Mammalian Physiology Chp 13-19
What do red blood cells (erythrocytes) lack?
A nucleus
What is tubuloglomerular feedback?
A paracrine signaling mechanism through which changes in fluid through the loop of Henle influence the glomerular filtration rate (GFR) -When NaCl delivery past the macula dense increases as a result of increased glomerular filtration rate, the macula densa cells send a paracrine message to the neighboring afferent arteriole -The afferent arteriole then constricts, increasing resistance and decreasing the glomerular filtration rate
What is the stroma composed of?
Fibroblast-like reticular cells, collagenous fibers, and extracellular matrix
What is the equation for filtered load?
Filtered load = GFR x plasma concentration -Filtered load of inulin = excretion rate of inulin
What happens to flow when resistance increases?
Flow decreases
What happens to flow when resistance decreases?
Flow increases
What is filtration in the kidneys?
Fluid moving out of the blood and into the lumen of the nephron -Filtration only occurs in the renal corpuscle (glomerulus and Bowman's capsule)
What regulate pacemaker cells?
Funny ion channels which allow for leakage of calcium into the cell -The membrane potential rests at -60 mV and as calcium leaks into the cell potassium leaves the cell, the cell reaches a threshold potential which fires an action potential depolarizing the pacemaker cells which allows the heart to send an action potential into the heart
When do innate reflexes develop?
Innate (inborn) reflexes are genetically determined
What are intercalated disks?
Intercalated disks contain desmosomes that transfer force from cell to cell, and gap junctions that allow electrical signals to pass rapidly from cell to cell
What does tissue plasminogen activator (tPA) do?
It activates plasmin so that the clot can be broken up
What does the superior vena cava do?
It brings deoxygenated blood from the brain, head, and arms to the right atrium of the heart
What does the inferior vena cava do?
It brings deoxygenated blood from the trunk, liver, digestive tract, kidneys, pelvis, and legs to the right atrium of the heart
What does active factor XIII do?
It converts fibrin into a cross-linked polymer that stabilizes the clot
What does sympathetic innervation and epinephrine do to your veins?
It increases venous constriction
What is thrombopoietin (TPO)?
It is a cytokine (hormone) that stimulates megakaryocytic production. It is produced in the liver.
What is erythropoietin (EPO)?
It is a cytokine (hormone) that stimulates red blood cell (erythrocyte) production. It is produced in kidney cells.
What is darbepoetin?
It is a longer activating derivative of EPO that increases red blood cell production
What does the P wave look like?
It is a small wave that occurs right before the peak wave
What does ischemic mean?
Lack of oxygen
What is the primary site for creating dilute urine?
Loop of Henle because as filtrate passes through the loop, proportionately more solute is reabsorbed than water, and the filtrate becomes hyposomotic relative to the plasma -Its now about 100 mOsM
What prevents tetanus in myocardial contractile cells?
Long action potentials due to calcium entry in the cell
What do lymphoid progenitors make?
Lymphocyte stem cells
What are autonomic reflexes?
Reflexes controlled by the autonomic nervous system -Involuntary reflexes such as visceral reflexes
What are somatic reflexes?
Reflexes involving somatic motor neurons and skeletal muscle
What is the juxtaglomerular apparatus?
Region where the distal tubule of the nephron passes between afferent and efferent arterioles
What is the primary function of the kidneys?
Regulation of ECF volume and blood pressure
What does converting vitamin D3 do?
Renal enzymes help convert vitamin D3 into a hormone that regulate calcium balance
What does the internodal pathway do?
Routes the direction of electrical signals so the heart contracts from apex (bottom) to base (top)
What do some diabetics have in their urine?
Sugar gets excreted by their kidneys into their urine
How does active transport of sodium work?
The active reabsorption of sodium is the primary driving force for most renal reabsorption -Sodium enters the tubule lumen through various membrane proteins, moving down its electrochemical gradient -Sodium is then pumped out of of the basolateral side in exchange for potassium by the sodium potassium ATPase and sodium gets reabsorbed -Apical movement of sodium uses a variety of symport and antipode transport proteins or open leak channels -In the proximal tubule, the sodium hydrogen exchanger (NHE) plays a major role in sodium reabsorption, as does the apical epithelial sodium channel (ENaC)
What are granular cells?
The adjacent wall of the afferent arteriole has specialized smooth muscle cells called granular cells -Also known as juxtaglomerular cells or JG cells
What is stroke volume?
The amount of blood pumped by one ventricle during a contraction -The average stroke volume is 70 mL
What is mean corpuscular hemoglobin (MCH)?
The amount of hemoglobin per red blood cell (erythrocyte)
What is mean corpuscular hemoglobin concentration (MCHC)?
The amount of hemoglobin per volume of one red blood cell (erythrocyte)
What is mean corpuscular volume (MCV)?
The average volume of one red blood cell (erythrocyte) -A corpuscle is a small unattached cell
What does hydrostatic pressure (PH) of blood do for filtration?
The hydrostatic pressure of blood flowing through the glomerular capillaries forces fluid through the leaky endothelium -Capillary blood pressure averages 55 mm Hg and favors filtration into Bowman's capsule -Although pressure decreases as blood moves through the capillaries, it remains higher than the opposing pressures -Due to this, filtration takes place along nearly the entire length of the glomerular capillaries
What is mean red cell volume (MCV)?
The size of red blood cells -This can also provide clues to the presence of disease
What is a functional unit?
The smallest structure that can perform all the functions of an organ
What is hydraulics?
The way blood is moved through a system
What is the function of the renal portal system?
To filter fluid out of the blood and into the lumen of the nephron at the glomerular capillaries, then to reabsorb fluid from the tubule lumen back into the blood at the peritubular capillaries.
What is the hemoglobin value in a complete blood count?
The hemoglobin value reflects the oxygen carrying capacity of red blood cells (erythrocytes) -Normal Ranges: Male 14-17 Female 12-16
What is cardiac output?
The volume of blood pumped by one ventricle in a given period of time -The average cardiac output is 5 L/min
What is the glomerular filtration rate (GFR)?
The volume of fluid that filters into Bowman's capsule per unit of time -Average GFR is 125 mL/min or 180 L/day -This rate means that the kidneys filter the entire plasma volume 60 times a day or 2.5 times every hour
True/False: Glomerular filtration rate (GFR) is relatively constant over a wide range of blood pressures. As long as mean arterial blood pressure remains between 80 mmHg and 180 mmHg, GFR averages 180 L/day.
True
True/False: Increased resistance of efferent arteriole decreases renal blood flow but increases hydrostatic pressure and the glomerular filtration rate (GFR).
True
True/False: Most corticospinal pathways (about 90%) cross to the opposite side of the body at the pyramids found in the medulla oblongata.
True
True/False: On an electrocardiogram every 25mm is one second.
True
True/False: Reabsorption of water and solutes from the tubule lumen to the ECF depends on active transport.
True
True/False: Red blood cells get trapped in the fibrin mesh of a clot.
True
True/False: Reflex movement is the least complex movement and is integrated at the spinal cord or brain stem.
True
True/False: Sarcomere length affects force of contraction in cardiac muscle.
True
True/False: Secretion occurs in the proximal tubule, the distal tubule, and the collecting ducts of the nephrons of the kidneys.
True
True/False: Sensory neuron fires when muscle contracts and pulls collagen fiber of the tendon tight.
True
True/False: Skeletal muscle reflexes are controlled by different sensors such as proprioceptors.
True
True/False: Some smooth muscles, such as the digestive system and cardiac, have their own action potentials. Those action potentials can control how that organ will respond.
True
True/False: Spinal reflexes do not require input from the brain.
True
True/False: Summation does not occur in cardiac muscle because the refractory period is so long and there is no time to sum action potentials.
True
True/False: The adrenal cortex contains all Bowman's capsules, proximal and distal tubules.
True
True/False: The adrenal gland is important for the production of catecholamines.
True
True/False: The adrenal medulla contains loops of Henle and collecting ducts.
True
True/False: The distance furthest from the where the fluid is flowing out has the highest pressure.
True
True/False: The heart is a pump
True
True/False: The kidneys make up about 4% of our body weight but they can handle about 20-25% of our cardiac output at any one time.
True
True/False: The morphology (shape) of red blood cells (erythrocytes) can provide clues to the presence of disease.
True
True/False: The proximity of the ascending limb and the arterioles allows paracrine communication between the two structures.
True
True/False: The renal blood vessels, nerves, lymphatics, and ureters all emerge from the renal hilum (the concave surface of each kidney which faces the spine).
