practice exam 1

Question 1

Inflammatory pathways promote thrombosis, which is responsible for myocardial infarction and most strokes.
a. true b. false

Answer 1

a. true

Question 2

What is released from the endothelial wall, that promotes vasodilatation and limits platelet extension?

a. thromboxane A2
b. prostaglandin F 2 α
c. prostacyclin (PGI2)
d. norepinephrine

Answer 2

c. prostacyclin (PGI2)

Question 3

A traumatized vessel will constrict; most of the constriction is due to which of the following?

a. SNS reflex contraction
b. thromboxane A2 release from platelets
c. local myogenic spasm 
d. prostacyclin release from the endothelium

Answer 3

c. local myogenic spasm

Question 4

Which of the following is effective at dissolving blood clots?

a. plasmin
b. throboxane A2
c. prostacyclin
d. heparin

Answer 4

a. plasmin

Question 5

What is the key step in blood coagulation?

a. the release of platelet granule contents
b. the activation of factors X and V
c. sympathetic stimulation of vascular smooth muscle
d. the conversion of fibrinogen to fibrin

Answer 5

d. the conversion of fibrinogen to fibrin

Question 6

Fibrinogen and prothrombin along with factors VII, IX, X are produced by which organ?
a. liver b. lungs c. spleen d. kidney

Answer 6

a. liver

Question 7

Concerning Ca++ role in blood clotting, which of the following statements is true?

a. required at all intrinsic pathway steps
b. only required at all extrinsic pathway steps
c. required at all steps except the 1st two intrinsic steps
d. required only to allow thrombin to convert fibrinogen to fibrin

Answer 7

c. required at all steps except the 1st two intrinsic steps

Question 8

Compared to a typical ventricular muscle cell, which of the following is a characteristic of the SA node?

a. only fast Na+ channels operational
b. longer plateau
c. lacks a stable resting polarized state
d. more negative resting membrane potential

Answer 8

c. lacks a stable resting polarized state

Question 9

At a normal resting membrane potential of -85 mV, which of the following ions is closest to its Nernst equilibrium potential?
a. Na+ b. Ca++ c. K+ d. Cl-

Answer 9

c. K+

Question 10

A 2-3 X elevation in extracellular fluid of what ion can cause flaccidity and weakness of cardiac muscle in part by decreasing the resting membrane potential.
a. Na+ b. Ca++ c. K+ d. Cl-

Answer 10

c. K+

Question 11

If end diastolic volume = 160 ml and end systolic volume = 120 ml; what is the ejection
fraction?
a. 25% b. 50% c. 75% d. undeterminable

Answer 11

a. 25%

Question 12

What percentage of blood from the atrial to the ventricle is actively pumped?
a. 25-30% b. 45-55% c. 70-75% d. 95-100%

Answer 12

a. 25-30%

Question 13

Norepinephrine binds to which cardiac receptors?

a. alpha b. beta c. muscarinic d. nicotinic

Answer 13

b. beta

Question 14

At rest, if you block both divisions of the autonomic nervous system, which of the following changes would occur?

a. both HR and strength of contraction will decrease
b. both HR and strength of contraction will increase
c. HR will increase and strength of contraction will decrease d. HR will decrease and strength of contraction will increase

Answer 14

c. HR will increase and strength of contraction will decrease

Question 15

What allows the action potential to spread from one cardiac cell to an adjacent cardiac cell, and therefore allows the heart to behave as a syncytium?

a. purkinje system  
b. intercalated discs
c. type C nerve fibers
d. AV node

Answer 15

b. intercalated discs

Question 16

20. Which of the following create only a diastolic murmur?
    a. aortic stenosis
    b. pulmonic stenosis
    c. mitral stenosis
    d. patent ductus arteriosis

Answer 16

c. mitral stenosis

Question 17

21. Reperfusion injury following infarction is primarily associated with which of the following?
    a. overdrive suppression
    b. arrhythmias
    c. sympathetic activity
    d. free radical production

