the language area of brain
which basal ganglia pathway involves external globus pallidus and subthalamic nucleus?
the indirect pathway
which two key arteries supply the brain?
the internal carotid arteries and internal carotid arteries
which pupillary light reflexes are affected in transtentorial herniation?
the ipsilateral oculomotor nerve is compressed, so ipsilateral pupil is areactive. contralateral consensual light reaction is preserved because optic nerve still intact
Pure tone audiometry
the key hearing test used to identify hearing threshold levels of an individual, enabling determination of the degree, type and configuration of a hearing loss
genu
the knee OR a part of certain structures resembling a knee (eg the bend in the internal capsule)
temporal horn of lateral ventricle
the largest, inferior horn of lateral ventricle, curving around the thalamus
cortical mantle
the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum.
which side of vision is usually neglected by hemispatial neglect? why?
the left side, because the lesions most often occur in the right parietal lobe
at which level do spinothalamic tract neurons cross the midline
the level at which the C&Aδfibres enter the spinal cord + synapse with 2nd order neuron
which part of the homunculus is supplied by the anterior cerebral arteries
the lower limb (medial part)
where do most corticospinal axons cross the midline (decussation of the pyramids)?
the lowest part of the medulla
the two sides of the diencephalon are separated by what?
the lumen of the third ventricle
bupivacaine
the most commonly used local anaethetic in epidurals
pethidine
the most widely used opioid analgesic in labour and delivery
which brain area seems to be most involved in memory priming
the neocortex
why was it comparitively easy to see which neurons are being lost in parkinsons disease?
the neurons are part of the substantia nigra; contain black pigment (much more noticable than just a random bit of grey matter)
which part of the ear contains inner hair cells and outer hair cells?
the organ of corti (in the scala media)
what does the amplitude of a sound wave correlate to?
the perceived loudness
in vision, what is the receptive field
the photoreceptors/part of the retina which connects to a ganglion cell is the *receptive field* of that ganglion cell
uvea
the pigmented layer of the eye, lying beneath the sclera and cornea, and comprising the iris, choroid, and ciliary body
what does the frequency of a sound wave correlate to?
the pitch
fulcrum
the pivot about which a lever turns
what is the neuranatomical region of M1? include its brodmann area
the primary motor cortex (M1) is found in the precentral gyrus in the frontal lobe. brodmann area 4
descending corticospinal fibres form a prominant ridge on the ventral medulla called?
the pyramids
coronary angiography
the radiographic visualization of the coronary vessels after injection of radiopaque contrast media
the rods/cones connected to a bipolar cell form what?
the receptive field centre (if directly connected) or the receptive field surround (if indirectly connected via horizontal cell)
where to the rubrospinal tract fibres originate?
the red nucleus (in rostral midbrain)
why mustn't you forcefully rupture a stye
the staphylococcus aureus with spread
what is the only monosynaptic reflex in the body?
the stretch reflex, initiated when a muscle is stretched (generated in muscle spindles)
the spinal cord is shorter than vertebral column, so to emerge from their correct *intervertebral foramen*, lower spinal nerve roots descend to it *in which meningeal layer?*
the subarachnoid space
sensitization
the sudden enhancement of responses to a stimulus after exposure to a highly arousing event
how is the cerebellum attched to the brainstem?
the superior, middle and inferior peduncles (masses of nerve fibres either side of the 4th ventricle)
all pathways carrying specific info to the cerebral cortex synapse where?
the thalamus
where do primary afferents entering the brainstem via the trigeminal nerve terminate?
the trigeminal sensory nucleus, one of the cranial nerve nuclei in the pons
optic nerves pass through the optic chiam to become what?
the two optic tracts (L + R)
what proportion of the vertebral column is occupied by the spinal cord?
the upper 2/3rds. (it terminates at L1)
which reflexes are eye movements to *track a moving subject*
opto-kinetic reflexes
what does OPV stand for?
oral polio virus
which characteristic facial expressions do mice show in response to pain which humans also show
orbital tightening, nose bulge, cheek bulge
tonotopic map
orderly projection of inputs originating from the cochlea to sensory areas in the brain, such that neighboring neurons in the target regions respond to progressively higher frequencies
hypocretin is AKA
orexin
name the neurons in the lateral hypothalamus which activate the ascending arousal system
orexin neurons
organ of corti
organ lying against the basilar membrane in the cochlear duct, containing neuroepithelial hair cells/several types supporting cells. converts sound virbrations into cochlear nerve signals
is CTZ inside or outside the bloodbrain barrier?
outside
hyperacusis
oversensitive hearing due to increased irritability of the sensory neural mechanism; intolerance to ordinary sound levels. exacerbated post-earplugs
what are RA2 receptors?
pacinian corpuscles: fluid-filled-capsulated ending of a sensory nerve, found deep in dermis. acts as a rapidly adapting receptor for pressure and vibration
scoville and milner
pair who studied HM and first wrote a famous paper (based on him) which outlined the hippocampus as being needed for transforming short term memories into long term memories
what are the two major neuronal inputs to purkinje cells of cerebellum? are they excitatory or inhibitory?
parallel fibres and climbing fibres (both glutaminergic excitatory)
when baroceptor firing increases, how is parasympathetic and sympathetic activity changed?
parasymp becomes more active and symp becomes less active (to lower BP)
sympathetic + parasympathetic systems: which is more 'direct' and which is more 'divergent'?
parasymp outflow = more direct (local ganglia). symp outflow = more divergent eg each preganglionic neuron can produce responses coordinating between different internal organs/targets
is micturation sympathetic or parasympathetic
parasympathetic
is pupil constriction symp- or parasympathetic?
parasympathetic
hemispatial neglect
parietal cortex lesion means attention/awareness of one half of space is compromised. when asked to copy pictures, though patient can see the whole image, they only draw one half, ignoring the other.
what is the major cause of hemispatial neglect?
parietal cortex lesions (usually right parietal)
stimulation of the subthalamic nucleus helps treat which disease? why?
parkinsons (they carry a portable electric stimulator).
tremor at rest, slow movements, rigidity, postural instability. classic symptoms of what?
parkinsons disease
what are the two primary output nuclei of the basal ganglia system to the motor thalamus?
pars reticulata and globus pallidus internal segment
helicotrema
part of cochlear apex where the scala tympani and the scala vestibuli meet; hair cells near here detect low frequency sounds
brodmann area 7
part of superior parietal lobe (posterior to primary somatosensory cortex). uses visual and proprioceptive info to located *where* objects are in space
where is the fusiform gyrus
part of temporal lobe between the inferior temporal gyrus and the parahippocampal gyrus
striate cortex
part of the occipital cortex that receives the fibers of the optic radiation from the lateral geniculate body and is the primary receptive area for vision. includes V1
posterior spinocerebellar tract
part of the somatosensory system ; runs parallel to anterior spinocerebellar tract, up the latero-dorsal outer edge of spinal cord. conveys unconscious proprioceptive info from the body to the cerebellum
tinnitus
pathologically generated sounds; ringing/hissing/roaring or buzzing in the ears or head
dissociative anaesthetic
patient is aware of surroundings, but is detatched from them, eg ketamine
if you electrically stimulate the somatosensory cortex what happens?
patients feel a tingling sensation on the contralateral side of the body
pain wind up
perceived increase in pain intensitywhen a given stimulus is delivered repeatedly above a critical rate. caused by repeated stimulation of C fibers, leading to progressively increasing electrical response in dorsal horn neurons
schultz
performed experiments on dopamine neurons in striatum, finding that this area seems to be most involved/changed in operant conditioning
which brain structure, seen in a midbrain cross section, has descending control over pain?
periaquaductal grey
describe plasticity in pain system at a peripheral level
peripheral sensitization, denervation, ectopic activity (random pain)
how do you describe the meningitis rash?
petechial/purpuric non-blanching rash or signs of meningitis
how are mirror boxes used to treat pain?
phantom limb pain patients can feel like their fist is clenched/nails digging in. mirror box used to make it seem like patient is looking at their fist and unclenching it - alleviates pain in short term
aside from alzheimers, name some other tauopathies
pick's disease, corticobasal degeneration, progressive supranuclear palsy, frontotemporal dementia with parkinsonism
which do people remember better, pictures or words?
pictures
which small structure behind the third ventricle can calcify (without causing problems) from an early age?
pineal gland
this scan shows calcification in which 3 key areas?
pineal gland, and both choroid plexuses
vasogenic brain oedema
plasma-filtrate (incl. proteins) oedema in the interstitium of the brain caused by breakdown of the tight endothelial junctions that make up the blood-brain barrier
peripheral sensitisation to pain
plastic changes in C fibre axon terminals lead to amplified pain post injury (particularly more sensitive to thermal stimulation - think sunburn)
central sensitisation to pain
plastic changes in dorsal horn neurons (involving microglia) amplify incoming pain sensory info *from A and C fibres* - this is troublesome in pain relief
basilar artery runs up the front of which part of brainstem
pons
3 structures of the hindbrain
pons, medulla, cerebellum
optic ataxia
poor hand/eye coordination - inability to benefit from visual guidance in reaching for an object.
tuberoinfundibular system
population of dopamine neurons in the arcuate nucleus of hypothalamus. project to pituitary median eminence to prevent prolactin secretion
pars compacta
portion of the substantia nigra containing dopaminergic neurones (they die in parkinsons)
is streptococcus penumoniae gram + or -
positive
what kind of symptoms are relieved by 'typical' antipsychotics
positive symptoms eg hallucinations/delusions
what are the two overarching reasons that drugs induce dependence
positively reinforcing (drug is rewarding/pleasurable) and negatively reinforcing (drugs taken to avoid withdrawal syndrome)
what is the neuranatomical region of primary somatosensory cortex? include its brodmann area
post central gyrus, parietal lobe. brodmann area 3, 1 and 2 (from ant to posterior)
name 4 gyri of parietal lobe
postcentral, supramarginal, angular, intraparietal
are the inferior cerebellar peduncles on the anterior or posterior surface of the medulla?
posterior
which cerebral artery supplies the thalamus
posterior
which is more problematic; lesions in the anterior or posterior limb of the internal capsule?
posterior
after transtentorial herniation, infarctions occur in the terriftory of which artery?
posterior cerebral artery
which artery supplies most of the visual areas of the brain?