True
True/False: Vasoconstriction of the afferent arteriole increases resistance and decreases renal blood flow, capillary blood pressure or hydrostatic pressure, and the glomerular filtration rate.
True
True/False: Voluntary movement is the most complex movement and is integrated in the cerebral cortex.
True
True/False: When you excite muscles you always get a contraction.
True
True/False: You can take the bone marrow from mice and bone marrow from humans and mix it with colony stimulating factors (CSF) and induce the formation of all the cells in blood.
True
True/False: You get the first heart sound (lub) during ventricular systole and the second heart sound (dub) during ventricular diastole.
True
True/False: The autonomic system can control whether you have a fast or slow heart rate.
True -Parasympathetic neuron (acetylcholine on muscarinic receptor) leads to slow heart rate -Sympathetic neuron (norepinephrine on beta 1 adrenergic receptor) leads to fast heart rate
What is prolapse?
When the atrioventricular valves whoosh back into the atria causing blood to leak back into the atria
What happens to blood pressure when blood vessels constrict?
Blood pressure increases
What are the three filtration barriers that a substance leaving the plasma must pass through?
-The glomerular capillary endothelium -A basal lamina -The epithelium of the Bowman's capsule
What does the atrioventricular node do?
- Receive signal from the SA node through internodal pathway - Forces signal to pause before sending it on so that the atria can finish contracting -Atrioventricular node delay is accomplished by slower conduction signals through nodal cells -Sets the pace of the heartbeat at 50 bpm
If 120 mL of plasma filter each minute and the filtration is 20% what is the daily renal plasma flow?
864 L per day -Multiply the amount of mL by the minutes in a day -Multiply the percentage by the above value
How does blood flow through the renal portal system?
-Blood flows from the renal arteries into an afferent arteriole -From there it goes into the first capillary bed, the glomerulus -From there blood flows into the efferent arteriole and into the second set of capillaries, the peritubular capillaries which surround the tubule -Peritubular capillaries converge to form venues and small veins, sending blood out of the kidneys through the renal veins and towards the inferior vena cava
Step-by-step blood flow process:
-Both Vena Cavas -Right atrium -Tricuspid Valve (AV) -Right ventricles -Pulmonary semilunar valve -Right and left pulmonary arteries -Lungs -Left pulmonary veins -Left atrium -Bicuspid (mitral) valve -Left ventricle -Aortic valve -Aorta
What are the three pressures that influence glomerular filtration?
-Capillary blood pressure -Capillary colloid osmotic pressure -Capsule fluid pressure
What does alpha-gamma coactivation look like?
-A load is added to a muscle -The muscle and muscle spindles stretch as the arm extends causing muscle spindle afferents to fire more frequently -Increased afferent signals to spinal cord -Increased efferent output through alpha motor neurons -Muscle contratcs -Firing rate of afferent sensory neuron decreases -Reflex contraction initiated by muscle stretch restores arm position and prevents damage from over-stretching -This whole process is an example of a negative feedback loop
How does electrochemical coupling drive the signal in a cardiac muscle beat?
-Action potential comes down the heart muscle fiber and enters from adjacent cell -Voltage-gated calcium channels (L-type) open and calcium enters the cell (extracellular calcium contributes 10%) -Calcium induces calcium release through ryanodine receptor channels (RyR) in the sarcoplasmic reticulum -Local release causes calcium to spark (depolarization) -Summed calcium sparks create a calcium signal -Calcium ions bind to troponin to initiate contraction -Relaxation occurs when calcium unbinds from troponin -Calcium is pumped out of the cytoplasm and back into the sarcoplasmic reticulum for storage -Calcium is exchanged with sodium out of the heart by the NCX antiporter (calcium leaves and sodium comes in) -Sodium gradient is maintained by the sodium-potassium ATPase
What are the different proteins found in blood plasma?
-Albumins: there are multiple types of these -Globulins: there are multiple types of these -Fibrinogen -Transferrin
What are the organic molecules in blood plasma?
-Amino acids -Proteins -Glucose -Lipids -Nitrogenous waste
What are the two layers that kidney is arranged in?
-An outer cortex -Inner medulla -These layers are formed by the organized arrangement of microscopic tubules called nephrons
What are some vasoconstrictors/ platelet activating factors?
-Angiotensin II -Thromboxane A2 -Serotonin
What hormones affect arteriolar resistance?
-Angiotensin II: potent vasoconstrictor -Prostaglandins: vasodilators -Renin: vasoconstriction -These can affect the filtration coefficient by acting on podocytes or mesangial cells -Podocytes change the size of the glomerular filtration slits. If the slits widen, more surface area is available for filtration, and the glomerular filtration rate (GFR) increases -Contraction of mesangial cells changes the glomerular capillary surface area available for filtration
What are some of the foreign substances (xenobiotics) that kidneys excrete?
-Artificial sweetener saccharin -The anion benzoate -Part of the preservative potassium benzoate (diet soft drinks) -Penicillin
How do hormones and the autonomic nervous system alter the glomerular filtration rate (GFR)?
-Changing the resistance in the arterioles -Altering the filtration coefficient -Sympathetic innervation of alpha receptors on vascular smooth muscle causes vasoconstriction -If systemic blood pressure drops sharply, like during a hemorrhage or severe dehydration, sympathetically induced vasoconstriction of the arterioles decreases the glomerular filtration rate (GFR) and renal blood flow
What happens when you have atrial fibrillation?
-Common condition -Electricsl signals that are in the sinoatrial node cause the heart to keep trying to beat (fibrillation) when its not supposed to which can lead to blood clots in the heart and brain or a pulmonary embolism
What are some of the metabolic wastes that the kidneys excrete?
-Creatine from muscle metabolism -Nitrogenous wastes urea and uric acid -A metabolite of hemoglobin called urobilinogen (yellow color of urine) -Hormones
How does organic anion secretion work?
-Direct active transport: the sodium potassium ATPase keeps intracellular sodium low -Secondary indirect active transport: the sodium dicarboxylate cotransporter (NaDC) concentrates a dicarboxylate inside the cell using energy stored in the sodium gradient -Tertiary indirect active transport: the basolateral organic anion transporter (OAT) concentrates organic anions (OA-) inside the cell, using the energy stores in the dicarboxylate gradient -Organic anions enter the lumen by facilitated diffusion
How do catecholamines increase cardiac contraction (contractility)?
-Epinephrine and norepinephrine bind to beta 1 adrenergic receptors which activate cAMP through a G alpha S second messenger system resulting in phosphorylation of voltage gated calcium channel. This increases the time that they stay open which increases the amount of calcium that enters from the ECF. -Another way is for phosphorylation to occur on phospholamban which leads to an increase in calcium ATPase on the sarcoplasmic reticulum which increases the stores of calcium and more calcium gets released
What are the three main cellular elements of blood?
-Erythrocytes: red blood cells -Platelets: these split off from megakaryocytes -Leukocytes: white blood cells
How does platelet plug formation occur?
-Exposed collagen binds and activates platelets -The exposed collagen mediates adhesion of the alpha v beta 3 integrins on the platelets and activation -Platelet factors get released (platelet activating factor) -These factors attract more platelets -Platelets aggregate into platelet plug
What are some options for dissolving blood clots?
-Fibrinolytic drugs such as streptokinase (from bacteria) and tissue plasminogen activator (tPA) -These combined with anti platelet agents further prevent plug and clot formation -Aspirin (acetylsalicylic acid) prevents platelet plug formation by inhibiting COX enzymes because they promote the synthesis of the platelet activator thromboxane A2 -Warfarin (Coumadin) is an anticoagulant that blocks the action of vitamin K, a coactivator in the synthesis of clotting factors II (thrombin), VII, IX, and X -EGTA is an anticoagulant that removes free calcium from the plasma (calcium is an essential clotting factor)
How does endocytosis reabsorption work?
-Filtered proteins are too large to be reabsorbed by carriers or through channels -Most enter proximal tubule cells by receptor-mediated endocytosis -Once in the cells, the proteins are digested in lysosomes -The resulting amino acids are transported across the basolateral membrane and absorbed into the blood -The renal digestion of small filtered proteins is actually a significant method by which peptide signal molecules can be removed from the circulation
What is glomerular capillary endothelium?
-Glomerular capillaries are fenestrated capillaries with large pores that allow most components of the plasma to filter through the endothelium -The pores are small enough to prevent blood cells from leaving the capillary -The negatively charged proteins on the pore surfaces help to repel negatively charged plasma proteins
How does tubuloglomerular feedback help GFR autoregulation?
