Term
| What is the order of phases in the action potential of a ventricular cardiomyocyte? |
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Definition
0) Na+ channels open, depolarization
1) K+ channels open, slight repolarization
2) Ca++ channels open, plateau
3) K+ channels reopen, repolarization
4) K+ leak channels primary channels open |
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Term
| What are the primary differences between SA nodal pacemaker potential and cardiomyocyte action potentials? |
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Definition
1) phase 0 is Ca channels, not Na channels
2) phase 1-2 absent
3) funny channels (Na) contribute to slow potential rise during phase 4 |
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Term
| What is the normal autonomic tone present at rest (70 bpm)? |
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Definition
| Significant parsymp, not much symp. |
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Term
| What are the affects of atropine and propanolol? |
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Definition
| atropine blocks parasympathetics (ach), propanolol blocks symps (NE) |
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Term
| What are the 7 heart phases? |
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Definition
1) (Mitral valve closes) - isovolumetric contraction
2) (atrial valve opens) - rapid ejection
3) reduced ejectin
4) (atrial valve closes) - isovolumetric relaxation
5) (mitral valve opens) - rapid filling
6) reduced filling
7) atrial contraction |
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Term
| What is the formula for compliance? |
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Definition
| C = ^V/^P (how much pressure is needed to cause a given change in volume)? |
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Term
| What are primary contributers of pulse pressure? |
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Definition
| stroke volume, aortic compliance |
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Term
| What are the effects of NE on cardiac contractility (molecular effects, please!) ? |
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Definition
1) Increase activity of DHP receptor (increases Ca++ influx)
2) Decrease activity of Ca++ ATPase in SR - leads to greater relaxation during diastole and greater transient Ca++ release during stystole.
3) Phosphorylate myosin |
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Term
| What is the definition of afterload |
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Definition
| The force the ventricle must develop to eject blood (note that bigger heart lumens thus have higher afterloads at a given arterial presssure) |
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Term
| What are the 3 mechanisms that the heart compensates for increased afterload? |
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Definition
1) Frank-starling: First beat is reduced ejection, but next beat adds normal filling to increased end-systolic volume to give greater end diastolic volume -> increased ejection
2) Increased contractility (CNS driven?)
3) Cardiac hypertrophy over time |
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Term
| what are the factors that contribute to 1) systolic pressure and 2) diastolic pressure? |
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Definition
1) systolic: diastolic pressure, aortic compliance, stroke volume
2) diastolic: systolic pressure, arteriole runoff rate and time |
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Term
| Which layer has unique properties in a large vein? |
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Definition
| The tunica adventitia - not only is it very thick, but there are smooth muscle bundles that run longitudinally |
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Term
| Why does the respiratory pump increase cardiac output? |
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Definition
| It decreases the intrathoracic pressure, which increases the transmural pressure (Pi-Po) of the central venous system, increasing the central blood volume and thus the end diastolic volume of the heart ventricles. |
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Term
| What is the difference between postcapillary and muscular venules? |
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Definition
| Postcapillary = no smooth muscle in media |
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Term
| What contributes to capillary ultrafiltration rate? |
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Definition
1) Hydrostatic pressure drive
difference between cap. and interstit. hydrostatic pressures
2) Osmotic drive
Difference between colloid osmotic pressures - this drive can be diminished if the capillary is somewhat permeable to protein
3) kinetic limitations - determined by conductivity and surface area of capillaries |
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Term
| What are the two drivers of baroreceptor firing? |
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Definition
| Pulse pressure and mean arterial pressure |
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Term
| What is the difference in sensing between the baroreceptor and cardiopulmonary reflexes? |
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Definition
Baroreceptor is a pressure sensor in an artery
Cardiopulmonary is a stretch (volume) sensor of central blood volume (~blood in heart and lungs) |
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Term
| What is arginine vasopressin? |
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Definition
| ADH - increases water saving |
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Term
| What hormones do the atrium and ventricle release when they are stretched? |
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Definition
atrium - atrial natriuretic hormone
ventricle - brain ""
Both increase Na excretion |
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Term
| What is the most powerful factor in pressure regulation in the long term? |
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Definition
| Pressure diuresis - increases GFR and thus increases Na and H20 secretion |
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Term
| What are the effects of deep and superficial pain on blood pressure? |
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Definition
| Autonomics respond to deep pain by decreasing blood pressure, to superficial by increasing "" |
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Term
| What is the pearl diver reflex? |
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Definition
| breath-holding + chemicals indicating hypoxia/acidemia/hypercapnia = inreasedc sns tone which increases TPR, increased pns tone which decreases HR - this is an oxygen-saving mechanism |
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Term
| Why are the following vasodialators: adenosine, K+, H+? |
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Definition
ADP-> AMP -> adenosine
AP -> K+ out
H+ from CO2, lactic acid |
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Term
| What is myogenic regulation of local blood flow? |
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Definition
| Automatic local compensatory response to changes in transmural pressure in arterioles |
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Term
| What is the mechanism by which shear stress turns on NO synthase? |
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Definition
| It causes Ca++ release via |
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Term
| What are the 3 effects that contribute to diastolic pressure |
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Definition
1) arteriolar dilation
2) time for runoff
3) systolic pressure |
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Term
What does atropine do?
