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31 Cards in this Set
- Front
- Back
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In an anemic cat with a hematocrit of 15%, is the viscosity of blood greater than, equal to, or less than the viscoscity of plasma?
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Greater than.
Blood is thicker than water, yo, even if there is less of it. |
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If the SA node depolarizes at time 0 sec, does the AV node begin depolarizing before or after the entire left atrium is depolarized?
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Before.
AV node begins depolarizing @ 0.03 sec; The signal isn't slowed until LATE in the AV node. Atrial depolarization takes 0.09 sec. |
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Is depolarization of the AV node complete before, at the same time, or after the entire left atrium is depolarized?
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After.
I don't get this one since AV node apparently takes 0.12 sec to depolarize and atrial depolarization takes 0.09 sec. |
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Is repolarization of the AV node complete before, at the same time, or after ventricular depolarization is complete?
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After.
Pacemaker cells take 0.2 sec (SA) and ~0.3 sec (AV) to repolarize. By this time, all ventricular cells in a normal heart will have depolarized. |
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Which of the following is NOT consistent with hyperkalemia?
a) first degree AV node block b) bradycardia c) tall spiked T wave d) atrial standstill e) atrial fibrillation |
Atrial fibrillation
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An English Bulldog presents with signs of fatigue and ascites. On thoracic auscultation you detect a murmur. You decide this murmur is consistent with pulmonic stenosis.
Is this a systolic, diastolic, or continuous murmur? |
Systolic.
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An English Bulldog presents with signs of fatigue and ascites. On thoracic auscultation you detect a murmur. You decide this murmur is consistent with pulmonic stenosis.
Where is this murmur heard on physical exam? P, A, or M? |
P (pulmonary valve).
Left 3rd IC space at costo-chondral junction. |
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In the typical amount of time it takes blood to traverse a capillary, diffusional exchange takes place over distances of up to:
a) 100um b) 1mm c) 100mm d) 1cm |
a) 100um
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How much longer is the duration of a ventricular AP compared to a skeletal muscle AP?
a) 1x b) 10x c) 50x d) 100x |
d) 100x
actually closer to 200 to 250x |
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What effect would a Ca channel blocker have upon stroke volume?
a) increased b) decreased c) no change |
b) decreased
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What effect would a Ca channel blocker have upon peak systolic pressure in the ventricle? Assume no change in preload or afterload.
a) increased b) decreased c) no change |
b) decreased
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What effect would a Ca channel blocker have upon End diastolic volume? Assume no change in preload or afterload.
a) increased b) decreased c) no change |
Ca blockers would decrease contractility (no change to EDV) and decrease HR. THis decreased HR would provide more fill time and increase EDV (methinks). However, the person put Increased but this was wrong...
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What effect would a Ca channel blocker have upon end systolic volume? Assume no change in preload or afterload.
a) increased b) decreased c) no change |
a) increased
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What effect would a Ca channel blocker have upon cardiac output? Assume no change in preload or afterload.
a) increased b) decreased c) no change |
not sure. person put no change (wrong).
I would guess decrease CO since you'd have decreased contractility. |
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Differences between contraction of skeletal muscle and cardiac muscle include all of the following except:
a) External Ca is required for skeletal muscle contraction. b) Neurotransmitters are not needed for depolarization to threshold in cardiac cells but are necessary in skeletal muscle cells. c) APs spread from cell to cell throughout the heart but are confined to one cell in skeletal muscle. d) An insufficient amount of Ca is released from the SR to fully activate the contractile machinery in cardiac muscle unless Ca enters through slow Ca channels to trigger additional Ca release. e) Only APs in skeletal muscles are blocked by tetrodotoxin (blocks voltage-dependent Na channels). |
DIdn't put an answer. I'm pretty sure it's A.
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Which of the following is true concerning the rapid ejection phase of the cardiac cycle for the left ventricle?
a) the mitral valve is open b) aortic pressure is rising c) the ventricle will experience its minimal volume d) the first heart sound occurs throughout this phase e) the QRS occurs during this phase |
B) aortic pressure is rising
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Which of the following is not an explanation for why excessive hypertrophy of the ventricle is deleterious.
a) hypertrophy hinders the ability of the heart rate to increase b) the thickened wall reduces compliance which hinders filling c) coronary circulation cannot meet the metabolic needs of the hypertrophied ventricle d) the systolic pressure-volume curve is shifted down and to the right e) enlarged chambers interfere w/valve action and narrow the outflow tract |
a) hypertrophy hinders the ability of the HR to increase
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Which of the following would NOT cause a systolic murmur?