-Glomerular filtration rate (GFR) increases -Flow through proximal tubule increases -Flow past macula densa increases -Paracrine signaling (release of renin) from macula densa is sent to afferent arteriole -Afferent arteriole constricts -Resistance in afferent arteriole increases -Hydrostatic pressure in glomerulus decreases -GFR decreases
What are some endogenous anticoagulants?
-Heparin: block active factors IX, X, XI, and XII -Antithrombin III: block active factors IX, X, XI, and XII -Protein C: inhibits clotting factors V and VIII
What happens when you have ventricular fibrillation?
-Immediately life threatening -When the ventricles fibrillate instead of pumping blood (instead of contracting they quiver) you don't get pumping of the blood to the brain which leads to not enough oxygen to the brain and you die
What two mechanisms limit extent of clotting?
-Inhibition of platelet adhesion -Inhibition of the coagulation cascade and fibrin production
What are the two pathways that initiate coagulation?
-Intrinsic pathway known as contact activation: relies on cells contacting collagen and then other factors being released -Extrinsic pathway known as cell injury pathway: when damaged tissues expose tissue factor (tissue thromboplastin or factor III) the damage exposes the tissue factor itself which can then initiate the coagulation cascade through factor 7 -Eventually both of these pathways meet at the common pathway
How does iron end up inside of heme?
-Iron (Fe) is ingested from the diet -Iron is absorbed by active transport in a section of small intestine -Transferrin protein transports iron in plasma and then to the bone marrow -Bone marrow uses iron to make hemoglobin (Hb) as part of red blood cell (erythrocyte) synthesis -The red blood cells will live about 120 days -The spleen destroys old red blood cells and converts hemoglobin to bilirubin -Bilirubin and metabolites are excreted in urine and feces through the kidneys -The liver also can metabolize bilirubin and excrete it in bile through feces -Excess iron gets stored in the liver as ferritin
What affects stroke volume (force of contraction)?
-Length of muscle fiber which is determined by the volume of blood at the beginning of a contraction -Contractility (force) of the heart -As stretch of the ventricular wall increases, so does stroke volume -Preload: the degree of myocardial stretch before the contraction
What are the different types of white blood cells (leukocytes)?
-Lymphocytes: also called immunocytes; can either be T or B cells -Monocytes: these develop into macrophages if they go into the tissue; they are also called phagocytes -Neutrophils (polymorphonuclear leukocytes): known as phagocytes and granulocytes -Eosinophils: these react during a normal immune response or an allergic immune response; also called granulocytes -Basophils: also called granulocytes; tissue basophils are called mast cells
What are some way that the glomerular filtration rate (GFR) is regulated outside of pressure?
-Myogenic response -Tubuloglomerular feedback -Hormones and autonomic neurons
REMEMBER!!!!! Flow is dependent on the pressure gradient, not on the total pressure of the system.
-One tube has a total pressure of 175mmHg and a pressure gradient of 25mmHg -The other tube has a total pressure of 55mmHg and a pressure gradient of 25mmHg -THEY BOTH HAVE THE SAME FLUID FLOW
How does phosphorylation of phospolamban shorten contraction duration?
-Phosphorylation of phospholamban leads to an increase in the amount of calcium ATPase on the sarcoplasmic reticulum. This leads to calcium being removed from the cytosol faster which shortens the calcium troponin binding time
How does pressure change work?
-Pressure created by contracting muscles is transferred to blood -Driving pressure is created by the left and right ventricles of the heart -Volume changes affect blood pressure in cardiovascular system
KNOW FIGURE 13.10 THE CORTICOSPINAL TRACT
-Primary motor cortex -Midbrain -Motor nuclei of cranial nerves -Medulla oblongata where they cross -Lateral corticospinal tract and anterior corticospinal tract -Somatic motor neurons to skeletal muscle or goes straight to spinal cord
What are monosynaptic reflexes?
-Reflexes that contain only two neurons; they have a single synapse between the afferent and efferent neurons (one afferent and one efferent) -Only somatic motor reflexes can be monosynaptic
What are polysynaptic reflexes?
-Reflexes that include one or more interneurons between the afferent and efferent neurons -All autonomic reflexes are polysynaptic because they have 3 neurons (one afferent and two efferent) -Both synapses are in the CNS
What are the functions of the kidneys?
-Regulation of the extracellular fluid volume and blood pressure: when ECF volume decreases, blood pressure also decreases -Regulation of osmolarity: tries to maintain blood osmolarity close to 290 mOsM -Maintenance of ion balance: balances dietary intake with urinary loss. Sodium is the major ions involved in regulation of ECF volume and osmolarity, potassium and calcium are close seconds -Homeostatic regulation of pH: the kidneys don't work as fast as the lungs do but if the ECF is too acidic they remove hydrogen ions and conserve bicarbonate ions (buffer) if its too basic they remove bicarbonate and conserve hydrogen ions -Excretion of wastes: remove metabolic wastes and xenobiotics (drugs and environmental toxins) -Production of hormones: they synthesize erythropoetin, release renin, convert vitamin D3
What are the three groups of myocardial autorhythmic cells?
-Sinoatrial (SA) node -Atrioventricular (AV) node -Purkinje fibers
How does the conducting system of the heart work?
-Sinoatrial node (located in the right atrium) depolarizes -Electrical activity goes rapidly to the atrioventricular node (located at the bottom of the right atrium) via internodal pathways -Depolarization spreads more slowly across atria and conduction slows through the atrioventricular node -Depolarization moves rapidly through ventricular conducting system (Bundle of His) to the apex of the heart (branches at the purkinje fibers) -Depolarization wave spreads upwards from the apex due to the purkinje fibers which branch off to the sides of the heart
What do autonomic neurons control?
-Smooth muscle -Cardiac muscle -Glands -Adipose tissue
How does secondary active transport work?
-Sodium moving down its electrochemical gradient uses the SGLT protein to pull glucose into the cell against its concentration gradient -Glucose diffuses out the basolateral side using the GLUT protein -Sodium is pumped out by sodium potassium ATPase -This is an example of symport -This mechanism is used to reabsorb glucose, amino acids, lactate, citric acid cycle intermediates such as citrate and alpha ketoglutarate, and ions such as phosphate and sulfate
Which reflexes are classified as neural reflexes?
-Somatic and automatic reflexes -Spinal reflexes if integrated in the spinal cord -Cranial reflexes if integrated in the brain -Innate reflexes (patellar tendon) -Monosynaptic and polysynaptic reflexes
How do red blood cells (erythrocyte) mature?
-Stem cell in bone marrow -Enucleated stem cell forms -Reticulocyte forms -Reticulocyte expels nucleus -Red blood cell enters venous sinus -Mature red blood cells squeeze through the endothelium to reach the circulation
How do neutrophils mature in bone marrow?
-Stem cell in bone marrow -Neutrophils go through many stages with different shapes until a mature neutrophil enters the venous sinus -Mature neutrophils squeeze through the endothelium to reach the circulation
Another explanation of alpha-gamma coactivation
-The alpha motor neuron fires causing gamma motor neurons to fire -Muscle and intrafusal fibers both contract -The muscle shortens but the stretch on the intrafusal fibers does not slacken so the firing rate of the afferent neuron remains constant
What is the common pathway for coagulation?
-The intrinsic and extrinsic pathways come together to make thrombin -Thrombin converts fibrinogen into soluble fibrin polymers -Fibrin fibers form part of the clot -The blood clot can't remain there forever so to remove it you have to break fibrin down by the enzyme plasmin (fibrinolysis) and repair the tissue
What is the structure of a nephron?
-The nephron begins with a hollow, ball-like structure called the Bowman's capsule which surrounds the glomerulus -From there, filtered fluid flows into the proximal tubule -Next it goes into the loop of Henle -From there, it goes into the distal tubule and finally into the collecting ducts -These are all structures of a nephron
What influences the glomerular filtration rate (GFR)?
-The net filtration pressure: which is determined by the three pressures that influence filtration -The filtration coefficient -It is controlled primarily by regulation of blood flow through the renal arterioles
What are the two components of the filtration coefficient?
-The surface area of the glomerular capillaries available for filtration -The permeability of interface between the capillary and Bowman's capsule
What do the Purkinje fibers do?
-The third and final pacemaker of the heart -Transmits electrical signals down the atrioventricular bundle (bundle of His) to left and right bundle branches -Distributes electrical impulses through the ventricles -Sets the pace of the heartbeat at 25-40 bpm
What do proprioceptors do?