posterior cerebral artery
which artery supplies the dorsolateral medulla
posterior inferior cerebellar artery (PICA)
PICA
posterior inferior cerebellar artery, largest branch of the vertebral artery, and one of the three main arterial blood supplies for the cerebellum
rachischisis
posterior neuropore of the neural tube fails to close in development; vertebrae overlying do not fully form + remain unfused and open, leaving the spinal cord exposed
which kind of synechiae are associated with AAU
posterior synechiae
what is NMDAR
postsynaptic ligand-gated ion channel which transports cations (Na+/Ca2+) into dendrite. opens only when glutamate and glycine (the ligands) are bound to the receptor, and the postsynaptic cell is depolarized (which de-attracts the Mg2+ blocking the channel)
what is AMPAR?
postsynaptic ligand-gated ion channel. when glutamate (the ligand) binds, it transports cations into dendrite
what is inversly proportional to Minimum Alveolar Concentration?
potency
tetrodotoxin
powerful neurotoxin found in some sea creatures. highly selective voltage gated Na+ channel antagonist - prevents action potentials, causing paralysis whilst conscious
what are the vascular causes of 2ndary hypertension?
preeclampsia, coarction of aorta, renal artery stenosis
laser peripheral iridotomy
preferred procedure for treating angle-closure glaucoma caused by pupillary block. laser beam creates small hole allowing the aqueous humour to pass directly from the posterior chamber into the anterior chamber, bypassing the pupil and equalising pressure
problem solving and goal-directed behaviour is dealt with in which part of brain?
prefrontal areas of frontal lobes (executive function)
name the cortex rostral to the motor areas of the brain
prefrontal cortex
which region of the brain expierences particular cell death in chronic pain patients
prefrontal cortex
are autonomic neurons myelinated?
preganglionic axons are lighty myelinated, and postganglionics are unmyelinated
which neurons of the ANS are located in the central nervous system?
preganglionic neurons
which neurons are found in the lateral horn of the spinal cord?
preganglionic sympathetic neurons
SMA and PM are both included in which region of the brain?
premotor cortex
which has higher level coding in, M1 or Premotor cortex?
premotor cortex. (premotor area has activity when you are just thinking about a movement, supple
name the condition whereby elasticity of the lens decreases so lens fails to change to globular shape during accomodation?
presbyopia
how do OHCs perform *electric-mechanical transduction*?
prestin they contain causes them to contract when stimulated, feeding energy back into the basilar membrane + boosting vibrations of sound. creates *cochlear amplification*. without OHCs, our hearing *sensitivity* decreases greatly
when do huntingtons patients stop making chorea movements?
pretty much never except during deep sleep
where do the basal ganglia outputs project to?
primarily the thalamus (only those parts connected with frontal cortical regions, and those regions important in motor control - VA, VL, DM). also superior colliculus (eye mvments), reticular formation, pedunculopontine nucleus, habenula
which is more sensitive to produce movement due to electrical stimulation; primary or premotor cortex?
primary (premotor will still produce movement, but requires higher stimulation)
what is brodman area 4?
primary motor cortex
what is the function of brodmann areas 17
primary visual cortex - the simplest, earliest cortical visual area, interpreting 'edge detection' information from the LGN of thalamus and sending it on to V2
what is the neuranatomical region of V1? include its brodmann area
primary visual cortex is located at the calcarine sulcus. brodmann area 17
snellen chart
printed card with letters in lines of decreasing size; used to test visual acuity.
which neurodegenerative diseases are human-human transmissable
prion protein diseases (Creutzfeldt-Jakob-Disease, Gerstmann-Sträussler-Scheink er-syndrome, etc). amyloid beta can also be transmitted (linked to alzheimers)
why do amnesia patients lose their more recent memories and retain older ones?
probably because most amnesia patients have damage to the hippocampus, and the older memories have, over time, become more located/connected to the *cortex* than the hippocampus(+ associated structures): called *consolidation*
describe axon guidance
process by which neurons send out axons to reach the correct targets. at the tip of growing axons is a motile *growth cone* which contains receptors for attractive/repellant 'guidance cues' in the environment. these attractive molecules are turned off upon reaching target
tectospinal tract function
produces reflex (involving superior calliculus) in which head turns to face an auditory/visual stimulus
symptoms of MND initially present as?
progressive weakness, muscle wasting, muscle fasciculations, spasticity/stiffness in arms + legs, struggle swallowing/breathing, hyperreflexia
ascending arousal system
projections from the brainstem/posterior hypothalamus throughout the forebrain,
in which cerebral lobes is visuospatial function organised?
projections to parietal lobes
in which cerebral lobes are faces and objects recognised?
projections to temporal lobes (memory)
general seizures
prolonged synchronous discharge of many neurons involving whole brain - fast onset.
which betablocker is commonly used in thyroid storm and why?
propanolol. beta blockers reduce the effect of circulating thyroid hormone on end organs. propanolol blocks both B1 and B2 receptors especially well
which is least selective for B2 adrenoceptors, propranolol, atenolol or metoprolol?
propranolol
put these in order from fastest to slowest: thermoreceptors, proprioceptors, nocicptors, cutaneous mechanoreceptors
proprioceptors, cutaneous mechanoreceptors, thermoreceptors, nociceptors
what is the function of hyperalgesia after injury
protect the injury to allow recovery and repair
functions of the outer ear
protection, amplification, localisation (where has the sound come from in vertical/horizontal planes)
what is the main function of pain
protective - it prevents damage from occuring.
α-Synuclein
protein abundant in neural tissue, which when mutated, aggregates to form insoluble fibrils known as Lewy bodies
postsynaptic density
protein dense specialization attached to the postsynaptic membrane - concentrates neurotransmitter receptors etc to align with *active zone* on presynaptic neurone
PKC is short for?
protein kinase C
presenilin
protein sub-component of gamma secretase that is responsible for the cutting of Amyloid precursor protein. mutations in presenilin gene hence cause early onset familial Alzheimer's Disease
ephrin
proteins which act on the ephrin receptor. repellent on axon growth cones so responsible for segmental pattern of spinal nerves
name 2 types of hypertension aside from systemic
pulmonary + portal hypertension
in which cells in the body does phosphorlyation of AMPA receptors *decrease* AMPA receptor expression?
purkinje cells in cerebellum. (all other cells, it would *increase*)
how does pushing in the oval window (by the stapes) affect the round window?
pushes round window out into middle ear cavity (fluid in the inner ear is not compressed)
two ways of treating cerebral berry aneurisms
put clips around their necks or 'fill them up'/interventional radiology
where are the pyramids and olives found on the medulla?
pyramids are lateral to the ventral midline fissure, and olives are lateral to the pyramids
how is *quality* of a sensory stimuli encoded in the nervous system?
quality of a stimulus (is it pressure, heat, etc) is encoded by the identity of the afferent fibre its stimulates, i.e. the receptor type + its location in body
which are more addictive, drugs which are eliminated quickly, or slowly?
quickly, since slow clearance of a drug diminishes severity of acute withdrawal. (but longer lasting drugs can increase addiction by increasing duration of action on target proteins)
side effects of TCAs
quite sedative, a1 adrenoceptor antagonists (lower BP), muscarinic receptor antagonists
once they start asymmetric divisions to develop neurons, what are neuroepithelial stem cells renamed?
radial glial cells
myelography
radiographic examination of spine. contrast medium injected into spine to detect pathology of the spinal cord, including the location of a spinal cord injury, cysts, and tumors
deprenyl side effects
raises BP and is metabolised into *metamphetamine* (crystal meth.... a neurotoxic substance)
nystagmus
rapid involuntary rhythmic movement of eyeball. may be horizontal, vertical, rotatory, mixed
guillain-barre syndrome
rare polyneuropathy. fast onset muscle weakness as a result of autoimmune attack on the myelin of *peripheral nerves*. (this immune dysfunction may be triggered by an infection)
tyosine hydroxylase function
rate-limiting enzyme of catecholamine biosynthesis; converts tyrosine to L-DOPA
omni-directional
receiving signals from or transmitting in all directions (eg our sense of hearing)
which type of past memories are affected first in alzheimers and why?
recent *episodic* memories (due to hippocampus being first affected)
mesencephalic
relating to the midbrain (mesencephalon)
dystonia
relatively fixed abnormal postures in face/neck/trunk/limbs. a result of basal ganglia disorder
are the neural signals in the ON- and OFF-centre retinal ganglion cells separate or merged?
remain segregated in the retina and the LGN, then merge completely in the complex cells in primary visual cortex (V1)
what are the adverse sympathetic affects of adrenaline?
remember 'CATTRAP' : cold sweat, anxiety, tremor, tachycardia, reduced capillary refill, arrythmia, pallor
how do you treat cataracts?
remove clouded lens and put in a plastic one
why might you perfrom a ventrolateral chordotomy? how effective is this?
removes the part of the spinal cord where the spinothalamic tract is located - removes pain for *several segments below the cut* - though due to spinal plasticity this will return after a few weeks
what are the renal causes of secondary hypertension?
renovascular disease, glomerulonephritis, chronic pyelonephritis
long term potentiation
repeated presynaptic stimulation of a nerve that results in the long-lasting increased strength of a synapse. necessary for learning and memory formation ('if you use it, it gets stronger')
why was clozapine drug withdrawn as unsafe?
reports of agranulocytosis leading to death in some clozapine-treated patients (though it is now reinstated, provided sufficient blood monitoring)
impedance
resistance to flow/movement. eg 'how much does the material *impede* movement'
function of alpha retinal neurons
respond rapidly to movement in peripheral field (larger neurons)
function of beta retinal neurons
respond to fine detail in vision (smaller neurons)
is there a resting or intention tremor in parkinsons disease?
resting
chorea
restless, rapid, involuntary, dancelike movements (often resembles fragments of purposeful movements) seen in huntingtons disease
which is more important for consciousness, reticular formation or cerebral cortex?
reticular formation (even a small lesion in it can produce coma, unlike the cortex)
the axons of which cells weave together to create the optic nerve?
retinal ganglion cells
what kind of memory loss is seen in alzheimers
retrograde memory impairment (recent memory goes first, then loss extends back into the past as disease progresses)
moclobemide is a 'RIMA.' what does this mean?
reversible inhibitor of monoamine-oxidase-A
which pigment gives the retina its purple/red colour?
rhodopsin
which sinister (if clever) application does Flunitrazepam have
rhohipnol - date rape drug - used because it is powerful hypnotic + water soluble, but metabolised in such a way as not detectable the next day
optokinetic reflex
rhythmic nystagmus movements involving the visual system and its neural pathways. eg when looking out of train window, eyes follow a moving object with until it moves out of the field of vision, at which point eyes moves back to the position it was in when it first saw the object
gyri
ridge/elevation between two sulci on the cerebral surface in the brain
which amygdala is most involved in fear/negative processing
right amygdala
zonule fibres
ring of fibrous strands connecting the ciliary body with the crystalline lens of the eye. collectively known as suspensory ligament of eye
ciliary muscle
ring of smooth muscle in eyes middle layer which controls *accomodation* and *aqueous humour flow*.
