$$SV = 130 \text{ mL} - 60 \text{ mL} = 70 \text{ mL}$$

Question 1

Which layer of the heart wall is responsible for generating the force of contraction and contains spiral arrangements of muscle fibers?

Accepted Answer

Myocardium

Question 2

During ventricular systole, which valves are closed to prevent backflow into the atria?

Accepted Answer

Tricuspid and Mitral valves

Question 3

A patient presents with a QRS complex duration longer than 100 ms on their ECG. What does this most likely indicate?

Accepted Answer

Ventricular depolarization delay

Question 4

Which equation correctly represents cardiac output (CO)?

Accepted Answer

$$CO = SV 	imes HR$$

Question 5

If a patient has an end-diastolic volume (EDV) of 130 mL and an end-systolic volume (ESV) of 60 mL, what is their stroke volume (SV)?

Accepted Answer

$$SV = 130 	ext{ mL} - 60 	ext{ mL} = 70 	ext{ mL}$$

Question 6

Which of the following best describes the function of gap junctions in cardiac muscle cells?

Accepted Answer

They allow electrical signals to pass rapidly between cells, enabling synchronized contraction.

Question 7

Which of the following is a primary effect of sympathetic stimulation on the heart?

Accepted Answer

Increases rate of SA node depolarization

Question 8

A patient with coronary artery disease (CAD) is most likely to experience which of the following?

Accepted Answer

Ischemia due to plaque buildup in coronary arteries

Question 9

Which structure is known as the pacemaker of the heart and initiates the electrical impulse?

Accepted Answer

SA Node

Question 10

During the cardiac cycle, what event occurs during the 0–100 ms interval?

Accepted Answer

Atrial systole

Question 11

Which of the following is a distinguishing feature of contractile cell action potentials compared to pacemaker cell action potentials?

Accepted Answer

Rapid Na$$^+$$ influx causes the spike

Question 12

Which of the following best describes the anatomical location of the heart's apex?

Accepted Answer

Inferior and leftward, pointing toward the 5th intercostal space

Question 13

Which of the following is a key difference between the right and left ventricles?

Accepted Answer

The left ventricle feeds the systemic circuit and generates higher pressure.

Question 14

Which of the following is a chemical marker highly specific for myocardial infarction?

Accepted Answer

Troponin I

Question 15

A patient with heart failure and an ejection fraction (EF) less than 40% is most likely experiencing which subtype?

Accepted Answer

HFrEF (systolic dysfunction)

Question 16

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

Accepted Answer

Contains lubricating fluid to reduce friction during heart movement

Question 17

Which of the following is true regarding the Frank-Starling Law?

Accepted Answer

Increased stretch of cardiac muscle fibers optimizes actin-myosin overlap, increasing contractile force

Question 18

Which of the following is a consequence of ventricular fibrillation (V-Fib)?

Accepted Answer

Zero pumping action, chaotic electrical storm in the ventricles

Question 19

Which of the following is the primary neurotransmitter released by the parasympathetic nervous system to slow heart rate?

Accepted Answer

Acetylcholine

Question 20

Which phase of the cardiac cycle is characterized by AV valves open and passive filling of the ventricles?

Accepted Answer

Passive ventricular filling

The Human Heart: Structure, Function, and Clinical Relevance

Study Guide - Practice Questions