-They monitor and maintain body position -Input signals from proprioceptors go to the CNS through sensory neurons -The CNS then integrates the input signal -Somatic motor neurons, activated by alpha motor neurons, then carry the output signal -The effectors are contractile skeletal muscle fibers, or extrafusal muscle fibers
What stops the positive feedback loop of the coagulation cascade?
-When all the collagen on the site has been used up so no more platelets can bind to it -Some of the lipids in the membrane turn into different eicosanoids called prostacyclin which blocks the adhesion of platelets and aggregation (prevents the blood clot from getting too big) -Nitric oxide release which slows down the release of platelet aggregation
How does micturition occur?
-When the bladder is full the stretch receptors fire -Parasympathetic neurons fire and motor neurons stop firing -Smooth muscle contracts and the internal sphincter is passively pulled open while the external sphincter relaxes
When thinking about performing a voluntary movement what is the pathway through the brain that it takes? FIGURE 13.8
-You have an idea -That idea goes to the cortical association areas of the brain -That idea then goes to the basal ganglia -Finally the idea goes to the motor cortex which allows the movement to occur
How many nephrons are in one kidney?
1 million per kidney
What is the net driving force of filtration?
10 mmHg in the direction favoring filtration -This is not very high but when combined with the leaky nature of the fenestrated glomerular capillaries, it results in rapid fluid filtration into the tubules -The net filtration pressure is composed of the hydrostatic pressure (+), the colloid osmotic pressure (-), and the Bowman's capsule fluid pressure (-)
How many leads does the modern electrocardiogram have?
12 lead: -6 on the trunk used to be just a 3 lead
What is the normal hemoglobin range for males?
14-17 g/dL whole blood
What concentration of sodium would you expect to find in blood plasma?
140 mM because it is similar to the sodium content in the ECF
What does the urinary system consist of?
2 kidneys, 2 ureters, urinary bladder, urethra
How many different types of tissues are present in the heart?
3 -Myocardium -Pericardium
How many kinds of blood vessels are there?
3 -Veins: return blood to the heart -Arteries: take blood away from the heart -Capillaries: allow for exchange of microscopic materials such as gases
How many waves are there in an electrocardiogram?
3: -P waves: represent depolarization of the atria -QRS complex: represents waves of ventricular depolarization and atrial repolarization -T waves: represent repolarization of the ventricles
How many types of proprioceptors are there?
3: -Joint receptors: found in capsules and ligaments around joints -Golgi tendon organ: found in skeletal muscles (help link the muscle to the tendon) -Muscle spindle: found in skeletal muscle
When blood doping, would you expect hematocrit values to be higher or lower than normal?
A higher hematocrit because hematocrit is the percentage of a blood sample volume that is packed red blood cells. Red blood cells are the oxygen carrying components of blood.
What is the red cell count?
A machine counts erythrocytes as they stream through a beam of light -Normal Ranges: Male 4.5-6.5 x 10^3 Female 3.9-5.6 x 10^3
What does elevated levels of leukocytes (specifically neutrophils and monocytes) mean?
A bacterial infection
What is a thrombus?
A blood clot that adheres to an undamaged blood vessel wall and forms a blockage -Usually requires drugs to fix such as warfarin
What is hemophilia?
A coagulation disorder in which one of the factors in the coagulation cascade is either defective or lacking -Hemophilia A is the most common form and is characterized by deficiency of factor VIII -Hemophilia B is characterized by a deficiency in factor IX
What is a myotatic unit?
A collection of pathways controlling a single joint Ex: Monosynaptic stretch reflex or patellar tendon reflex
What is tetanus?
A continuous contraction of a muscle due to a rapid number of action potentials
What is erythropoietin (EPO)?
A cytokine/hormone that regulates red blood cell production
What is anemia?
A decrease in the oxygen-carrying ability of the blood (red blood cells, erythrocytes)
What is recombinant human EPO (rhEPO)?
A drug that increases red blood cell production
What is the loop of Henle?
A hairpin-shaped segment of the nephron that dips down towards the medulla and then back up -It is divided into two limbs: a thin descending limb and an ascending limb with thin and thick segments
What does the kidney tubule consist of?
A single layer of epithelia cells connected together near their apical surface -The apical surfaces are folded into microvilli (area-increasing folds) -The cell to cell junctions are mostly tight but some have selective permeability for ions
A small change in what has a large effect on resistance to blood flow?
A small change in the radius of the blood vessel -Vasoconstriction decreases blood flow -Vasodilation increases blood flow
Where is the apex of the heart?
A the bottom of the heart near the ventricles and diaphragm
What is a total white count?
A total white count includes all types of leukocytes but does not distinguish between them -Normal Ranges: Male and Female 4-11 x 10^3
What are juxtamedullary nephrons?
About 20% of the nephrons in a kidney dip down into the adrenal medulla
What are cortical nephrons?
About 80% of the nephrons in a kidney are in the outer cortex
What is on the inside of a red blood cell (erythrocyte)?
Actin attached to attachment proteins which help to keep the biconcave disk cytoskeleton shape of red blood cells
Where do action potentials in the heart start?
Action potentials start with the heart pacemaker cells
How do you treat Parkinson's disease?
Add L-DOPA to corpus striatum -Use drugs that enhance dopamine activity (add L-Dopa to corpus striatum), transplant dopamine secreting neurons, use dopamine receptor agonists, or prevent dopamine breakdown in the synaptic cleft by using a monoamineoxidase inhibitor -Dopamine does not cross the blood brain barrier
What does the left atria do?
After the blood has returned from the pulmonary valve and is now oxygenated it leaves the left atria and goes into the left ventricle where it exits the heart through the aorta
What is alpha-gamma coactivation?
Alpha-gamma coactivation is the simultaneous firing of alpha and gamma motor neurons to a muscle so that the extrafusal and intrafusal muscle fibers contract simultaneously.
What does A1C measure?
Amount of glycosylated hemoglobin as a percentage of total hemoglobin
What is used to asses heart fitness?
An electrocardiogram (ECG)
What is renin?
An enzyme that regulates the production of hormones involved in sodium balance and blood pressure homeostasis
What does the presence of microcytes indicate?
An iron deficiency
What is an inotropic agent?
Any chemical that affects contractility -Epinephrine, norepinephrine, and digitalis have positive inotropic effects (increases force of contraction by inhibiting sodium transport which slows the calcium removal from the cytosol ) -Digitalis is often used for heart failure -Chemicals with negative inotropic effects decreases contractility
What happens during isovolumic ventricular relaxation?
As ventricles relax, pressure in ventricles falls. Blood flows back into cusps of semilunar valves and snaps them closed
What happens during ventricular ejection?
As ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected
How do the intrinsic and extrinsic pathways work?
At each step, an enzyme converts an inactive precursor into an active enzyme, often with the help of calcium, membrane phospholipids, or additional factors.
What happens during atrial systole?
Atrial contraction forces small amount of additional blood in the ventricles
What does bone marrow consist of?
Bone marrow consists of blood cells in different stages of development and supporting tissue known as storm (mattress)
Where are blood cells produced?
Blood cells are made in bone marrow: -Red bone marrow produces red blood cells -Yellow bone marrow produces white blood cells
What happens to blood pressure when blood vessels dilate (widen)?
Blood pressure decreases
What happens to blood pressure when you reduce the volume of blood?
Blood pressure decreases
What happens during late diastole?
Both sets of chambers are relaxed and ventricles passively fill with blood
How do you calculate the ejection fraction?
By dividing the stroke volume by the end diastolic volume Stroke volume / EDV = Ejection fraction
How can you reduce hematocrit without removing red blood cells?
By drinking fluids because this will increase the plasma volume
Which ion extends the depolarized state of the cardiac contractile cells?
Calcium
What causes a plateau in the action potential in the cardiac contractile cells which allows for the heart to beat?
Calcium influx
What causes filtration in the kidneys?
Capillary pressure
Cardiac Muscle vs. Skeletal Muscle
Cardiac Muscle is: -Smaller and has a single nucleus per fiber -Branch and join neighboring cells through intercalated disks -Desmosomes allow force to be transferred -Gap junctions provide electrical connection -T-Tubules are larger and branch -Sarcoplasmic reticulum is smaller -Mitochondria occupy one-third of cell volume
What does the hepatic vein do?
Carries deoxygenated blood back to the heart
What does the hepatic portal vein do?