vestibulo-ocular reflex
rotation of head in one direction eg to the right, activates vestibular apparatus and medial/lateral rectus muscles to move eyes to rotate in opposite direction (the left). maintains a fixed gaze on an object even when head moves
which is bigger, pterygoid canal or foramen rotundum
rotundum
which spinal pathway comes from the red nucleus and intermingles with the descending corticospinal tract?
rubrospinal tract
myelomeningocele
sac containing part of the spinal cord +meninges protrude through a gap in the vertebral column
most common type of cerebral aneurysm
saccular aneurysms; aka berry aneuryms (appear as round outpouchings)
name the leaping type of propagation down a myelinated axon
saltatory conduction
which cells surround dorsal root ganglia?
satellite glial cells
give 2 structural features which decrease potency of anaesthetics
saturation and hydrophilic groups (eg -OH, -NH2)
cochlear duct aka?
scala media
3 layers of the cochlea are?
scala tympani, scala media, scala vestibuli
drugs which block NMDAR (eg ketamine) have side effects indistinguishable from which psychotic disease?
schizophrenia
what are type II sensory fibres?
secondary afferent neurons which provide position sense of a still muscle, fire when muscle is static
netrins
secreted molecules that can act to attract or repel growth cones of new axons by binding to their receptors
lashley
sedated animals and knife-cut specific areas of their brain to see how they changed - tried + failed to find the engram . concluded memory is distributed
where are the red nuclei found in a midbrain cross section?
see pic
selegiline
selective irreversible MAO-B inhibitor - blocks break down of dopamine, NA, Ad, 5HT in the brain. used in early-stage parkinsons (not depression). has cardiac side effects
rolipram
selective phosphodiesterase-4 inhibitor (procognitive effects), once used to treat depression but now in research/development
SSRI stands for
selective serotonin reuptake inhibitor
what kind of memory is this: 'the capital city of france is paris'
semantic (factual) memory
interoception
sensitivity to stimuli originating inside of the body
is the alar plate predominantly sensory or motor?
sensory
acoustic neuroma
tumour which grows on the 8th nerve (affects hearing early on) and will soon impinge on the facial nerve too; illustrates the importance to the close relationship of the VIIth and VIIIth nerves
what might compress cranial nerves emerging from the brainstem?
tumours or aneurysms
weber's test
tuning fork is rung held to the top of head. distinguishes unilateral conductive hearing loss (tone heard in affected ear) from unilateral sensorineural hearing loss (heard in non-affected ear)
how might acute infarction change the appearance of neurons
turns the area pale
describe the retinal blood supply
two circulations both supplied by ophthalmic artery; uveal circulation (outer + middle layers of retina) and retinal circ (inner layer, travels with optic nerve as central retinal artery)
grid cell
type of neuron which interacts with hippocampal place cells to help keep track of spatial location even in absence of visual/auditory/tactile cues.
MR perfusion imaging
type of perfusion scanning using MRI and contrast. can show areas most perfused --> indicates those most active.
tyramine reaction
tyramine is normally broken down by MAO before it gets into blood, but if on non-selective MAO-inhibitors, it can enter blood, damaging VMAT 2 so monoamine storage vesicles release their cargo into cytoplasm and - pushes transporters to transport monoamines the 'reverse' way - into synapse. causes hypertensive crisis
where is aqueous humour produced? is this sympathetic or parasympathetically controlled?
ultrafiltration in the ciliary body. symp (B1 and B2 adrenoceptors).
in pavlovs experiment, what was the conditioned/unconditioned stimulus and response?
unconditioned stimulus: giving food. unconditioned response: salivating conditioned stimulus: ring bell conditioned response: salivate due to bell
bipolar vs unipolar depression
unipolar (major depression) affects 1/5th population, usually onset 25yrs. bipolar depression (depression + mania) affects <1% population, usually onset 30yrs old
how do unipolar, bipolar, and non-depressed people differ in their reaction times to happy/sad words?
unipolar are quicker at sad words, bipolar quicker at happy words, control subjects were equal at both.
what is the gender ratio of the effects of depression?
unipolar is 2:1 females:males, and bipolar is equally common in both genders
what are the causes of schizophrenia?
unknown - has many associated genes, could be viral, must be involved in adolescent development
what is sleep for?
unknown - likely to be restorative. adjusts muscle tension/brain metabolism/body temp. sleep deprivation leads to serious cognitive + physiological disturbances
what is pain
unpleasant emotional and sensory experience associated with actual or potential tissue damage, or described in terms of such damage
does the corticospinal tract contain lower or upper motor neurones?
upper
is babiski sign present in upper or lower motoneuron lesions?
upper
how are tendon reflexes affected in upper and lower motoneuron lesions
upper lesions = hyperreflexia, lower lesions = hyporeflexia/areflexia
how is muscle tone affected in upper + lower motor neuron lesions
upper lesions there is a spastic (spasming) tone, lower lesions there is a flaccid tone
scala vestibuli
upper perilymph-filled bony cavity inside the cochlea. conducts sound vibrations to scala media. extends from the vestibule of the ear to the helicotrema where it joins scala tympani
How do GPs diagnose depression?
use a *patient health questionnaire* for major depression, but for bipolar depression you use *mania symptoms* (abnormally high mood etc)
analgaesic
used for relief from pain
lancaster-regan chart
used to detect astigmatism of lens.
function of premotor cortex
uses spatial and sensory cues to execute movement and planning *visually guided voluntary movements*. also projects to spinal cord - possibly involved in behaviour
optogenetics
using genetic mechanisms to modify the CNS so that neurons can be activated by light
describe clinical patterns of MS over time
usually first shows between 20-40, then relapsing then remitting whilst progressing, with complete or incomplete remission.
how do calcifications appear in the brain?
usually located in the basal ganglia, glands, vessels/plexuses eg choroid plexus
name 5 main causes of painful visual loss
uveitis, acute angle closure glaucoma, keratitis, optic neuritis
diazepam is aka
valium
what creates eye colour?
variable amounts of eumelanin (brown/black melanins - more in brown eyes) and pheomelanin (red/yellow melanins - more in blue/green eyes) produced by melanocytes
choroid plexus
vascular CSF-producing structure, like a cauliflower perfused with blood, present in all brain ventricles -seen here superiorly within the 3rd ventricle
which causes more immediate motor loss, a tumour or a vascular occlusion
vascular occlusion
is the 'what' visual stream ventral or dorsal?
ventral - projects to temporal lobe
which 3 regions of the thalamus do the basal ganglia output to?
ventral anterior (VA), ventral laterall (VL) nuclei
which part of thalamus supplies PM and SMA?
ventral anterior nucleus
which part of thalamus is major input to primary motor cortex (M1)
ventral lateral nucleus
where do pelvic splanchnic nerves arise?
ventral rami of sacral spinal nerves S2, S3, S4
name the two pathways which each V1 transmits information to
ventral stream (or 'What' pathway) and dorsal stream ('Where' pathway)
what is the A10 nucleus?
ventral tegmental nucleus
how does hydrocephalus appear on a brain scan
ventricles are blown up, and CSF leaks into surrounding brain
which part of the hypothalamus contains sleep-promoting neurons?
ventrolateral preoptic nucleus
activity in which brain region induces sleep?
ventrolateral preoptic nucleus (sends suppressive projections to ascending arousal system)
aside from vertebrae, what else protects the spinal cord?
vertebral ligaments, meninges, fat, and cushioning fluid (CSF)
what travels through the C7 transverse foramen
vertebral vein and sympathetic nerves (vertebral artery goes *around* the foramen, not through)
subtarsal foreign body may present itself how in the eye?
vertical scratches around cornea which will show (with flourisine) as 'scribbles' on the eye surface from opening /closing eyelids
microscopic MRI
very high resolution MRI imaging (down to nanometer scale, in some cases comparable with histopathology)
post rotational nystagmus
vestibular nystagmus; occurs when the body is rotated and then the rotation stopped, due to *adaptation* of vestibulo-ocular reflex. If, while sitting in swivel chair, body is spun to the right, the nystagmus during rotation has its slow component to the left (eye tracking left, then jumping). When rotation stops, the slow component is to the right (feels like spinning the other way)
which reflex stabilises eye position in space during movements?
vestibulo-ocular reflex
which reflexes act to stabilise an image when there are head movements?
vestibulo-ocular reflexes
how do vestibulospinal reflexes differ from cervicospinal refelexes?
vestibulospinal involves (tilting of) head-neck - activating the vestibular receptors. cervicospinal detects only neck-neck movements via stretch reflexes in the neck.
how and why does the body sensitise + amplify pain after injury?
via *peripheral sensitisation* (plastic changes in C fibers amplify signals) and *central sensitisation* (same in dorsal horn). done so it hurts even more to touch skin. this protects the area whilst it heals
how can silent nociceptors be activated?
via the axon reflex; if inflammation occurs, the chemicals released by mast cells etc may activate nociceptors so they become painful
*how* is sound a pressure wave?
vibration of objects sets up pressure waves in the surrounding air, which propagate (because air has an 'elastic' property
viral conjunctivitis vs bacterial
viral = more common + more contagious, linked to flu-symptoms, watery dischange, can damage vision. bacterial = yellow green pussy discharge, crusting in morning, not affect vision.
which are spoken at a lower pitch and higher sound, consonants or vowels?
vowels (and sadly for hearing loss patients, consonants are more important for word recognition than vowels)
which is more efficient, human walking or running?
walking (75% more than running)
which structures are critical in causing declarative memory loss in medial temporal lobe amnesia
was thought to be hippocampus and amygdala, but recently shown to be *rhinal and perirhinal cortex*
vigilance
watchfulness; process of paying close and continuous attention
what features of lightwaves enable us to form different aspects of image
wavelength = colour, light/dark edges = contrast, spatial frequency = size
amantadine
weak antagonist of NMDA glutamate receptor, increases dopamine release, and blocks dopamine reuptake. weak treatment for parkinsons
is there muscle weakness in upper or lower motor neuron lesions?
weakness is shown in both, but in upper lesions it has a specific muscle distribution (pyramidal weakness) whereas in lower lesions it affects individual muscles controlled by the lower motoneuron
pyramidal weakness
weakness of specific muscles so that flexors in the upper limb are stronger than the extensors and the reverse is true in the lower limb. seen in upper motoneuron lesion.
what is the key side effect of atypical antipsychotics
weight gain
describe oscillatory activity in a two neuron loop
when an excitatory neuron links to an inhibitory neuron and they cyclicly act on each other, causing bursts of activity and silence
what is the recency/primacy effect in memory?
when asked to remember a list of words, people are best at remembering the first and last few words.
how does lack of light affect bipolar cells
when is light, photoreceptor cells hyperpolarise and release less glutamate. this stimulates ON bipolar cells and inhibits OFF bipolar cells
refractive disorder
when shape of the eye, shape of the cornea, or condition of the lens prevents light focusing on the retina properly.
occipital alpha rhythms are seen on an EEG when?
when subject has eyes closed but awake
what is reflex adaptation? do all reflexes show adaptation?
when the body adjusts its reflex response in a certain situation - eg while spinning in the baranyi chair with eyes closed, nystagmus of head adapts (decreases), leading to several seconds of post-rotational nystagmus. *not all reflexes do this*
lissaur's tract
when the spinothalamic tract neurons enter the spinal cord, they mostly decussate at level of entry, but some may first zip up or down a couple levels in *lissaur's tract*
describe phase locking of auditory nerve
where neurons only fire at the preferred stage of a sound wave cycle. Due to long refractory periods, having combos of neurons locked at different phases enables brain to detect *frequency*
where is the junction between the peripheral + central nervous system?
where the dorsal and ventral roots arise
how do you describe the distribution of Ia nerve fibres across intrafusal muscle fibres?