Answer 17

d. free radical production

Question 18

22. If the left atrial pressure is 7 mmHg., the left ventricular pressure is 100 mmHg., and the aortic blood pressure is 106 mmHg., what is the status of the valves on that side of the heart?
    a. mitral and aortic valves closed
    b. mitral valve closed and aortic valve open
    c. mitral valve open and aortic valve closed
    d. mitral and aortic valves open

Answer 18

a. mitral and aortic valves closed

Question 19

Increased stretch on the ventricular fibers during filling, have what effect on calcium influx into the ventricular cells?
a. increase b. decrease c. no effect

Answer 19

a. increase

Question 20

Which of the following has a positive inotropic effect on the ventricle.

a. acetylcholine
b. thyroxine
c. atrial natriurectic peptide
d. alcohol

Answer 20

b. thyroxine

Question 21

A wave of repolarization moving toward the positive recording electrode would create what type of deflection?
a. positive deflection b. negative deflection c. no appreciable deflection

Answer 21

b. negative deflection

Question 22

When does myocardial blood flow peak in the left ventricle?

a. at the onset of diastole
b. mid systole
c. at the onset of systole
d. mid diastole

Answer 22

a. at the onset of diastole

Question 23

Which of the following statements regarding a prolonged QT interval (increased incidence of sudden cardiac death) is true?

a. females are more susceptible than males
b. males are more susceptible than females
c. children are more susceptible than adults
d. adults are more susceptible than children

Answer 23

b. males are more susceptible than females

Question 24

If the sympathetic nerves to the heart are cut, and then the SNS is stimulated, heart rate will
still increase, why?
a. intrinsic autoregulation will compensate
b. due to local release of sympathetic neuropeptides
c. circulating norepinephrine/epinephrine from the adrenal medulla
d. adrenergic parasympathetic innervation dominates

Answer 24

c. circulating norepinephrine/epinephrine from the adrenal medulla

Question 25

Under resting conditions, what percentage of oxygen is extracted by the myocardium from the perfusing coronary blood flow? a. 20% b. 50% c. 70% d. 90%

Answer 25

c. 70%

Question 26

The preferred energy substrate of ventricular cardiac cells is which of the following? a. amino acids b. glucose c. pyruvate d. fatty acids

Answer 26

d. fatty acids

Question 27

At a constant operating pressure what happens to the wall tension as the radius of that chamber decreases? a. increases b. decreases c. stays constant

Answer 27

b. decreases

Question 28

No consistent relationship of P waves to QRS complexes describes which of the following? a. 1st o AV block b. 2nd o AV block c. 3rd o AV block d. bundle branch block

Answer 28

c. 3rd o AV block

Question 29

If you block fast Na+ channels in a typical cardiac muscle cell using “tetradotoxin”, what will be observed? a. the cell is unable to depolarize b. depolarization is slowed c. the cell will die d. the cell will depolarie, but is unable to contract

Answer 29

b. depolarization is slowed

Question 30

As heart rate increases, cycle length decreases, which of the following statements is true? a. systole and diastole both shorten by a equal amount b. diastole shortens more than systole c. systole shortens more then diastole d. only diastole shortens, systole stays constant

Answer 30

b. diastole shortens more than systole

Question 31

Most of the energy consumed by the heart for work is utilized for which of the following? a. pressurization of blood by the ventricles b. acceleration of blood out of the ventricles c. closure of the valves d. production of heat

Answer 31

a. pressurization of blood by the ventricles

Question 32

An inverted T wave is associated with which of the following? a. infarction b. left ventricular hypertrophy c. first degree AV block d. ischemia

Answer 32

d. ischemia

Question 33

What is the major function of the AV node? a. normal pacemaker of the heart b. delays the wave of depolarization from the atria to the ventricle c. rapidly transmits the wave of depolarization from the atria to the ventricle d. allows the ventricle to depolarize as a unit

Answer 33

b. delays the wave of depolarization from the atria to the ventricle

Question 34

Which of the following changes in ion flux will slow the heart rate? a. increase in Na+ influx b. increase in K+ efflux c. increase in Ca++ influx d. decrease in K+ efflux

Answer 34

b. increase in K+ efflux