Carries nutrient-rich blood from the capillaries of the villi to the liver, then to the heart
What does the hepatic artery do?
Carries oxygenated blood to the liver
What do the renal veins do?
Carry blood from the kidneys to the inferior vena cava
What do renal veins do?
Carry deoxygenated blood back to the heart
What do the renal arteries do?
Carry oxygenated blood to the kidneys
What do the descending arteries do?
Carry oxygenated blood to the pelvis and legs
What can regulate leukopoiesis?
Colony stimulating factors (CSF) -White blood cells (leukocytes) can also regulate their own generation; they can induce the formation of other white blood cells
What happens if resistance decreases in the efferent arteriole and hydrostatic pressure in the glomerular capillaries decreases?
Decreased glomerular pressure decreases the glomerular filtration rate (GFR)
What is hypoxia?
Deficiency in the amount of oxygen reaching the tissues which induces the expression of erythropoietin (EPO) which will generate more red blood cells (erythrocytes)
What is aplastic anemia?
Destruction or inhibition of red bone marrow and red blood cells (erythrocytes) caused by certain drugs or radiation
What does an electrocardiogram do?
Detects positive or negative electricity on the surface of the skin which is part of the electrical signals in the body -Can tell whether the heart is beating too fast or too slow -Can tell if the heart rhythm is normal; can check for irregular beats -Can tell if all of the normal waves are present (P, QRS, and T)
What does the septum do?
Divides the heart into right and left sides
What causes long QRS syndrome?
Drugs administered in the clinic such as seldane or zeldane (couldn't understand her) -These drugs delay heart repolarization
When are the semilunar valves open?
During ventricular contraction and while the atrioventricular valves are closed
What is diabetic nephropathy?
End stage renal failure in which kidney function has deteriorated beyond recovery -Occurs in about 30-40% of type 1 diabetics and 10-20% of type 2 -Usually begins with an increase in glomerular filtration followed by the appearance of proteins in the urine (proteinuria) -Which is an indication that normal filtration barrier has been altered -In later stages, filtration rates decline (the protein involved in maintaining colloid osmotic pressure is having problems) -The glomerular basal lamina thickens and changes in podocytes and mesangial cells occur -Abnormal growth of mesangial cells compresses the glomerular capillaries and impedes blood flow which contributes to the decrease in glomerular filtration -At this point the patient must have their kidney functions supplemented by dialysis, and may eventually need a kidney transplant
What makes colony stimulating factors (CSF)?
Endothelial cells
What causes myocardial contractile cells to depolarize?
Entry of sodium
What is glucosuria or glycosuria?
Excretion of glucose in the urine -Usually indicates an elevated blood glucose concentration
What is the formula for excretion?
Excretion= filtration - reabsorption + secretion
What causes myocardial contractile cells to repolarize?
Exit of potassium
What is the equation for flow when dealing with resistance?
F=1/R
What factor gets activated at the common pathway?
Factor X gets activated at the common pathway and it leads to the formation of prothrombin into thrombin -Thrombin cleaves fibrinogen into fibrin
What does sympathetic activity do to the heart rate?
GPCRs such as beta 1 adrenergic receptors on autorhythmic cells speed up heart rate
What innervates intrafusal fibers?
Gamma motor neurons from the CNS innervate intrafusal fibers and cause contraction of intrafusal fibers
What is the renal corpuscle?
Glomerulus and bowman's capsule
How do you measure cardiac output?
Heart rate x stroke volume = cardiac output
KNOW TABLE 16.2 CYTOKINES INVOLVED IN HEMATOPOIESIS
Hematopoietic Cytokines
One hallmark of illegal EPO use is elevated reticulocytes in the blood. Why would this suggest greater-than-normal EPO activity?
If red blood cell development becomes more rapid, more reticulocytes (the final immature stage of red blood cell development) may be released into the blood before they have time to mature
What are the vasa recta?
In juxtamedullary nephrons, the long pertiubular capillaries that dip into the medulla are called vasa recta
Where are cranial reflexes integrated?
In the brain
Where is dietary iron absorbed?
In the small intestine and it uses the transport protein transferrin in the blood to get into the red bone marrow -Hemoglobin components are then recycled and excess iron binds to ferritin in liver -Some iron from heme groups are reused in new heme groups
What happens if resistance increases in the efferent arteriole, blood dams up in front of the constriction, and hydrostatic pressure in the glomerular capillaries increases?
Increased glomerular pressure increases the glomerular filtration rate (GFR)
What does blood doping do?
Increases the oxygen carrying capacity of the blood
What is inulin?
It is a substance that gets filtered and 100% of it gets excreted; none of it gets reabsorbed or secreted
What does the basal lamina of the kidneys do?
It is an acellular layer of extracellular matrix that separates the capillary endothelium from the epithelium of the Bowman's capsule -It consists of negatively charged glycoproteins, collagen, and other proteins -It acts like a coarse sieve, excluding most plasma proteins from the fluid that filters through it
What is a hemoglobin molecule composed of?
It is composed of four protein globing chains, each centered around a heme group. In most adult hemoglobin, there are two alpha chains and two beta chains -Inside each alpha and bets chain is a heme group which consists of a porphyrin ring with an iron atom in the center
What does the T wave look like?
It is small wave that occurs after the peak wave
What does the platelet count do?
It is suggestive of the blood's ability to coagulate
What does the QRS complex look like?
It is the peak wave
What is secretion?
It is the transfer of molecules from the ECF into the lumen of the nephron -Depends mostly on membrane transport systems -The secretion of potassium and hydrogen by the distal nephron is important in the homeostatic regulation of those ions -Secretion enable the nephron to enhance excretion of a substance; If a substance is filtered into the tubule, not reabsorbed, and then more of it is excreted into the tubule from the pertitubular capillaries, excretion is very efficient -Secretion is an active process because it requires moving substrates against their concentration gradients -Secretion is a competitive process : probenecid competes with penicillin for the OAT transporter in the kidneys to prevent penicillin excretion in the urine
What does fibrinogen do?
It originates in the liver and forms fibrin threads that attach to platelets and form a tight plug for the clot (essential for blood clotting)
What does transferrin do?
It originates in the liver and other tissues. It acts as an iron transport.
What does the right atria do?
It receives blood returning to the heart from the body and sends it down into the right ventricle which sends the blood into the pulmonary valves to get oxygenated
What is the PR segment?
It represents conduction through the atrioventricular node and the atrioventricular bundle (Bundle of His)
What does voluntary movement require coordination between?
It requires coordination between the cerebral cortex, cerebellum, and basal ganglia.
What does parasympathetic activity to to heart rate?
It slows heart rate
How does voluntary movement travel?
It travels from the cortex to the spinal cord through the corticospinal tract
What do portal system do?
Join two capillary beds in series Ex: Hypothalamic Pituitary portal system (joins your hypothalamus and your pituitary)
What does hemostasis do?
Keeps blood inside damaged blood vessel by vasoconstriction, platelet plug, or coagulation
When do learned reflexes develop?
Learned (conditioned) reflexes are acquired through experience
What is auscultation?
Listening to the heart through the chest wall with a stethoscope
What type of cell makes platelets?
Megakaryocytes -These are giant cells with multiple copies of DNA in the nucleus -They have a lot of endoplasmic reticulum because they are constantly shedding off little pieces (platelets) -The edges of the megakayocyte break off to form cell fragments called platelets
What disease is most common with a diet low in iron?
Microcytic anemia
What is the pathway for the patellar tendon (knee jerk) reflex? Figure 13.5
Monosynaptic Event -Stimulus: tap to tendon stretches muscle -Receptor: Muscle spindle stretches and fires -Afferent Path: action potential travels through sensory neuron -Integrating Center: sensory neuron synapses in spinal cord on efferent path 1 and efferent path 2 -Efferent Path 1: somatic motor neuron -Efferent Path 2: interneuron inhibiting somatic motor neuron -Effector 1: quadriceps muscle -Effector 2: hamstring muscle -Response 1: quadriceps contracts, swinging lower leg forward -Response 2: hamstring stays relaxed, allowing extension of leg (reciprocal inhibition)
Where does most reabsorption in the kidneys occur?
Most reabsorption takes place in the proximal tubule, with a smaller amount of reabsorption in the distal segments of the nephrons
What is Parkinson's disease?
Movement disorder caused by the death of neurons that generate dopamine in the basal ganglia and substantial nigra. Characterized by resting tremor, slowed movement, rigidity of facial muscles, and shuffling gait, and reduction in capacity for language
What are muscle spindles and what do they do?
