Question 1

Which of the following best describes the unique structural features of cardiac muscle cells compared to skeletal muscle cells?

Accepted Answer

Cardiac muscle cells are short, branched, possess sarcomeres, and have more mitochondria.

Question 2

A patient is diagnosed with a defect in the interatrial septum resulting in a persistent foramen ovale. Which of the following is the most likely consequence?

Accepted Answer

Decreased oxygenation of blood due to mixing of oxygenated and deoxygenated blood.

Question 3

Which layer of the heart is primarily responsible for the force of contraction?

Accepted Answer

Myocardium

Question 4

During ventricular systole, which valves are open and which are closed?

Accepted Answer

AV valves are closed; semilunar valves are open.

Question 5

Which of the following best explains why cardiac muscle cells have more mitochondria than skeletal muscle cells?

Accepted Answer

Cardiac muscle cells require more ATP for continuous contraction.

Question 6

If the left AV (bicuspid/mitral) valve fails to close properly, what is the most likely physiological outcome?

Accepted Answer

Blood will regurgitate into the left atrium during ventricular contraction.

Question 7

Which of the following equations best represents cardiac output ($$CO$$)?

Accepted Answer

$$CO = HR 	imes SV$$

Question 8

A blockage in the pulmonary arteries would most directly affect which circuit of the circulatory system?

Accepted Answer

Pulmonary circuit

Question 9

Which structure prevents backflow of blood from the right ventricle into the right atrium?

Accepted Answer

Right AV (tricuspid) valve

Question 10

Which of the following is a function of the pericardial fluid?

Accepted Answer

Reduces friction between the heart and pericardium during contraction.

Question 11

Which of the following best describes the flow of blood through the heart starting from the systemic veins?

Accepted Answer

Superior/inferior vena cava → right atrium → right ventricle → pulmonary trunk → pulmonary arteries → lungs → pulmonary veins → left atrium → left ventricle → aorta

Question 12

Which of the following is TRUE regarding the coronary circulation?

Accepted Answer

It supplies oxygenated blood to the myocardium.

Question 13

Which of the following statements about the automaticity and autorhythmicity of cardiac cells is correct?

Accepted Answer

Cardiac cells can generate their own action potentials without external stimulation.

Question 14

A patient with a defect in the ductus arteriosus (ligamentum arteriosum) after birth is at risk for which of the following?

Accepted Answer

Abnormal mixing of blood between the pulmonary trunk and aorta.

Question 15

Which of the following best describes the function of the semilunar valves?

Accepted Answer

Prevent backflow of blood from arteries into the ventricles.

Question 16

Which of the following is the correct sequence of layers from the outermost to the innermost in the heart wall?

Accepted Answer

Epicardium → Myocardium → Endocardium

Question 17

Which of the following is TRUE regarding the pulmonary circuit?

Accepted Answer

It carries deoxygenated blood from the right ventricle to the lungs.

Question 18

Which of the following best explains why the left ventricle has a thicker wall than the right ventricle?

Accepted Answer

The left ventricle pumps blood into the systemic circuit, which requires higher pressure.

Question 19

Which of the following is a direct result of the presence of intercalated disks in cardiac muscle cells?

Accepted Answer

Rapid transmission of electrical signals between cells.

The Heart: Structure and Function in the Cardiovascular System

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