Question 1

Which of the following best describes the function of the pericardial cavity surrounding the heart?

Accepted Answer

It contains fluid that decreases friction between the heart and surrounding structures during contraction.

Question 2

A patient presents with a swishing sound heard during auscultation, indicating blood regurgitation through a valve. Which condition is most likely responsible?

Accepted Answer

Incompetent (insufficient) valve

Question 3

During ventricular systole, which heart valves are closed?

Accepted Answer

Atrioventricular (AV) valves

Question 4

Which equation correctly calculates stroke volume (SV) given end diastolic volume (EDV) and end systolic volume (ESV)?

Accepted Answer

$$SV = EDV - ESV$$

Question 5

A patient with persistent high blood pressure is at risk for which change in the heart’s function?

Accepted Answer

Increased afterload, resulting in increased end systolic volume and reduced stroke volume

Question 6

Which structure is responsible for initiating the heartbeat and is known as the heart’s pacemaker?

Accepted Answer

Sinoatrial (SA) node

Question 7

Which of the following is a key difference between cardiac and skeletal muscle contraction?

Accepted Answer

Cardiac muscle relies on both sarcoplasmic reticulum and extracellular $$Ca^{2+}$$ for contraction.

Question 8

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

Accepted Answer

It pumps blood into the systemic circuit, which requires greater pressure due to higher resistance.

Question 9

Which sequence correctly represents the order of electrical conduction through the heart?

Accepted Answer

SA node → AV node → AV bundle → Bundle branches → Purkinje fibers

Question 10

A patient’s ECG shows an elevated S-T segment. What is the most likely clinical implication?

Accepted Answer

Cardiac ischemia

Question 11

Which formula correctly calculates cardiac output (CO)?

Accepted Answer

$$CO = HR 	imes SV$$

Question 12

Which of the following would most likely increase preload and thus stroke volume?

Accepted Answer

Slow heartbeat and exercise

Question 13

Which heart sound is associated with the closing of the semilunar valves?

Accepted Answer

Second sound (dup)

Question 14

Which of the following is a positive inotropic agent that increases contractility?

Accepted Answer

Epinephrine

Question 15

A patient with hyperkalemia is at risk for which cardiac abnormality?

Accepted Answer

Heart block and cardiac arrest

Question 16

Which congenital heart defect involves mixing of oxygen-poor and oxygen-rich blood due to a septal defect?

Accepted Answer

Tetralogy of Fallot

Question 17

Which of the following best describes the Frank-Starling law of the heart?

Accepted Answer

The higher the preload, the higher the stroke volume.

Question 18

Which of the following is true regarding the action potential in contractile cardiac muscle cells?

Accepted Answer

It includes a plateau phase due to slow $$Ca^{2+}$$ influx, prolonging contraction.

Question 19

Which of the following would most likely cause bradycardia in a non-athlete?

Accepted Answer

Low body temperature or PSNS activation

Question 20

Which of the following is a consequence of left-sided heart failure?

Accepted Answer

Pulmonary congestion and edema in lung tissue

The Heart: Structure, Function, and Physiology

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