'flower spray endings'
what are T1 and T2 in MRI?
'time constants' - they can be set up for each scan as a sequence, and give different shades/intensity signals forvarious tissues
stereopsis
* perception of depth* produced by the reception in the brain of visual stimuli from both eyes in combination; binocular vision
what are the DSM-5 criteria of depression?
*(1 of first 2 necessary plus 4 others) for 2 weeks: *Dysphoria (i.e. reverse of euphoria / increased negative), Anhedonia (i.e. lack of positive), Sleep changes, Altered weight/appetite, motor changes, Fatigue, Worthlessness/guilt, Lack of concentration/decisiveness/interest, Suicidal ideation
name 3 types of ganglia which presynaptic sympathetic neurons synapse with?
*paravertebral ganglia* (R+L sympathetic trunks) or *prevertebral ganglia* (ganglia anterior to vertebral column, around the abdo aorta). also (sort of) the *adrenal glands*
name 3 diseases in which alpha-synuclein aggregates?
*parkinsons disease*, lewy-body disease, multisystem atrophy
which conditions cause cytotoxic cerebral oedema?
*trauma*, reye's syndrome, hypothermia, *early ischemia*, encephalopathy, cardiac arrest, pseudotumor cerebri
pain, epilepsy, anxiety - are these schizophrenia +ve or -ve symptoms?
+ve (they are all signs of a brain which is over active)
what value is the resting potential of most cells?
-70mV
is haemophilus influenzae gram - or +
-ve
depressions, parkinsons, alzheimers - are these schizophrenia +ve or -ve symptoms?
-ve (all signs of a brain which is less active)
what is the average auditory threshold for hearing sounds of frequency 1000 Hz in a young adult?
0dB
how many cones does each retinal ganglion cell connect to?
1 (each cone gets a ganglion cell entirely to itself, unlike rods)
what is the prevalence of schizophrenia?
1%
chant to remember reflexes
1, 2 buckle shoe (achilles), 3,4 kick the door (patella), 5,6, pick up sticks (biceps), 7, 8 lay them straight (triceps)
primary somatic sensory cortex contains which brodman areas?
1,2 and 3
what age does schizophrenia usually onset?
16-24yrs
each hippocampus connects to the contralateral hippocampus via what?
2 pathways, one through the hippocampal commissure, and one through anterior commissure
is MS more common in males or females?
2:1 females:males
how long do you have to have a pain for it to be chronic?
3 months
obesity is regarded as a BMI of over what?
30
what is the mean age of onset of MS
30years
how many pairs of nerves does the CNS consist of?
43. (12 pairs cranial nerves, 31 pairs spinal).
what is the incidence of meningococcal meningitis
5 cases, 100,000
what is the only ionic monoamine receptor
5HT3
what is the frequency of alpha waves
8-13Hz
audiometry checks hearing thresholds of sounds up to which frequency? why?
8000 Hz. (humans can supposedly hear up to 20,000, but the lower frequencies are most important in daily life)
primary hypertension accounts for what % of all hypertensive cases?
90% (it is aka 'essential' hypertension)
in parkinsons, loss of dopamine causes increase in which tremor-inducing chemical?
ACh
which single transmitter is pretty much the only one used in the motor nervous system
ACh
what is the most commonly found receptor in the nervous system?
AMPA receptor
if you give NA to a healthy patient, would you expect HR and BP to rise?
BP yes - but not HR because the baroreceptor reflex fires in response to raised BP, which slows the heart
what do the letters 'C', 'Fp' and 'Cz' stand for in EEG?
C: central, Fp: Frontal pole, Cz: vertex
which 3 DNA bases are in the trinucleotide repeat of the IT15 gene? how many times do they repeat?
CAG. In healthy people, they repeat <34 times. the more repeats *over* this, the more likely/severe the *huntingtons disease*
which areas of the brain are affected by the affective/cognitive dimesions of pain?
Anterior Cingulate cortex (ACC)
which dopamine receptors activate adenylyl cyclase?
D-1 and D-5
which dopamine receptors inhibit adenylyl cyclase?
D-2, -3, and -4
how do D1 and D2 receptors couple to adenyl cyclase?
D1 = positively coupled to adenyl cyclase, D2 = negatively
how does apomorphine enable parkinsons patients to move properly?
D1 and D2 receptor agonist (acts like dopamine to restore movement)
domperidone
D2 R antagonist which doesn't cross blood brain barrier into brain. antidopaminergic drug used in general to suppress nausea and vomiting (acting on CTZ), as a prokinetic agent and for promoting lactation
Ropinirole
D2 agonist sometimes used in parkinsons
all antipsychotics antagonise which receptors
D2 dopamine
why does loss of dopamine production cause motor symptoms of parkinsons
DA action on D1 receptors is needed to enable movement (direct pathway) and DA action on D2 is needed to inhibit unwanted movements (indirect pathway)
side effects of SSRIs include
GI, rash/tremor/uticaria, loss of libido
list factors which could cause brain oedema
Infarction ("ischaemic stroke")- Brain trauma- Abscess, purulent meningitis.- Hypoxemia- Hyponatriemia
causes of cytotoxic oedema
Ischemia (acute), Hyponatremia, Reye's Syndrome, purulent Meningitis
what is brodman area 6?
Premotor cortex and Supplementary Motor Cortex
give 6 symptoms of meningitis
Headache Photophobia Nausea/vomiting Neck stiffness (Rash) (Fever)
which are the biggest fibres involved in the muscle spindle system?
IA fibres
SNRI
Serotonin-norepinephrine reuptake inhibitors. antidepressants which inhibit reuptake or serotonin *and NA* from synapses
rarefactions
a decrease in the density of something, eg a soundwave or a tissue
paraesthesia
abnormal sensation, typically tingling or pricking ("pins and needles"), caused chiefly by pressure on or damage to peripheral nerves
what is the lifetime prevalence of depression?
about 25%
how might a brain stem lesion present in terms of *visual* symptoms
affecting eye motility; internuclear ophthlmoplegia, nystagmus
which systems form affective behaviour?
affective behaviour is formed by combined characteristic patterns of autonomic + somatic activity
which nerves supply the afferent and efferent limbs of the pupillary light reflex
afferent is within CN II (optic nerve). efferent within CN III (occulomotor).
type 1 synapses
aka asymmetric synapses. rounded vesicles in the presynaptic cell and a prominent postsynaptic density. typically excitatory + found between axons and dendritic spines
dorsolateral tract of lissauer
aka dorsolateral tract. strand of grey matter posterior to dorsal horn, associated with pain/temp and having many unmyelinated axons
Pick's disease
aka fronto-temporal lobe dementia. dementia which is more likely to affect behaviour/language/personality due to build up of tau proteins in frontal brain. often caused by mutation in MAPT (tau gene)
glia limitans
aka glial limiting membrane. thin barrier formed by astrocyte foot processes, surrounding brain and spinal cord, deep to the pia mater. prevents overmigration of neurons/neuroglia into meninges, and helps regulate molecule/cell transport along with blood brain barrier
neocortex
aka isocortex. largest part of the cerebral cortex (includes most of it except olfactory + limbic areas). has 6 layers.
spectogram
aka sonogram. visual representation of the spectrum of frequencies in a sound or other signal as they vary with time (eg you can 'see' pitch)
tentorial notch
aka tentorial incisure. the space in the tentorium through which the brainstem passes
function of pupil
allows light to enter eye
neuroleptics
another name for antipsychotics
what is the most common refractive disorder?
astigmatism
vestigial
atrophied / having become functionless in the course of evolution
BOLD-contrast imagine
blood oxygen level dependent imaging; method used in fMRI to observe areas of the brain which are *active* by identifying areas with *decreased* deoxyhaemoglobin than oxy-Hb
what does the cornea cover?
both the pupil and the iris (is then continuous with the *sclera* which covers the rest of the eyeball)
causalgia
burning pain in a limb along the course of a peripheral nerve; usually associated with skin changes
how is magnitude of a sensory stimuli encoded in the nervous system?
by AP *frequency*. (above a threshold of a stimulus pressing on skin, a sensory receptor potential excites a train of all-or-nothing action potentials, whose frequency varies with stimulus strength)
how are cutaneous mechanoreceptors classified?
by adaptation properties, structure, + location (superficial or deep).
what is the posterior boundary of the frontal lobe?
central sulcus
ACh is synthesized by which enzyme?
choline acetyl transferase
why are non-selective MAO inhibitors not preferred
choosing a selective MAO A or MAO B inhibitior preserves one MAO type to break down *tyrosine* (prevents hypertensive crisis)
describe the flow of CSF
choroid plexuses in lateral ventricles, interventricular foramen, 3rd ventricle, cerebral aqueduct, median+lateral apertures, subarachnoid space, (central canal etc), arachnoid granulations in superior sagittal sinus, bloodstream
3 'C's which you need to describe the optic disc
colour, contour, and cup-to-disc ratio (cup is central white portion)
are there more rods or cones in the fovea?
cones
lens accomodation
contraction of the ciliary muscles which relieves the tension on the zonule fibres, allowing the lens to become rounder due to its natural elasticity
pyramidal tract is AKA?
corticospinal tract (and some corticobulbar tracts)
why do you feel sick when your vestibular system and visual system are mismatched (eg seasickness)?
could be a reflex to do with certain edible toxins/poisons being associated with fever + dizziness.
what is the effect of isoflurane (and other halogenated anaesthetics) on sympathetic outflow?
decrease it
does L-DOPA therapy increase or decrease blood pressure? why is this surprising?
decrease. surprising because L-DOPA can be coverted to NA, so you would expect a sympathetic increase
amblyopia
decreased vision in an eye that otherwise appears normal, often due to 'turned off' visual processing in the brain. aka *lazy eye*
what is the pathogenesis of axonal damage
diffuse axonal injury eg brain trauma, tissue damage eg tumours, infarction
micturition
discharge of urine
3 neurotransmitters associated with schizophrenia
dopamine, seratonin, NA
naloxone
drug which blocks opiates receptors (given to addicts who overdose)
anxiolytic
drug which reduces anxiety
triptans
drugs which relieve pain in migraines/headaches
what does the word 'vestibule' mean
entrance chamber
firefly luciferase
enzyme which allows fireflies to produce light. binds *hydrophobic* molecules
what is RAPD in the eye
Relative afferent pupillary defect
how can you quickly determine whether a patients incoordinated movements are due to sensory ataxia or something else (like cerebellar pathway lesion)?