Propanolol?
Phentolamine? |
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Definition
Blocks muscarinic cholinergic - increases conduction velocity and heart rate
Blocks adrenergic - lowers heart rate, conduction velocity, and contractility
Phentolamine - a-adrenergic blocker - decreases systemic vascular resistance |
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Term
| What is the material that stains brownish in HE prep of cardiomyocytes? |
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Definition
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Term
| What is the material that stains brownish in HE prep of cardiomyocytes? |
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Definition
| Hemosiderin - RBC breakdown product |
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Term
| To which layers do the internal and external elastic laminae belong in muscular arteries? |
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Definition
| to intima and adventitia - media stands alone! |
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Term
| In which organs are fenestrated caps found? |
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Definition
| Endocrine, intestine, gall bladder |
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Term
| In which organs are discontinuous caps found? |
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Definition
| liver, spleen, bone marrow |
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Term
| What are characteristics of post cap. venuoles? |
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Definition
| very few layers, not much muscle, |
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Term
| True or false - large veins can have internal elastic lamina? |
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Definition
|
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Term
| Which cells secrete elastin? |
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Definition
| Usu. fibroblasts - unless lamellar, in wich case smooth muscle |
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Term
| What does old chondrocytes accumulate |
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Definition
|
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Term
| What's found inside a volkman's canal? |
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Definition
| Endosteum and blood vessels |
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Term
| Are megakaryocytes multinucleated |
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Definition
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Term
| What are the zones of cartilage in endochondral bone formation? |
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Definition
1) zone of reserve
2) zone of proliferation
3) zone of hypertrophy
4) zone of calcified cartilage
5) zone of resorption |
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Term
| What are distinguishing features of monocytes? |
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Definition
1) indented large nucleus
2) maybe primary granules
3) no specific granules
4) "lacy" nucleus |
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Term
| What is the name of the epithelium that covers the outside surface of the lung? |
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Definition
|
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Term
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Definition
| This is the esonophilic line at the basal body area of the cilia (usu of pseudostratified eptithelium) |
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Term
| What forms the blood-brain barrier? |
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Definition
| Endothelial cells which form tight junctions. Astrocytes only maintain barrier by giving "instructions" to endothelium |
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Term
| What is the muscle organization in the non-esophagus gut tube? |
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Definition
| Inner circular, outer longitudinal |
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Term
| note to self: learn how to recognize nerves!!!!! and their different types |
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Definition
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Term
| What type of nerve causes dilation of skin veins? |
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Definition
| Sympathetic cholinergic - releases vasoactive intestinal peptide |
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Term
| What is the effect of exercise on TPR? |
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Definition
| Generally decreases if a large muscle is being exercised - reactive hyperemia causes local vasodilatation, which is often enough to reduce TOTAL resistance, even with concurrent sympathetic stimulation |
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Term
| What is the effect of (compensated) dynamic excercise on systolic and diastolic pressure? |
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Definition
Systolic increase (large stroke volume, rate increases)
Diastolic decrease (runoff rate increase) |
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Term
| What is the effect of static exercise on Ps and Pd and Pp? |
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Definition
Ps goes up
Pd goes up (TPR goes up - arterioles are pinched)
Pp goes up (increased stroke volume) |
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Term
| What pressure measurement is a decent proxy for coronary blood flow? |
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Definition
| Diastolic pressure- because cardiac profusion is obstructed by contraction of cardiac muscles |
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