a) Ventricular septal defect b) pulmonic stenosis c) tricuspid insufficiency d) PDA e) mitral stenosis |
Mitral valve stenosis
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Total block of the AV node would:
a) result in T waves and QRS complexes that are desynchronized b) lead to sinus arrest c) stop the atria from contracting d) cause the atria and ventricles to beat at different frequencies e) have no effect on CO |
no answer here but I think it's d) cause the atria and ventricles to beat at different frequencies
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Phase 4 of the AP in the SA node cell...
a) is associated w/diastolic repolarization b) is unstable because of a progressive increase in Na conductance c) is closer to the equilibrium potential for Na than K d) will be hyperpolarized by NE e) will have its rate of depolarization increased by ACH |
B) is unstable because of a progressive increase in Na conductance
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Choose the statement that ain't right:
a) When CO is measured by the thermodilution technique, blood flow is inversely proportionate to the temp difference between measured temp and normal body temp. b) central venous pressure is a measure of right ventricular preload. c) pulmonary wedge pressure is a measure of left ventricular preload. d) ejection fraction is used to estimate ventricular compliance. e) mean aortic pressure provides an estimate of afterload. |
d) ejection fraction is used to estimate ventricular compliance.
The ejection fraction is a crude estimate of contractility but of great clinical value. |
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Administration of digitalis (a cardiac glycoside)...
a) would inhibit the Na/K ATP-ase pump and decrease contractility. b) would have no effect on the fast Na channels. c) impairs the Na/Ca exchanger in the T tubules and cell membrane. d) would decrease parasympathetic nerve activity. e) would shorten the refractory period in AV node cells, which is important for high heart rates. |
I think it's B but I dunno right off the top of my head...
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Which of the following will increase SV if all other parameters remain unchanged?
a) decreasing left atrial pressure. b) decreasing aortic pressure. c) decreasing contractility. d) increasing HR. e) decreasing ventricular compliance. |
b) decreasing aortic pressure
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Choose the FALSE statement. Of the various types of vessels in the systemic circulation, capillaries..
a) have the shortest length. b) have the slowest velocity of blood flow. c) have the lowest mean blood pressure. d) have the greatest total xs area. e) have the greatest # of vessels. |
c) have the lowest mean blood pressure.
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Which of the following would not be an expected pathologic consequence of aortic regurgitation?
a) Pulmonary edema b) Increased left atrial pressure. c) moderate left ventricular hypertrophy d) marked right ventricular hypertrophy e) atrial fibrillation |
d) marked right ventricular hypertrophy
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The end diastolic volume in the normal heart is primarily determined by:
a) the contractility of the ventricle b) the diameter of the mitral valve orifice c) the pressure in the left atrium d) the aortic pressure e) the HR |
C) the pressure in the left atrium
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Choose the correct statement below (can be many):
Regarding the ventricular (fast) AP... a) Closure of the h gate is voltage triggered and causes phase 0 to end. b) Opening of the slow Ca channels interrupts early partial repolarization. c) In the relative refractory period, during the early half of phase 3 repolarization, APs can be propagated because m gates are still open. d) The period of supernormal excitability is associated with the T wave of the ECG and the membrane can be depolarized by a stimulus that is smaller than normal. e) Membrane permeability to potassium increases during phase 3. |
A, B, D, and E
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Choose the correct statement below (can be many):
Starling's law of the heart: a) Provides a mechanism that matches the outputs of R and L ventricles. b) Depends on autonomic nerve mediated (sympathetic and parasympathetic) changes in cardiac contractility. c) States that an increase in end diastolic pressure increases stroke volume. d) Accounts for most of the increase in cardiac output duing mild to moderate exercise. e) Provides a mechanism to explain why CO is independent of afterload over a wide range of normal arterial pressures. |
A, C, and E
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Choose the correct statement below (can be many):
The AV node: a) in the lower His bundle region has intrinsic pacemaker activity. b) slows AP conduction velocity in the specialized conduction system of the heart. c) is the only conduction pathway between the atria and ventricles because elsewhere the atria and ventricles are separated by the pericardial sac. d) refractory period is lengthened by parasympathetic input. e) is responsible for phase 2 of the ventricular (fast) AP. |
A, B, and D
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Choose the correct statement below (can be many):
Currents caused by opening of which of the following channels contribute to the diastolic depolarization of cardiac pacemaker cells? a) Na channels b) Cl channels c) Ca channels d) K channels e) HCO3 channels |
A and C
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Choose the correct statement below (can be many):
During the cardiac cycle... a) the 1st heart sound is caused by closure of the pulmonic and aortic valves. b) the ejection fraction is increased by sympathetic stimulation. c) the QRS wave of the ECG corresponds in timing w/the onset of ventricular contraction. d) atrial systole is responsible for more than half of ventricular filling at a heart rate of 120 bpm (dog). e) Ventricular systole occurs after the 2nd heart sound. |
B and C
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