Rombergs sign: does patient lose their balance when they close eyes. if so, its sensory ataxia
plantar flexion reflex has which nerve roots?
S1
which part of the brain controls circadian rhythm
SCN (suprachiasmatic nucleus)
paroxetine
SSRI antidepressant, highly potent for blocking SERT
EC50
'effective dose' - the dose or amount of drug that produces the desired effect in 50% of the subjects taking it
prosopagnosia
'face blindness'. unable to recognise/perceive faces, while other aspects of visual processing and intellectual functioning remain intact
working memory
'ready to use' info - may be new sensory information, or info retrieved from long-term storage (episodic/semantic) ready to access (e.g. where you parked your car whilst in the supermarket).
egocentric space
'space as I see it' eg moving hand to the left (as opposed to allocentric space)
'angio-' means what?
'vessel'
william james
father of psychology; first hypothesised that memory involved carving out of 'brain-paths' by excitation in the brain
what does Beck's term 'Cognitive distortions' mean?
faulty logic, e.g. overgeneralisation, selectively filtering out positive information
mandibular nerve travels through which skull foramen
foramen ovale
where do the pyramids of the corticospinal tract split into bundles?
in lower pons
which cranial fossa does the brainstem lie in?
inferior cranial fossa
what does IT15 stand for?
interesting transcript 15
how is amphetamine related to ecstasy?
it is the parent drug
what does the amplitude of an EEG wave indicate?
large amplitude = synchronised neurone activity summating
where in brain are visual memories 'stored'
lateral temporal lobes
sensory ataxia
lesions of sensory nerves or pathways deprive the brain of proprioceptive/sensory info needed for coordinated movements. sufferers show a positive *Rombergs sign*
would there be more or less signal from the substantia nigra in a scan of a parkinsons patient?
less
is brain more or less active during sleep than when awake?
less active, except for REM sleep, when it is more active
in transverse sections of spinal cord, is white matter more or less in lower spinal sections?
less and less white matter relative to grey as you move down the spinal cord (because there are fewer ascending/descending pathways)
why does the STN increase its firing in parkinsons?
less dopamine means less firing of D2 receptors,
difference between hippocampus proper and hippocampus formation
"hippocampus proper" refers to the four CA fields, and "hippocampal formation" to the hippocampus proper plus dentate gyrus and subiculum
which has a better prognosis, supra- or infra-tentorial space occupying lesion? why?
supratentorial. there are more preceding signs (confusion/stupor/vomiting) than in infratentorial lesion (often produces coma without preceding signs)
supraventricular vs ventricular arrhythmias
supraventricular arrhythmias are either atrial or junctional; ventricular affect the ventricles.
How does MS present?
symptoms start typically between 20-40yrs old, separated in time and space. episodes of *numbness*/tingling/*pain* sensations. lhermitte's sign. optic neuritis/internuclear ophthlmoplegia. balance/speech/bladder erectile problems. *weakness, maybe worse after a hot bath*. depression, cognitive/memory problems.
phencyclidine
synthetic NMDA receptor antagonist, used as an anesthetic by vets; illicitly taken as 'angel dust' for its effects as a hallucinogen
methadone
synthetic narcotic drug similar to morphine but less habit-forming; used in narcotic detoxification and maintenance of heroin addiction
function of emotions
tell us what we want more/less of; we can make complicated decisions without having to reason things out
primary auditory cortex is in which lobe?
temporal
apnea
temporary cessation of breathing, especially during sleep
concussion
temporary unconsciousness after a blow to the head; mechanisms unknown - but some sort of 'brain shock'
preseptal cellulitis of eyelids
tender/warm erythematous upper + lower eyelid skin associated with cold/fever + common in children
what lies between the occipital lobes and the cerebellum?
tentorium cerebelli
psychic blindness
term used by researches in 1940s to describe monkeys with temporal lobe lesions who kept picking up inedible objects to their mouths - due to damaged visual pathway object recognition
what does the nernst equation calculate?
the reversal (aka equilibrium) potential of an ion
is the red nucleus in the midbrain, pons, or medulla
the rostral midbrain
blood/air coefficient is AKA
the solubility of a gas in blood
which areas of the brain are affected by the discriminative dimension of pain?
the somatosensory cortex
second order somatosensory neurons terminate where? what do they synapse with?
the thalamus (mosly *ventral posterior nucleus*) to synapse with 3rd order neurons which run to the somatosensory cortex
why is healing minimal in osteoarthritis?
the tissue which is damaged is cartilage; a tissue with little capacity to heal itself
how are ACE inhibitors teratogenic?
they cause renal damage in baby
how does deep brain stimulation treat parkinsons?
two deep stimulating electrodes create a tetanic block of action from subthalamic nucleus, preventing the STN from increasing the inhibitory drive on the thalamus from the basal ganglia outputs.
how do experiments prove that threat increases pain?
two patient groups have foot lasered. one group told it will be fine, another group told that 'the ethics board had some reservations with this, but we're doing it anyway.' 2nd group feel more pain
barbituate
type of CNS depressant drugs which can produce a wide spectrum of effects, from mild sedation to total anesthesia (eg thiopentone). not often first choice drugs (resp.depression, not analgesic, addictive, narrow therapeutic index, deadly)
transient global amnesia
type of amnesia produced by small interruptions in cerebral blood flow - involves short retrograde + anterograde amnesia for *minutes/days* (no permanent damage)
implicit memory
type of memory in which previous experiences aid in the performance of a task without conscious awareness of these previous experiences. includes procedural and emotional memory
name the rate limiting enzyme for NA synthesis?
tyrosine hydroxylase
autonomic dysreflexia
uninhibited and exaggerated reflex of the autonomic nervous system to stimulation - sudden high BP - medical emergency. often seen in patients with spinal injuries above T6
give some somatic symptoms of depression
unintentional weight change, fatigue, (appetite/sleep disturbance), aches&pains
why are C nerve fibres so slow at impulse conduction?
unmyelinated, small diameter
does the switch from conscious to unconscious occur over a wide or narrow concentration range of anaesthetics?
very narrow concentration range. the concentration-response curve is very steep for anaesthetics compared to other drugs
what has amphetamine got to do with dopamine?
very potent dopamine releasing agent; 'dopamine pours out into brain.'
tritanopia
very rare colour blindness in which there are only two types of cones present (no blue cones) in the retina, causing green/blue confusion
does schizophrenia lead to split personalities?
very rare to lose sense of own identity.
VMAT2
vesicular monoamine transporter. integral membrane protein that transports monoamines (DA, NA, 5HT, H) from cellular cytosol into synaptic vesicles
inferotemporal cortex is associated with 'storing' what kind of memories?
visual memories, eg identifying objects and faces
the action potential threshold is reached *when*?
when Na+ influx > resting K+ efflux, and depolarisation due to Na+ influx is sufficient to activate neighbouring Na+ channels
is capsula interna white or grey matter
white
do veins have sympathetic tone?
yes (in fact it is quite substantial - is what prevents postural hypo-tension)
will an unconscious patient have a pupillary light reflex?
yes (unless their brain has swollen or brainstem damaged)
is huntingtin protein found in healthy people?
yes - it is important in healthy life, though if mutated, it is the protein which causes huntingons
can amnesia patients be classically conditioned?
yes - not impaired on skill memory/priming tasks
is the mammillary body a paired structure?
yes - there are two just posterior to infundibulum
is it possible for radial glial cells to undergo symmetrical division?
yes - they can just form two more RGcells. however, importantly, they can undergo asymmetric divisions.
is depression heritable?
yes - unipolar is 30 to 50% heritable, and bipolar is around 80% (similar to schizophrenia)
are strong opiods effective at treating cancer pain?
yes they are largely effective (not as effective as in acute pain, however).
is CBT a recommended treatment for pain?
yes, cognitive behavioural therapy is recommended as first line treatment in chronic pain
are mechanoreceptors, thermoreceptors, and nociceptors myelinated?
yes, except C fibre nocicptors
is it possible to have a negative auditory threshold?
yes, in better than average hearing - points plotted at -5 or -10dB mean you can hear quieter sounds than the average population used to create the ISO (which calibrates a 'normal' threshold seen at 0dB.)
does location affect severity of drug withdrawal?
yes, in places associated with drug, addicts will have worse withdrawal symptoms
are AChE inhibitors used in closed-angle glaucoma?
yes, they can be in both, as they act to constrict pupil. it is a2 agonists (epinephrine/diperiprine) which you would contraindicate in closed-angle glaucoma, as they are mydriatic so would worsen closed angle
can fruit flies be trained?
yes, they can learn by classical conditioning
why does opening more ion channels in a membrane decrease resistance of that membrane?
you can think of it as the resistance of the membrane to passage of ions - opening more channels will decrease this resistance.
why do you get *dose escalation* and *addiction* with barbituates
you develop metabolic tolerance to barbituates
where do you find fibroblasts/collagen in the CNS?
you don't
what is different about the nernst equation with negative ions rather than positive?
you take ln(inside conc of ion/outside conc of ion)
how can you tell whether sounds come from left or right, front or back?
your brain uses the time delay between sounds hitting your right ear to your left to decide whether sound comes from L/R. front and back sounds hit both ears at the same time - pinna is shaped to help distinguish them
lenticulo-striate arteries
~10 long penetrating arteries which branch upwards from the initial part of the MCA, supplying basal ganglia + much of internal capsule. sensitive to rupture/obstruction, leading to sterotyped stroke symptoms
how many muscle spindles in the body?