Muscle spindles are found buried among the extrafusal fibers of the muscle and they send information about muscle stretch to the CNS
What is the heart mostly composed of?
Myocardium (muscle)
What does the central region of the muscle lack?
Myofibrils
How does sympathetic stimulation and epinephrine increase heart rate?
Norepinephrine binds to beta 1 adrenergic receptors which causes an increase in potassium and calcium influx into the cell. This causes an increase in the rate of depolarization and the heart rate increases.
What depolarizes autorhythmic cells?
Open calcium channels
What is the pressure gradient equation?
P1-P2=P gradient If P gradient=0 then there is no fluid flow
What muscles hold open the tricuspid and bicuspid valves?
Papillary muscles
What is blood composed of?
Plasma and the three cellular elements
What is blood plasma composed of?
Plasma is the ground media in blood -92% water -7% proteins -1% gases (CO2 and O2) -Salts -Organic molecules -Trace elements and vitamins -Ions (sodium chloride and potassium)
What is a coagulation cascade?
Platelets stick to collagen in damaged vessels -Release of platelet-activating factor (PAF) > thromboxane A2
What is the crossed extensor reflex pathway? Also an example of a withdrawal reflex (Figure 13.6)
Polysynaptic Event -Painful stimulus activates nociceptor through the dorsal root ganglia (stepping on needle) -Primary sensory neuron enters spinal cord and diverges -One collateral on the sensory neuron activates ascending pathways for sensation (pain) and postural adjustment (shift in center of gravity) -The remaining collaterals on the sensory neuron activate alpha motor neurons -The extensor muscle in the quadriceps that was stepping on the needle gets inhibited by inhibitory neurons -The flexor hamstring on that same leg relaxes, moving foot away from painful stimulus -The extensor on the opposite leg contracts as the weight shifts to that leg -The flexor hamstring of that leg is inhibited by inhibitory neurons
What do the semilunar valves do?
Prevent blood that has entered the arteries from flowing back into the ventricles during ventricular relaxation
What does hemostasis do?
Prevents blood loss form a broken blood vessel -Vasoconstriction: angiotensin II mediates vasoconstriction -Platelet plug -Coagulation: blood clot formation due to platelets binding to collagen and a tissue factor that causes the platelets to coagulate which forms a mesh that leads to the formation of a fibrin mesh -Coagulation cascade: platelets stick together by sticking to collagen (integrin adhesion protein that binds to alpha v beta 3 ) in damaged vessels -When the platelet binds to the collagen the platelet gets activated and releases platelet activation factor (PAF) which causes more platelets to stick (positive feedback loop) -Thromboxane A2 (eicosanoid) gets released after the platelets have been activated because it is a vasoconstrictor and it mediates conversion of membrane lipids
What is erythropoiesis?
Production of red blood cells -25% of the cells developed in bone marrow are red blood cells (erythrocytes) -Red blood cells can live for about 4 months
What is leukopoiesis?
Production of white blood cells -75% of the cells developed in bone marrow are white blood cells (leukocytes) White blood cells don't live as long as red blood cells; they live about 6 hours
What happens when you have absent or abnormal nephrin or podocin?
Proteins leak across the glomerular filtration barrier into the urine
What is a complete blood count (CBC)?
Provides information about: -Hematocrit -Hemoglobin -Red cell count -Total white count -Differential white cell count -Platelets -Mean corpuscular volume (MCV) -Mean corpuscular hemoglobin (MCH) -Mean corpuscular hemoglobin concentration (MCHC)
What does the ascending aorta do?
Provides the upper extremities, such as the arms, head, and brain, with oxygenated blood
What do the ventricles do?
Pump blood out of the heart
What is Poiseuille's Law?
R = 8uL/pi r^4 u= viscosity L= length r= tube radius
What is the equation for resistance when dealing with the tube radius?
R= 1/r^4
What is clearance?
Rate at which a solute disappears from the body by excretion or by metabolism -Noninvasive way to measure glomerular filtration rate (GFR) -Inulin and creatine are used to measure GFR
How could diarrhea cause a temporarily elevated hematocrit?
Reduced fluid volume would cause the number of red blood cells by volume to become concentrated because plasma has been lost thus increasing the hematocrit
Movement can be?
Reflex (simple) or Voluntary (complex) or Rhythmic (intermediate) -Voluntary movement requires one to make a decision which occurs in the cerebral cortex
Where do collecting ducts drain?
Runs through the renal pyramids and drains urine through the renal papillae -Collecting ducts pass from the cortex through the medulla and drain into the renal pelvis -From the renal pelvis, the filtered and modified fluid (urine) flows into the ureter on its way to excretion
What is secretion in the kidneys?
Selectively removing molecules from the blood and adding them to the filtrate in the lumen of the tubules -Even though secretion and filtration are the same in movement, secretion is more selective
What does the Sinoatrial node do?
Sets the pace of the heartbeat at 70 bpm and signals the atria to contract -Acts as the pacemaker since it has the highest heart rate setting
What does Frank-Starling's law state?
Stroke volume increases as end diastolic volume (EDV) increases
What is the paracellular pathway?
Solutes move through junctions between epithelial cells -Substances pass through the cell-cell junction between two adjacent cells
What are muscle spindles?
Stretch receptors that are also known as intrafusal fibers -They are innervated by Gamma motor neurons -They are important for the stretch reflex (initiate stretch reflex)
What is tetanus and what causes it?
Tetanus (lockjaw) is a muscle spasm and it is caused by the bacterium Clostridium tetani. When a person gets infected the bacterium releases a protein neurotoxin called tetanospasmin
What does a whooshing sound mean?
That blood is coming in through a valve that it shouldn't be
What happens when there is a block between the sinoatrial node and the atrioventricular node?
That is called a complete heart block and its when you don't have an electrical signal reaching the ventricles. You will need to get a pacemaker to regulate the rate of your heart.
What does a clip clop sound mean?
That the valves are closing correctly
What does Bowman's capsule fluid pressure do?
The Bowman's capsule is an enclosed space, so the presence of fluid in the capsule creates a hydrostatic fluid pressure (P fluid) that opposes fluid movement into the capsule -Fluid filtering out of the capillaries must displace the fluid already in the capsule lumen -Hydrostatic fluid pressure in the capsule averages 15 mm Hg, opposing filtration
How does parasympathetic stimulation decrease heart rate?
The binding of acetylcholine to muscarinic receptors causes an influx of potassium and a decrease in the amount of calcium entering the cell. This leads to hyper polarization of the cell and the rate of depolarization decreases. Now the heart rate has slowed.
What is the outside of a kidney called?
The capsule
What are autorhythmic cells?
The cells that generate action potential repeatedly. These are the body's natural pacemakers. -They signal for contraction -They have smaller and fewer contractile fibers compared to contractile cells -Unlike contractile cells they do no have organized sarcomeres
What does the colloid osmotic pressure do?
The colloid osmotic pressure inside glomerular capillaries is higher than that of the fluid in Bowman's capsule -This pressure gradient is due to the presence of proteins in the plasma -The osmotic pressure gradient averages 30 mmHg and favors fluid movement back into the capillaries -This pressure opposes filtration
What is after load?
The combined load of end diastolic volume and arterial resistance during ventricular contraction
What rests right next to the pericardial sac?
The diaphragm which is why when you get indigestion it feels like its pushing on your heart
What is a differential white cell count?
The differential white cell count presents estimates of the relative proportions of the five types of leukocytes in a thin blood smear stained with biological dyes -Normal Ranges for Males and Females: Neutrophils: 50-70% Eosinophils 1-4% Basophils: < 1% Lymphocytes: 20-40% Monocytes: 2-8%
What is the distal nephron?
The distal tubule and its collecting ducts together
What is the first step in urine formation?
The filtration of plasma into the kidney tubule
What happens if resistance decreases in the afferent arteriole and hydrostatic pressure decreases on the glomerular side of the constriction?
The glomerular filtration (GFR) rate increases
What happens if resistance increases in the afferent arteriole and hydrostatic pressure decreases on the glomerular side of the constriction?
The glomerular filtration rate (GFR) decreases
What are contractile cells?
The heart muscle is made out of contractile and autorhythmic cells (pacemakers) -Contractile cells are striated fibers organized into sarcomeres
What is the pathway that goes from the sinoatrial node to the atrioventricular node?
The internodal pathway
What is the myogenic response?
