Question 1

Which of the following statements about the membrane potential of cardiac contractile cells is INCORRECT?

Accepted Answer

Conductive cells are depolarized to $$+35\ \mathrm{mV}$$ and contractile cells to $$+65\ \mathrm{mV}.$$

Question 2

During the plateau phase of the cardiac contractile cell action potential, which ion channel is primarily responsible for the sustained depolarization, and what is the physiological benefit?

Accepted Answer

Slow calcium channels are responsible for the prolonged depolarization plateau phase, which prevents summation and premature contractions.

Question 3

Which of the following best describes the function of the fibrous skeleton of the heart?

Accepted Answer

It anchors the heart valves and provides electrical insulation between the atria and ventricles.

Question 4

Which statement about the pericardium is TRUE?

Accepted Answer

The fibrous pericardium protects the heart and maintains its position in the thorax.

Question 5

Which of the following is a correct statement regarding the cardiac skeleton?

Accepted Answer

It serves as the point of attachment for the valves of the heart.

Question 6

Which of the following correctly describes the effect of sympathetic stimulation on the heart?

Accepted Answer

Sympathetic stimulation causes norepinephrine release that shortens the repolarization period, increases the rate of depolarization and contraction, thereby increasing the heart rate.

Question 7

How do cardiac muscle cells primarily meet their energy needs?

Accepted Answer

Cardiac muscle metabolism is normally entirely aerobic, relying on fatty acids and glycogen stored within the cells.

Question 8

During a normal cardiac cycle, how many of the four heart chambers contract simultaneously?

Accepted Answer

2

Question 9

Which of the following occurs during ventricular contraction?

Accepted Answer

The semilunar valves open and the AV valves close.

Question 10

Which statement about heart valves is TRUE?

Accepted Answer

All of these are correct.

Question 11

Which of the following is correct regarding cell-to-cell contacts in cardiac muscle fibers?

Accepted Answer

Desmosomes within the intercalated discs prevent cardiac muscle fibers from pulling apart.

Question 12

Which two processes within the heart occur due to pressure changes associated with the cardiac cycle?

Accepted Answer

Opening and closing of heart valves to ensure there is no backflow of blood and unidirectional movement of blood through the heart chambers.

Question 13

The papillary muscles attach to the cusps of the atrioventricular valves by means of the:

Accepted Answer

Tendinous cords (chordae tendineae).

Question 14

The internal wall surface of each ventricle displays large, smooth, irregular muscular ridges called:

Accepted Answer

Trabeculae carneae.

Question 15

The serous fluid within the pericardial cavity works to:

Accepted Answer

Lubricate membranes of the pericardium.

Question 16

Which correctly states the function of coronary arteries?

Accepted Answer

Coronary arteries distribute blood containing nutrients and oxygen to the heart muscle cells.

Question 17

Which of the following is a function of plasma proteins in blood?

Accepted Answer

They maintain osmotic pressure and transport substances.

Question 18

Which of the following is TRUE regarding erythropoiesis?

Accepted Answer

Erythropoiesis is stimulated by hypoxia, which increases erythropoietin production.

Question 19

Which of the following best describes the process of hemostasis?

Accepted Answer

Hemostasis involves vasoconstriction, platelet plug formation, and coagulation.

Question 20

A patient with type O negative blood requires a transfusion. Which blood type is safest to use and why?

Accepted Answer

Type O negative, because it lacks both A and B antigens and the Rh antigen, minimizing risk of hemolytic reaction.

Study Guide: Cardiac Physiology and Blood – Structure and Function

Study Guide - Practice Questions

Study Guide - Flashcards