~20,000
what is intracellular pH?
~7.2
how often does the olfactary bulb regenerate?
~once a month (one of only areas of continuous neuroregeneration)
what are class II anti-dysrhymic drugs? give examples
β-blockers. metoprolol, timolol, propanolol, alprenolol
what does GABA stand for?
γ-aminobutyric acid
retrograde amnesia
loss of memory for events *prior to the trauma*
name the region of greatest visual acuity in the eye
macula
why do you get vein occlusions?
mainly due to high BP causing arterioles to become thickened/ridged. arterioles then press onto veins
dorsal column decussate at the medulla or the level of spinal cord?
medulla
prestin
motor protein of the outer hair cells of cochlea. it changes shape as the voltage around it changes - causing whole cell to change in length
nasal hemi-retina
nasal half of the retina
can you see the pterygoid canal in a skull?
no (hidden from view) but it can be seen in a disarticulated sphenoid bone
2 main causes of dry eyes
not producing enough tears, or rapid evaporation of tears (due to not enough secreted lipid from glands)
which mesodermal structure is involved in 'telling' the ectoderm to form the nervous system/morphogenesis of spinal cord?
notochord
primary visual cortex is in which lobe?
occipital
what % of parkinsons patients have a mutation which causes parkinsons?
only 10% (rest of patients we don't know the cause)
how many axons can a single neuron have?
only ever *one*. (this may have collaterals which contact many other
is the fasciculation in upper or lower motor neuron lesions?
only lower
which receptor does morphine bind to?
opioid receptors, particularly μ-opioid receptors
the circle of willis surrounds what?
optic chiasm
where do fibres from the nasal retina decussate?
optic chiasm
blood vessels radiate from which part of the retina?
optic disc
origin and insertion of ciliary muscle
origin: scleral spur(longitudinal fibres)/root of iris(circular fibres). attach the end of ciliary processes/root of iris.
tectospinal tract
originates in superior colliculus of midbrain tectum. controls movements of the head/neck/eyes at the level of C1 vertebra, in response to visual/auditory stimuli
if a fracture of petrous temporal bone occurs, would you expect rhinorrhoea or otorrhoea?
otorrhoea (leakage from the ear) potentially of CSF which escapes into ear through any cracks
which cells help amplify vibrations of the basilar membrane?
outer hair cells
which ear hair cells function to enhance sensitivity to sound?
outer hair cells
what pathology could give rise to a 'sympathetic overdrive' seen in a patient?
over-production of adrenaline by Pheochromocytoma (type of adrenal gland tumour)
what causes compulsive behaviours as a side effect of parkinsons treatment?
overactive reward system caused by treatment which increases dopamine
allodynia
pain due to a stimulus which does not normally provoke pain. Temperature or physical stimuli can provoke allodynia, and it often occurs after injury to a site
neuropathic pain
pain generated by lesion or disease to nervous system (usually somatosensory system)
gate control theory of pain
pain is influenced by ascendingna dn descending influences, controlled by the spinal chord
difference between pain and nociception
pain is the *percept*, nociception is what pain receptors detect
silent nociceptors
pain receptors which only respond to mechanical stimuli when inflammatory molecules are present
what important difference should doctors remember about difference between painful and painless visual loss?
painful = usually 2nd to vascular events, whereas painless is usually 2nd to inflammatory events
anterior ischaemic optic neuropathy
painless loss of vision due to damage to the optic nerve from insufficient blood supply
is central retinal artery occlusion painful or painless?
painless visual loss
which bone is found deep within the pterygopalatine fissue
palatine bone
Edinger-Westphal nuclei
parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle. aka 'accessory oculomotor nucleus'
primary somatosensory cortex is in which lobe?
parietal
optic ataxia is associated in lesions where in the brain?
parietal cortex
primary visual cortex
part of occipital lobe, responsible for first processing visual information. one on each side - deal with R and L visual fields respectively. cortical blindness if loss of both.
anterior spinocerebellar tract
part of the somatosensory system ; runs parallel to posterior spinocerebellar tract, up the lateral outer edge of spinal cord. conveys unconscious proprioceptive info from the body to the cerebellum
amnesia
partial/total loss of memory due to damage to medial temporal lobes / limbic system
modality
particular mode in which something exists or is experienced or expressed
what is affective behaviour?
pattern of behaviour that is elicited by "emotions" such as fear, rage, surprise, disgust, anxiety, euphoria, pleasure, sadness et
dissociated sensory touch
pattern of neurological damage caused by a lesion to a single afferent tract - involves selective loss of fine touch and proprioception without loss of pain and temperature, or vice versa
streptococcus pneumoniae is aka?
pneumococcus
what does PM stand for in the brain?
premotor area
which cortex is located in the precentral gyrus?
primary motor cortex
what is function of brodmann areas 1, 2, and 3
primary somatosensory cortex - main sensory receptive area for sense of *touch*. receives from thalamus, processes info, sends to somatosensory association cortex
thrombolysis
process of breaking up and dissolving blood clots
why is 50% N2O given to women during childbirth?
produces analgesia and slight anaesthia
tau protein
proteins that stabilize the microtubule cytoskeleton, abundant in the CNS. if hyperphosphorylated, form tangles of filaments (NFTs), which lead to neurodegenerative diseases, mainly alzheimers
which are found nearer the midline, the motor neurons for proximal structures, or for distal structures?
proximal
difference between psychological and physical drug dependence
psychological affects mood / behaviour, physical affects somatic physiology
the pterygoid canal and foramen rotundum both lead from the posterior sphenoid bone, right through the sphenoid into the?
pterygopalatine fossa
which have capsules, slow or rapid adapting mechanoreceptors?
rapid (eg pacinian and meissner corpuscles)
paroxysmal disorder
recurrent, episodic condition eg narcalepsy, epilepsy, migraine
circadian
recurring naturally on a twenty-four-hour cycle, even in the absence of light fluctuations
conjunctivitis
red inflammation of the conjunctiva, caused usually by adenovirus or sometimes bacteria (if the latter, there will also be sticky pus)
central sleep apnea
reduced central respiratory drive to the diaphragm during sleep. Reduced muscle tone in non-REM sleep leads to reduction of airways. resulting hypoxia + hypercapnia wake the patient
fixation reflex
reflex concerned with attracting the eye on an object. For example, when a light shines in the periphery, the eyes shift gaze on it
frontal eye field
region in frontal cortex called Brodmann area 8 which communicates with extraocular muscles. reponsible for saccadic eye movements for visual field perception, and for voluntary eye movement
ventral striatum
region of brain involved in 'prediction error' - releases phasic dopamine bursts which correlate with people discovering that something they believed is not true - eg the sweets are no longer in same place in supermarket
intermediolateral cell column
region of gray matter found in Rexed lamina VII of the spinal column, which forms the lateral horn
tegmentum
region of gray matter on either side of the cerebral aqueduct/running down the brainstem
Wernicke's area
region of the brain concerned with the comprehension of language, located in the cortex of the dominant temporal lobe
wernike's area
region surrounding auditory cortex; involved in understanding the 'meaning' of words. confined to the left (dominant) hemisphere
define: reticulate
resembling or forming a network
phenotolamine
reversible nonselective alpha-adrenergic antagonist
which is more sensitive to photons, rods or cones?
rods
what are SA2 receptors?
ruffini endings: deep mechanoreceptors
give some behavioural symptoms of depression
self-neglect, sleep disturbance, psychomotor agitiation/retardation (low motivation)
give 3 main functions of the enteric NS
sense changes in lumen/distension, control contract/relax/peristalsis for movement of gut contents, control absorption/secretion.
anti-tussive
stops coughing
heteroporia is AKA
strabismus
intraparietal sulcus
sulcus on postero-lateral brain: divides parietal lobe into superior and inferior nodules. involved in visual and numerical abilities
where are Mu-opioid receptors found on the spinal cord?
superficial dorsal horn - specifically the substantia gelatinosa seen in yellow
which theory explains why in amnesia (hippocampal damage), semantic memories are often spared over episodic memories? why?
*multiple trace theory.* semantic memories are used often (encoded many times) compared to the one trial encoding of episodic memory, hence semantic are more linked to the cortex and protected in hippocampal damage
radiculopathy
*nerve root* damage results in pain, weakness, numbness, difficulty controlling specific muscles... all in the region of that nerve distribution
entrapment neuropathy
*peripheral nerve* damage (by ribs or fibrous bands etc) results in pain, weakness, numbness, difficulty controlling specific muscles... all in the region of that nerve distribution
hyperopia
*refractive disorder*. (farsightedness): difficulty in seeing close objects clearly
myopia
*refractive disorder*. (nearsightedness): difficulty in seeing distant objects clearly
astigmatism
*refractive disorder*. blurring of vision caused by a cornea that is oval shaped, rather than round. Often found in conjunction with cases of myopia or hyperopia
presbyopia
*refractive disorder*. means "old eye". reduced elasticity of the lens due to normal aging process. affects ability of the eye to focus on close objects
why do APs only propagate in one direction?
*refractory period.* Na+ channels inactivate briefly after being opened, which means the membrane behind the action potential won't be activated by the local ion/voltage changes. also, this previous membrane is hyperpolarised by a K+ efflux after AP, so threshold is further to reach.
name 5 atypical neuroleptics
*risperidone*, Clozapine, Paliperidone, Olanzapine, Qietiapine
what are the 3 dimensions of pain
*sensory/discriminative* - quality + location. *primary affective/cognitive dimension* - unpleasantness, distress, fear, want it to stop *secondary affective/cognitive dimension* - anxiety + depression
name some supraventricular arrythmias
*supraventricular tachyarrhythmias* (SVTs) eg sinus tachycardia, atrial ectopic beats, atrial tachycardia, atrial fibrillation, wolff-parkinson-white, lown-ganong-levine. *(SVBs)* eg atrial sinus bradycardia, 1st, 2nd, 3rd degree atrioventricular block
define *borderline* hypertension
*sustained* bp > 140/90 mmHg
define *benign* hypertension
*sustained* bp > 160/100 mmHg, with no clinical features
list 7 *physical* symptoms of clinical depression
- Altered sleep: insomnia or increased sleep - Changes of appetite/weight - Fatigue / lethargy - Headaches - Unexplained aches or pains - Reduced libido - Digestive problems e.g. constipation
list 4 *cognitive/behavioural* symptoms of clinical depression
-Increase in negative/suicidal thoughts - Difficultly concentrating/remembering/making decisions - Anhedonia - Withdrawal from social activities
list 4 *emotional* symptoms of clinical depression
-Long-lasting low mood - Feelings of worthlessness, hopelessness, helplessness, guilt, regret, self-hatred - Low confidence / self-esteem - Anger / irritability
name the 5 key dopamine pathways
1. Nigro-striatal; A9 - caudate/putamen (motor function) 2. Mesolimbic; A10 - nucleus accumbens (reward) 3. Mesocortical; A10 - frontal cortex (psychosis) 4. Median eminence; pituitary (prolactin secretion) 5. Chemoreceptor trigger zone (CTZ) (vomiting)
how long from diagnosis do most MND patients live for?