The intrinsic ability of vascular smooth muscle to respond to pressure changes -When smooth muscle in the afferent arteriole wall stretches because of increased blood pressure, stretch sensitive ion channels open, and the muscle cells depolarize -Depolarization opens voltage gated calcium channels and the vascular smooth muscle contracts -Vasoconstriction increases resistance to flow, and so blood flow through the afferent arteriole diminishes -The decrease in blood flow decreases filtration pressure in the glomerulus -A decrease in the glomerular filtration rate (GFR) helps the body conserve blood volume a
How do you read the results on an electrocardiogram?
The mechanical events lag behind the electrical events (contraction follows action potential) -Electrocardiogram begins with atrial depolarization (start of P wave) and atrial contraction at the end of the P wave -PR segment goes through atrioventricular node and atrioventricular bundle -Q wave end: ventricular contraction begins and continues through T wave
What is the macula dense?
The modified portion of the tubule epithelium is a plaque of cells called the macula densa -Macula densa cells transport NaCl, and that increases in salt transport initiate tubuloglomerular feedback
What is the functional unit of the kidney?
The nephron
What is the filtration fraction?
The percentage of total plasma volume that filters into the tubule -100% of the plasma enters the afferent arteriole -80% immediately goes into the efferent arteriole and out through the peritubular capillaries -20% enters and filters through the nephron -During this filtration, more than 19% of the filtering fluid gets reabsorbed -So in conclusion, more than 90% of plasma that enters the kidneys returns to systemic circulation and less than 1% of fluid volume is excreted to the external environment
What is passive reabsorption?
The nitrogenous waste product urea has no active transporters in the proximal tubule but can move through the epithelial junctions by diffusion if there is a urea concentration gradient -When sodium and other solutes are reabsorbed from the proximal tubule, the transfer of osmotically active particles makes the ECF more concentrated than the filtrate remaining in the lumen -In response to the osmotic gradient, water moves by osmosis across the epithelium -When water is reabsorbed, the concentration of urea in the lumen increases -Once a concentration gradient for urea exists, urea moves out of the lumen into the ECF by transport through the cells (transcellular transport) or by the paracellular pathway
Once blood leaves the aorta where does it go?
The oxygenated blood either goes to the ascending arteries or the abdominal aorta
What is ejection fraction?
The percentage of end diastolic volume ejected with one contraction -Tha average ejection fraction is 52%
What is a hematocrit?
The percentage of total blood volume that is occupied by packed (centrifuged) red blood cells (erythrocytes) -Normal Ranges: Male 40-54% Female 37-47%
What does the epithelium of the Bowman's capsule do?
The portion of the capsule epithelium that surrounds each glomerular capillary consists of specialized cells called podocytes -Podocytes allow for filtration of fluid through the capillaries -Podocytes have long cytoplasmic extensions called foot extensions that extend from the main cell Foot processes wrap around the glomerular capillaries and interlace with one another, leaving narrow filtration slits closed by semiporous membrane -The filtration slit membrane contains several unique proteins, including nephrin or podocin
What is hydrostatic pressure?
The pressure exerted on the walls of the container by the fluid within the container -Hydrostatic pressure is proportional to the height of the water column The FORCE EXERTED ON THE CAPILLARY WALLS by the volume of fluid within the intravascular space.
What is hematopoiesis?
The process of blood cell formation -It begins early in the embryonic stage in the yolk sac at about the third week -In the beginning it starts at the extremities and as you get older it moves closer and closer to the core of the body -By the time you are an adult it is made in the pelvis, spine, ends of long bones, ribs, and skull
What is reabsorption in the kidneys?
The process of moving substances in the filtrate from the lumen of the tubule back into the blood flowing through peritubular capillaries
What is the hematocrit?
The ratio of the volume of red blood cells to the total volume of blood -It is expressed as a percentage
Why do endogenous EPO, rhEPO, and darbepoetin, which are made from the same gene, all have the same function but are different enough to be distinguished from one another?
The three hormones have sites that bind to and activate the EPO receptor, but they have different sizes or charges that cause them to separate during electrophoresis. Post-translational modifications allow proteins from the same gene to be altered so that they are different from one another.
How do you find the heart rate on an electrocardiogram?
The time between two P waves or two Q waves
What are the atrioventricular valves?
These valves are located between the atria and ventricles -Tricuspid valve on the right side, separates the right atrium from the right ventricle -Bicuspid (mitral) valve on the left side, separates the left atrium from the left ventricle
What are the semilunar valves?
These valves are located between ventricles and arteries -Aortic valve separates the left ventricle from the aorta -Pulmonary valve separates the pulmonary arteries from the right ventricle
What do alpha motor neurons do?
They activate a group of muscles called extrafusal muscle fibers (these are the ones that actually do the contraction)
Where are the kidneys located?
They are below the diaphragm at the level of the 11th and 12th ribs and retroperitoneal (behind the peritoneum)
What do myocardial muscle cells look like?
They are branched, have a single nucleus, and are attached to each other by specialized junctions known as intercalated disks -The muscle is also striated -Intercalated disks have gap junctions -Cardiac muscles have a lot of mitochondria cells
What happens to remnants of heme groups?
They are converted to bilirubin and excreted as bile
What happens to bilirubin metabolites?
They are excreted in urine -Elevated levels of bilirubin results in jaundice
Where are intrafusal fibers located?
They are found in muscle spindles
Where are proprioceptors located?
They are found in skeletal muscle, joint capsules, and ligaments
What do inactive platelets look like?
They are small disk-like cell fragments
What do beta 1 adrenergic receptors bind to?
They bind to epinephrine that comes from chromaffin cells in the adrenal glands or it will bind to norepinephrine that comes from sympathetic neurons that innervate the heart
What do activated platelets look like?
They develop a spiky outer surface and adhere to each other -These have activation of integrins (which can signal from outside to inside) which activate cellular factors inside the cytoplasm which causes the actin to polymerize and cause the spikes and adhesion
What happened to the kids who were making their own heroine?
They developed Parkinson's diseases because they were damaging their basal ganglia neurons which release dopamine -They had problems with memory, walking, maintaining normal hand movement without rigor, and cognitive movement
What do colony stimulating factors (CSF), interleukins, and stem cell factors do in hematopoiesis?
They help in the generation of all blood cell types and they mobilize the hematopoietic stem cells. They are produced by the endothelium and fibroblasts of bone marrow and leukocytes.
What are glomerular mesangial cells?
They lie between and around the glomerular capillaries and register how much blood is flowing through the afferent and efferent arterioles -They have cytoplasmic bundles of actin-like fragments that enable them to contract and alter blood flow through the capillaries -They secrete cytokines associated with immune and inflammatory processes -Disruptions of mesangial cell function has been linked to several disease processes in the kidney
What do Golgi tendon organs do?
They link the muscle and the tendon and it consists of sensory nerve endings interwoven among collagen fibers -They respond to stretch and are composed of free nerve endings
What are central pattern generators?
They maintain spontaneous repetitive activity such as running
What do albumins do?
They originate from the liver and they are major contributors to colloid osmotic pressure of plasma. They also carry various substances. -Transport fatty acids and steroids in the blood
What do globulins do?
They originate in the liver and lymphoid tissue. They are clotting factors, enzymes, antibodies, and carriers for various substances. -They transport lipids and antibodies for immunity
What do tonically active sensory neurons do?
They send information to the CNS from the muscle
What happens to red blood cells (erythrocytes) when placed in a hypertonic solution?
They shrink but the rigid cytoskeleton remains intact, creating a spiky surface -These cells are said to be crenated
What do the renal arteries do?
They supply blood to the kidneys -They branch off from the abdominal aorta
What happens to red blood cells (erythrocytes) when placed in a hypotonic solution?
They swell and lose their characteristic biconcave disk shape
What happens to the chordae tendineae and papillary muscles during ventricular contraction?
They tense which causes the atrioventricular valves to close
What happens during isovolumic ventricular contraction?
This is the first phase of ventricular contraction which pushes atrioventricular valves closed but does not create enough pressure to open semilunar valves
How does blood first leave the heart?
Through the aorta and coronary arteries -The coronary arteries provide oxygenated blood to the heart -The aorta provides oxygenated blood to the body
How does deoxygenated blood get from the right ventricle to the lungs?
Through the pulmonary arteries
How does oxygenated blood leave the lungs?
Through the pulmonary veins
What is the main goal of the heart?
