Q: If a patient’s end diastolic volume (EDV) is 130 mL and end systolic volume (ESV) is 60 mL, what is the stroke volume (SV)?

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

Question 1

Which of the following best describes the function of the chordae tendineae in the heart?

Accepted Answer

They anchor the cusps of the atrioventricular (AV) valves to the papillary muscles, preventing valve prolapse during ventricular contraction.

Question 2

A patient presents with a heart murmur characterized by a 'swishing' sound immediately after the first heart sound (S1). Which valve is most likely incompetent?

Accepted Answer

Atrioventricular (AV) valve

Question 3

Which of the following is a key structural difference between cardiac and skeletal muscle, as shown in the provided electron micrograph?

Accepted Answer

Cardiac muscle cells are branched and interconnected by intercalated discs, while skeletal muscle cells are long and cylindrical.

Question 4

During which phase of the cardiac cycle are all heart valves closed and the ventricles are neither filling nor ejecting blood?

Accepted Answer

Isovolumetric contraction

Question 5

Which of the following best explains why the left ventricular wall is thicker than the right ventricular wall?

Accepted Answer

The left ventricle must generate higher pressure to pump blood through the systemic circuit, which has greater resistance than the pulmonary circuit.

Question 6

A patient with persistent high blood pressure is at risk for which of the following changes in cardiac output, and why?

Accepted Answer

Increased afterload leads to increased end systolic volume (ESV) and reduced stroke volume (SV), decreasing cardiac output (CO).

Question 7

Which of the following best describes the sequence of electrical excitation in the heart?

Accepted Answer

Sinoatrial (SA) node → Atrioventricular (AV) node → AV bundle (Bundle of His) → Right and left bundle branches → Purkinje fibers

Question 8

A patient’s ECG shows a prolonged Q-T interval. What is the clinical significance of this finding?

Accepted Answer

It indicates a repolarization abnormality that increases the risk of ventricular arrhythmias.

Question 9

Which of the following equations correctly represents the relationship between cardiac output, heart rate, and stroke volume?

Accepted Answer

$$CO = HR 	imes SV$$

Question 10

If a patient’s end diastolic volume (EDV) is 130 mL and end systolic volume (ESV) is 60 mL, what is the stroke volume (SV)?

Accepted Answer

$$SV = EDV - ESV = 130\ 	ext{mL} - 60\ 	ext{mL} = 70\ 	ext{mL}$$

Question 11

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

Accepted Answer

The greater the stretch of cardiac muscle cells before contraction (preload), the greater the force of contraction.

Question 12

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

Accepted Answer

Epinephrine

Question 13

A patient with a defective SA node develops a junctional rhythm. What is the expected heart rate range?

Accepted Answer

40–60 beats per minute

Question 14

Which of the following best describes the effect of acetylcholine on the heart?

Accepted Answer

It hyperpolarizes pacemaker cells by opening K+ channels, slowing heart rate.

Question 15

Which of the following congenital heart defects is characterized by a narrowed aorta, increasing the workload of the left ventricle?

Accepted Answer

Coarctation of the aorta

Question 16

A patient with congestive heart failure (CHF) due to left-sided failure is most likely to experience which of the following symptoms?

Accepted Answer

Pulmonary congestion (blood backs up in the lungs)

Question 17

Which of the following best explains why tetanic contractions cannot occur in cardiac muscle?

Accepted Answer

Cardiac muscle has a long refractory period, preventing sustained contractions.

Question 18

Which of the following is the correct order of the waves seen on a normal ECG?

Accepted Answer

P wave, QRS complex, T wave

Question 19

A patient with hyperkalemia is at risk for which of the following cardiac complications?

Accepted Answer

Heart block and cardiac arrest

Anatomy and Physiology of the Heart: Structure, Function, and Clinical Aspects

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