1-5 yrs (mind you, stephen hawking managing over 50 yrs!)
how long after onset will MS patients require assistive walking device
15 years
what is the minimum % of O2 required in inspired air
15%
how many dendritic spines are on each MSN?
15,000
normal pressure of CSF
18mm
Vaughan-williams classification
1970s classification of antidysrhythmic drugs, with classes from I to IV based on their effects. sadly is a bit old now; many drugs span multiple classes
below T6, there are how many dorsal column tracts each side of the spinal cord?
2
how many ACh molecules bind to a nicotinic receptor to open it?
2
what kind of nuclei are contained within the colliculi on the dorsal midbrain?
2 superior colliculi = visuo-motor nuclei. 2 inferior colliculi = auditory relay nuclei
antihistamines bind to which receptors? what does this do?
2 types of antihistamines: either block H1 to treat allergies/insomnia, or H2 to block gastric acid secretion from parietal cells
what percentage of people with depression attempt suicide? what percent succeed?
20% attempt, 5-10% succeed (some use their medication)
paravertebral ganglia
23 paired sympathetic ganglia either side of the spinal cord, aka the sympathetic chains/trunks.
thalidomide taken during which days of gestation was most likely to cause phocomelia maximal?
24-27 days
how long after onset will MS patients lose ability to walk?
25 years
internal arcuate fibres
2nd order neurons that arise in the cuneate and gracile nuclei and pass across the midline of the medulla oblongata. once decussated, they are renamed 'the medial lemniscus'
what are the divisions of the ANS?
3 divisions - enteric, sympathetic, parasympathetic
the VPL projects to which brodmann areas?
3, 1 and 2 (primary somatosensory cortex)
P type cells feed into which layers of the lateral geniculate nucleus?
3,4,5 and 6
what percentage of osteoarthritis sufferers feel knee pain?
39% with grade 2 OA, 61% with grade 3/4 (pain is not inevitable feature of OA)
what is the normal white cell count of CSF
4
what % of schizophrenia patients attempt suicide?
40%
what is the fatality of meningococcal meningitis?
5% if in meninges, 20% if causes meningococcal bacteraemia, in which case is 20%)
neurons of the raphe nuclei contain which neurotransmitter?
5-HT
Buspirone
5-HT1A agonist used mainly in USA which has antidepressant and maybe some anti-anxiety effects. takes weeks to see its effect
roughly what % of all axons in CNS cross the midline?
50%
basal ganglia haemorrhage is commonly caused in which age group?
50s - 60s (by hypertension)
Alzheimers disease is what percentage of dementia cases?
55%
are 5HT receptors ionotropic or metabotropic?
5HT1 and 2 are *metabotrophic*, 5HT3 is *ionotropic*
which is better, 6/6 vision or 6/12?
6/6 (means you could read up to the '6m' line on snellen chart, rather than the '12m' line)
temazepam effects wear off after aprrox how low?
8hrs
what % of basal ganglia neurons are GABAergic?
99%
how can oligoclonal bands be used to test for MS?
>90% of MS patients, the CSF contains oligoclonal bands *not present in blood serum*.
which fibres cause you to immediately withdraw from a very hot stimulus
A-delta sensory fibres (the fast nociceptive fibres)
paracentral lobule
A gyrus on the upper medial surface of each cerebral hemisphere, behind the medial frontal gyrus and above the cingulate gyrus. forms the continuation, from the lateral brain surface, of the motor + sensory gyri: contains cortical areas representing the lower leg, foot, toes, bladder, rectum, and genitalia
what parts of the homunculus does the middle cerebral artery supply?
everything except lower limb
hyperaemia
excess of blood in the vessels supplying an organ or other part of the body
narcolepsy
excessive daytime sleepiness where there may be attacks of REM sleep/cataplexy, caused by reduction in hypothalamic orexin neurons
Aneurysm
excessive localized enlargement of an artery caused by a weakening of the artery wall
obstructive sleep apnea
excessive relaxation of pharyngeal muscles occludes the airways, especially in overweight men
neoplasia
excessive, uncontrolled growth of tissues, forming benign or malignant tumour(s)
does the striatum receive excite or inhibitory input from cerebral cortex?
excitatory
is substance P peptide excitatory or inhibitory neurotransmitter?
excitatory
difference between gray type I and II synapses?
excitatory (gray type I) is much darker and more fuzzy due to glutamate receptors, with characteristic spherical vesicles. inhibitary (gray type II) is thinner with vesicles of different shapes eg cylinders
perforant path
excitatory pathway from mainly layer 2 *entorhinal cortex* to dentate gyrus and CA3 of *hippocampus*. important in spatial memory learning, memory consolidation
in general, do activated alpha and beta 1 receptors have excitatory or inhibitory effects?
excititary
what is the function of brodmann area 4
execution of motor commands
is there risk of addiction giving opiates to chronic pain patients?
experimentally, it seems that the rewarding effects of opiates disappear when pain is present - so it seems that there is little risk.
medical name for a stye
external hordeolum
function of rubrospinal tract
extrapyramidal (involuntary) movement - eg coordination
reticulospinal tract
extrapyramidal descending tract from reticular formation, important in postural/locomotive control of upper body
vestibulospinal tract
extrapyramidal motor tract from vestibular nuclei in brainstem to ipsilateral muscles. involved in posture and balance.
4 main ions involved in resting membrane potential
K+, Na+, Cl-, and to an extent Ca2+
what are class III anti-dysrhymic drugs? give examples
K+channel blockers. amiodarone, sotalol
chorea can be a long term side effect of which drug?
L-DOPA
dystonia can be a long term side effect of which drug?
L-DOPA
levodopa is aka?
L-DOPA
which drug is normally used to treat parkinsons
L-DOPA
verapamil
L-type calcium channel blocker used to treat hypertension, angina, arrhythmia, migraine
knee extension reflex has which nerve roots?
L3,L4
laterodorsal tegmental nuclei
LDT nuclei: found in the tegmentum of the brainstem. Send cholinergic neurons to many forebrain targets eg thalamus, involving them in alert/attentiveness, and generate REM sleep
which is more soluble in blood, isoflurane or nitrous oxide?
isoflurane (N2O not very soluble in blood)
which factors could cause an obstruction in intracranial CSF drainage
Circulation: obstructive tumour, resorption- Malresorptive: haemorrhage, meningitis, high CSF protein
name the chief inhibitory neurotransmitter in humans
GABA
describe the grades of opiate abstinence
*from 0 to 3.* grade 0: drug craving/seeking/anxiety. 1: yawning/sweating/runny eyes+nose/restless sleep. 2: pupil dilation/gooseflesh/twitching/hot+cold flushes/shivering/aching/no appetite 3: insomnia/fever/high HR+BP+resp rate/abdominal cramps/vomiting/diarrhoea/weakness/weight loss
EGFR
(Epidermal growth factor receptor). Cell surface receptor which when mutated into overexpression, leads to uncontrolled cell division + cancer
give the 3 causative agents you would predict in a cause of neonatal meningitis
(GEL) group B streptococcus, listeria monocytogenes, E.Coli
IDH
(Isocitrate dehydrogenase). key enzyme in part of krebs cycle which when mutated, causes methylation of DNA histones, causing epigenetic changes linked to certain brain tumours.
which 2 structural features increase potency of anaesthetics
*halogen substitution* and presence of an *ether group*
name 5 bacteria which commonly cause meningitis
(SMILE) streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, Listeria monocytogenes, Mycobacterium tuberculosis
describe how exciting D1 neurons increases firing rate of thalamus
*increases* firing of D1 neurons --> more inhibitary drive on the internal globus palludis/substantia nigra --> less inhibitory drive from these places to the thalamus. (*disinhibition*)
what were intravenous anaesthetics developed for
*induction* of anaesthesia
cranial (so parasympathetic) preganglionic neurones travel with which cranial nerves? what are their targets?
*Vagus (X)*: lungs, heart, stomach, small intestines, liver- *Occulomotor (III)*: pupil size, lens strength- *Facial (VII)*: salivary glands- *Glossopharyngeal (IX)*: smooth muscle + glands of throat, viscera of thorax + abdomen
which kinds of agents usually cause meningitis?
*bacteria,* viruses (*enteroviruses*), fungi (cryptococcal neoformans. can be non-infectious - cancer, autoimmune (SLE)
3 main types of sensory input to the spinal cord
*cutaneous* eg touch, pain. *proprioceptive* eg muscle length. *visceral* eg enteric pain, arterial O2.
name 6 inhaled anaesthetics used today
*desflurane, sevoflurane, isoflurane, nitrous oxide*, halothane, enflurane
difference between direct and indirect pathway in connects of the striatum
*direct* produces movement (inhibits the inhibitors of thalamic neurons) + goes via the medial part of the globus palludis. indirect inhibits movement (activates inhibitors of thalamic neurons) + goes via the external globus palludis and subthalamic nucleus
how do you classify symptoms of psychosis?
*+ve (type 1) symptoms* eg auditory hallucinations, thought disorder, delusions, thought broadcasting. *-ve (type 2)* eg lack of drive, withdrawal, catatonia. *also impaired cognition* eg working memory/planning/problem solving
how do CPGs produce an alternating action?
*Central Pattern Generators* produce rhythmic patterned outputs without sensory feedback. is thought that two spinal neurons are interconnected with inhibition from each to the other; one inhibits the other until it 'runs out', at which point the other inhibits the first one until that runs out
CTZ
*Chemoreceptor trigger zone*; area of the medulla that receives inputs from blood-borne drugs/hormones. communicates with the *vomiting center* to initiate vomiting
difference between learning, memory, and retrieval?
*Learning* is the acquisition of new information/knowledge. *Memory* is the retention of learned information. *Retrieval* is necessary to recall stored memories.
how long does it take from light hitting retina to form a visual percept in visual cortex?