To pump blood throughout the body and the blood does the following tasks: -Carries CO2 away from your tissues and oxygen to your tissues -Carries nutrients to your tissues and waste products away -Carries communication molecules, such as cytokines, peptides and hormones, throughout the body -It acts as a defense against pathogens because it carries cytokines, interleukins, and lymphokines -It also helps to maintain temperature homeostasis
Where is the base of the heart?
Top of the heart where the aorta and pulmonary arteries are
What does the abdominal aorta do?
Transports oxygenated blood to other arteries such as the hepatic artery, renal arteries, and descending arteries, and it provides oxygenated blood to the trunk of the body
True/False: Abnormal hemoglobin in sickle cell disease can cause red blood cells (erythrocytes) to change shape.
True
True/False: All autonomic reflexes are polysynpatic with at least one synapse in the CNS and another in the autonomic ganglion?
True
True/False: Amino acids are incorporated into new proteins.
True
True/False: Autorhythmic cells have an unstable membrane potential called pacemaker potential due to IF (funny) channels which are certain types of calcium channels that allow leakage of calcium into myocardial autorhythmic cells.
True
True/False: Autorhythmic cells use funny current channels to allow calcium to leak into the cell till you reach a certain threshold so an action potential can be fired.
True
True/False: Blood flows down a pressure gradient. As blood flows from the heart and throughout the body it has a pressure of about 95, but by the time it gets back to the heart the blood pressure is almost 0.
True
True/False: Blood is made from a common hematopoietic stem cell that is pluripotent.
True
True/False: Cardiac muscle contraction can be graded.
True
True/False: Catecholamines such as norepinephrine increase contractility.
True
True/False: Emotional reflexes are polysynaptic autonomic reflexes.
True
True/False: Extrafusal muscle fibers are normal contractile fibers.
True
True/False: Flow through a tube is inversely proportional to resistance.
True
True/False: Rhythmic movement is of intermediate complexity and is integrated in the spinal cord with higher center input required.
True an example of rhythmic movement is running. In rhythmic movement, you have to think about initiating and you have to think about terminating but in-between the motion is controlled by central pattern generators.
True/False: The amount of force generated is proportional to the number of active cross bridges.
True and it is determined by how much calcium is bound to troponin
True/False: The primary function of the proximal tubule is the isosmotic reabsorption of solutes and water.
True because filtrate leaving the proximal tubule has the same osmolarity as filtrate that entered
True/False: When it comes to regulation of heart rate by the autonomic system, the parasympathetic division dominates for the most part.
True because our heart rate isn't beating fast all the time which is what would be happening if the sympathetic division was primarily in control.
True/False: In a cardiac muscle fiber, the refractory period lasts almost as long as the entire muscle twitch.
True, and a long refractory period in a cardiac muscle prevents tetanus
True/False: Control of visceral muscle organs such as smooth and cardiac muscle is spontaneous.
True, and it is controlled by hormones or the autonomic division of the nervous system
True/False: The graded contraction (force) of the heart is proportional to the number of crossbridges between actin and myosin
True, and the number of crossbridges is due to the amount of calcium
True/False: The heart is encased within a membranous fluid-filled sac, the pericardium.
True, and the sac keeps the heart from rubbing against other bones and organs
True/False: Resistance is proportional to length of the tube.
True, as length increases so does resistance
True/False: Resistance is proportional to the viscosity or thickness of the blood
True, as viscosity increases so does resistance
True/False: Blood is composed of cells and plasma.
True, blood is actually a clear fluid with a whole bunch of red blood cells in it.
True/False: Only 20% of the plasma that passes through the glomerulus is filtered and less than 1% of filtered fluid is excreted.
True, but this is okay because throughout the day the blood is filtered multiple times (about 48) so eventually all of it will be filtered through.
True/False: The CNS integrates movement.
True, integrated coordinated responses require input from multiple regions of the brain
True/False: Reabsorption happens all the way through the nephrons of the kidneys starting at the proximal tubule.
True, it occurs in the proximal tubule, the loop of Henle, the distal tubule, and the collecting ducts.
True/False: The fluid that filters through the Bowman's capsule each day is almost identical in composition to plasma and nearly isosmotic.
True, its osmolarity is about 300 mOsM
True/False: The kidneys have one of the three portal systems in the body.
True, one nephron has two arterioles and two sets of capillaries that form a portal system.
True/False: Resistance is inversely proportional to the tube radius to the 4th power
True, resistance decreases as tube radium increases
True/False: Cardiac contractile cells are the muscle cells of the heart.
True, so they look like cardiac muscle
True/False: The kidneys are bean shaped organs that have a cortex and medulla.
True, the adrenal cortex and adrenal medulla
True/False: Flow through a tube is directly proportional to its concentration gradient.
True, the higher the pressure gradient the greater the fluid flow.
True/False: Only about 1/5 of the plasma that flows through the kidneys filters into the nephrons.
True, the remaining 4/5 of the plasma, along with most plasma proteins and blood cells, flows into the peritubular capillaries
True/False: Myocardial autorhythmic cells are not muscular cells.
True, they look differently than heart muscle as well
True/False: Cardiac muscle contraction can be graded, meaning it is not in an all or none fashion.
True, which is why the volume of blood is not the same when at the end of systole and when at the end of diastole
True/False: The female urethra is shorter than the male urethra.
True, which is why women are more prone to UTIs caused by the bacterium E.coli from the large intestine
What feeds deoxygenated blood from the body into the right atrium?
Two large veins: Inferior Vena Cava and Superior Vena Cava
When does the lub sound occur?
When the atrioventricular valves close and the semilunar valves open
What ensures one way flow of blood through the heart?
Two sets of heart valves: -Atrioventricular valves -Semilunar valves
What is micturition?
Urination
Which of the following structures in your cardiovascular system returns blood to the heart from the periphery?
Vena Cava
What determines end diastolic volume (EDV)?
Venous return -Venous return is affected by skeletal muscle pump, respiratory pump, and sympathetic innervation of veins
What do low levels of lymphocytes mean?
Viral infection
How do you measure stroke volume?
Volume of blood before contraction (end diastolic volume) - volume of blood after contraction (end systolic volume) = stroke volume -EDV - ESV = stroke volume
What is isovolumic ventricular relaxation?
Volume of blood in ventricles does not change
What are the two major components of an electrocardiogram?
Waves and segments
What is reciprocal inhibition?
When antagonist must relax due to contraction by the prime mover muscles (agonist) Ex: Polysynaptic reflex pathways cause an arm or leg to be pulled away from a noxious stimulus
When are the papillary muscles relaxed?
When blood is flowing into the ventricles, the chordae tendineae and papillary muscles are relaxed while the valve is held open
When does reabsorption occur in the kidneys ?
When proximal tubule cells transport solutes out of the lumen, and water follows by osmosis
What is hemolytic anemia?
When red blood cells (erythrocytes) rupture at an abnormally high rate
What is transepithelial transport (transcellular transport)?
When solutes move into and then out of epithelial cells -Substances cross apical and basolateral membranes of the tubule epithelial cells
What causes a state of shock?
When someone's blood pressure is too low
What is systole?
When the cardiac muscle contracts -During atrial systole the atria contracts which pushes any blood left in the atria into the ventricles and the atrioventricular valves close (the first heart sound occurs, lub) -During ventricular systole the ventricles finish contracting pushing semilunar valves open and blood is ejected into the arteries
What is diastole?
When the cardiac muscle relaxes -Beginning of the heart cycle the atria and ventricles are in diastole -The atria are filling with blood from the veins -The atrioventricular valves are open so the ventricles can fill -During atrial diastole all the valves shut, isometric contraction of the heart, atria relax and bloods flows in the atria -During ventricular diastole, ventricular relaxation and pressure drops but still remains higher than atrial pressure -Arterial blood flows back pushing semilunar valves closed and the second heart sound occurs (dub)
What is tachycardia?
When the heart is beating too fast
What is bradycardia?
When the heart is beating too slow
When does the dub or dup sound occur?
When the semilunar valves close and the atrioventricular valves open
When are the semilunar valves closed?
When the ventricles are relaxing and the atrioventricular valves are open
What is black water fever?
When urine is black due to hemolysis and degradation of hemoglobin
When do the atrioventricular valves open?
When ventricular pressure drops below below atrial pressure
What is differential?
When your blood smear is analyzed for different types and amounts of white blood cells (leukocytes) and red blood cells (erythrocytes)
Where does the filtration of blood in the kidneys occur?
Where the afferent arterioles and the glomerulus meet in the Bowman's capsule
How much of your kidney function must you lose before homeostasis begins to be affected?
three-fourths (3/4)