100 mseconds (quite slow for neurological time - hence we have alternate reflex pathways)
a 20 decibel increase = what increase in power?
10x power (relative loudness) increase.
what % of UK GP consultations are related to eyes?
1.5%
break down the proportions of depression sufferers which do/don't respond to drug treatment. how does this change in relapses?
1/3rd respond to 1st line treatment, 1/3rd response to something else eventually...and 1/3rd don't respond. each relapse, responsiveness decreases
what % of MS patients remain unimpaired without therapy for 20years after onset?
10 - 20%
which cranial nerves originate in the brainstem?
10 of the 12 pairs; III to XII.
what amount of alcohol can be teratogenic?
10 units per week - or a single binge - can cause foetal alcohol syndrome
how long after onset will MS patients lose job
10 years
which has larger diameter, Aα or Aβ fibres?
Aα
describe PNS afferent sensory fibres (the 4 classes)
Aα - large fibres from proprioreceptors, Aβ - smaller fibres from skin mechanoreceptors: touch, Aδ - even smaller fibres from fast pain/temp receptors, C - tiny fibres carrying pain, itch, temp
types of Ia (primary afferent) fibres
Aβ fibres, Aδ fibres, C fibres
which conduction velocity class of fibre are thermoreceptors?
Aδ (A-delta)
subgenual anterior cingulate cortex
Brodmann area 25. part of cortex in which increased AND decreased activity has been linked to depression - many serotonin receptors found here.
give 6 types of anti-anxiety drugs
Bromides, antidepressants (SSRIs), sedative/hypnotics (Alcohol, Chloral hydrate, Pentobarbitone, Meprobamate, Benzodiazepines)
what info does a lumbar puncture give?
CSF pressure, presence of blood (sub-arachnoid haemorrhage), infection, immune diseases eg MS, tumour cells
which uses more ionising radiation, CT or MRI?
CT (MRI uses no ionising radiation)
which enables you to see calcifications in vessels, DSA or CT angiography?
CT angiography
what are the limitations of MRI?
CT better for bone• Pacemakers & ferromagnetic implants contraindicated• Claustrophobic & noisy• Not as readily available & more expensive that CT.
which tools do we have for brain imaging
CT-MR-Angio, Conventional MR, DWI, fMRI
which of these ions are more concentrated outside the cell than inside: Ca, K, Na, Cl?
Ca, Cl and Na
what are class IV anti-dysrhymic drugs? give examples
Ca2+channel blockers. verapamil, diltiazem
give 2 Anti-dysrhythmic drugs which *aren't* in the Vaughan-William's classification
Cardiac glycosides (digoxin) and adenosine
what does CT stand for in CT scan
Computerised tomography
functions of the ANS
Control the activity of the internal organs, blood vessels and superficial structures in the skin• Maintain the internal body environment, responding to internal + external changes
problematic effects of L-DOPA
Dyskinesia• On-off effects• Psychosis• Nausea• Reduced prolactin
Full visual field
FVF: the whole area viewed by the eyes
benefits of atypical neuroleptics
Fewer EPS, reduce both Positive AND negative symptoms, help drug-resistant psychosis, Less tardive dyskinesia
what is the fastest acting 'emergency' diuretic used in hospitals?
Furosemide
describe the anatomical steps in the pathway for memory formation from the hippocampus
Hippocampus > fornix > mammillary bodies > anterior nucleus of thalamus > cingulate cortex
what does MHRA stand for?
Medicines & Healthcare products Regulatory Agency (government body)
name 5 anxiety disorders
Panic disorder (debilitating fear attacks), phobia, Obsessive Compulsive disorder, Post-traumatic stress disorder (PTSD), Acute stress disorder, Generalized Anxiety Disorder
which famous patient reinforces the notion that episodic and semantic memory are distinct in the brain? how?
Patient K.C. After motorbike accident, has severe amnesia, in which he can remember facts but not events in his life, and can't imagine the future
what are brain seizures
Prolonged synchronous discharge of large numbers of neurons, as seen repeatedly in epilepsy. may be general seizures (involve whole brain) or partial
which pathway is the major nociceptive pathway
Spino-parabrachial nociceptive pathway
VEP
Visual Evoked Potential, useful test for MS and optic neuritis. record potentials from occipital lobe *in response to a stimulus* eg chequerboard (like an EEG, but evoked potentials, not spontaneous).
which two structures mainly function to *focus* light onto the retina?
cornea and crystalline lens
the iris is sandwiched between which two layers
cornea and lens
conus medullaris
conical lower extremity of the spinal cord, near L1-2
pink eye is AKA
conjunctivitis
function of horizontal cells of retina
connect photoreceptors across the retina to pool them (so that in dark, you can use *groups* of photoreceptors to increase signal strength, at the cost of resolution)
what is the dorsal column/medial lemniscus system?
conscious ascending pathway; carries sensory info of fine touch (tactile sensation), vibration + proprioception. In the spinal cord, sensation travels via the dorsal columns (fasciculus cuteatus&gracilis). In the brainstem, it is transmitted through the medial lemniscus
explicit memory
conscious, intentional recollection information 'you know that you know' - eg as remembering the time of an appointment. AKA declarative memory
describe the descending vestibulospinal system
consists of *lateral vestibulospinal tract* (fast acting - helps us walk upright) and *medial vestibulospinal tract *(slower - affects head movements)
ocular tremor
constant microtremor of healthy eyes, necessary to prevent fading of stabilised images
describe the outer segment of photoreceptor cells?
contains a stack of membranous disks which contain light sensitive photopigments for absorption (cones have less disks than rods)
how is ventral striatum involved in depression and manic depression?
contains nucleus accumbens/reward system. decreased in major depression, increased in manic depression
function of precentral gyrus
contains primary motor cortex, highest level in brain for control of movement. mainly controls contralateral side
function of postcentral gyrus
contains primary somatosensory cortex; consciously perceives the modalities of touch, temp, pain and pressure from contralateral body
which factors affect pain processing within brain to give different pain experiences?
context of pain - beliefes, expectation, placebo. mood - depression, anxiety. cognitive set - hypervigilance, distraction, catastrophizing. chemical&structure - neurodegeneration, maladaptive plasticity
what causes phantom limbs
continued activity in the area of somatosensory cortex where the limb used to input
athetosis
continuous succession of slow, writhing, involuntary movements of the hands and feet. a result of basal ganglia disorder
which increases outflow of aqueous humour into the canal of schlemm, contraction or dilation of ciliary muscle?
contraction
do unilateral lesions of basal ganglia lead to ipsilateral or contralateral motor disorders?
contralateral
major function of corticospinal and corticobulbar tracts
control of fractionated (skilled voluntary) movements eg of the hands or vocal cords
which lense corrects presbyopia?
convex lense
'kera-' refers to what in the eye?
cornea
what is the first and most powerful lens of the optic system?
cornea
name the collagen fibrils surrounding each individual peripheral neuron
endoneurium
what might you look for in brain scan for huntingtons disease?
enlarged anterior horn of lateral ventricles, shrunken caudate/putamen
bouton
enlarged part of a nerve fiber or cell, especially an axon, where it forms a synapse with another nerve
name 4 viruses which cause meningitis
enteroviruses, mumps, Lymphocytic choriomeningitis virus, (HIV)
where does the perforant path originate?
entorhinal cortex, layer 2
hippocampus is associated with which form of memory?
episodic
network/systems memory consolidation
episodic memories are initially stored in hippocampus and slowly moved (consolidated) into neocortex
give 3 types of declarative memory
episodic memory (recollecting specific events in time), semantic memory (remember familiar objects/facts), and working memory (a short-term hold)
once consolidated, where are episodic memories stored in the cortex?
episodic memory consists of components light sight, sound, texture, context, stored in different areas of cortex.
reversal potential
equilibrium potential of an ion = the membrane potential at which there is no net flow of that particular ion from one side of the membrane to the other. calculated using nernst equation
what kind of chemical structure is ACh?
ester (not amino acid/derivative like most NTs)
which common recreational drug has many features in common with anaesthetics
ethanol
which drug is usually used in absence seizures
ethosuximide
which nerves can diabetes damage?
everyone goes on about the optic nerve... but diabetes can damage any nerve, leading to dysfunction/neuropathy
how does amyloid beta form?
is cleaved off from amyloid precursor protein (APP) by beta secretase and gamma secretase
name 5 structures of the ascending arousal system
locus coeruleus, laterodorsal tegmental nuclei, pedunculopontine tegmental nuclei, tuberomammillary nucleus, Raphe nuclei
what does LQTS stand for?
long QT syndrome
cingulate gyrus
long curved structure on the medial surface of cerebral hemispheres; the cortical part of the limbic system. wraps around corpus callosum + helps regulate emotion/pain/predicting + avoiding negative consequences
Meibomian gland
long sebaceous gland that lubricates the surface of eye. orifice can become blocked causing styes/chalazia
what is the reverse of long term potentiation
long term depression
corpus callosum lies deep within which fissure of the brain?
longitudinal
myenteric plexus sits deep to which muscles?
longitudinal muscles of the gut wall
metamorphopsia
looking at a straight line, patient sees a wavy line/kink. usually due to a defect in the retina
are commisural fibres between cerebral hemispheres white or grey matter?
white
are the peduncles made from grey or white matter?
white
do acending and descending spinal tracts run in white or grey matter?
white
is the corpus callosum white or grey matter?
white
corticobulbar tract
white matter pathway descending from the primary motor cortex, through the corona radiata of the internal capsule, to contra- and ipsi-lateral cranial nerve nuclei in the brainstem ('bulb' refers to the medulla).
nociceptors
widely branched bare nerve endings which respond to mechanical or inflammatory stimuli, sending pain signals to CNS and mediating the axon reflex
how can you treat korsakoff's amnesic state? how effective is this?
with vitamine B1 (thiamine). reduces confusion/motor symptoms, but amnesia usually persists
if sudanophilic lipids/myelin deposits are seen in a myelin plaque, how recent is the demyelination?
within last few days
in which layer do superficial skin receptors lie?
within the dermis, just below the epidermis
where is the lateral corticospinal tract found in spinal cord?
within the lateral region; lateral to propriospinal tract and medial to rubrospinal tract
are there more men or women in the UK with dementia?
women
which kind of memory is prefrontal cortex associated with?
working memory eg problem solving/delayed response task. (prefrontal neurons shown to fire during time delay between which box flashed with light and picking where food will be)
what are the axes of an audiogram
y axis = hearing level (decibels). x axis = tone frequency (Hz)
are opiods peptides?
yes
can caffeine induce drug dependence
yes