Question 1

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

Accepted Answer

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

Question 2

A patient presents with a 'creaking' sound heard through a stethoscope and chest pain. Which condition is most likely, and what is the underlying mechanism?

Accepted Answer

Pericarditis; due to inflammation causing roughened pericardial membranes.

Question 3

Which of the following is TRUE regarding the differences between the right and left ventricles?

Accepted Answer

The left ventricle pumps blood into the systemic circuit and has thicker, round-shaped walls.

Question 4

Which equation correctly represents cardiac output (CO)?

Accepted Answer

$$CO = HR 	imes SV$$

Question 5

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

$$SV = 130\,mL - 60\,mL = 70\,mL$$

Question 6

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

Accepted Answer

The absolute refractory period in cardiac muscle is almost as long as the contraction itself.

Question 7

Which structure is responsible for setting the basic rhythm of the heart and why?

Accepted Answer

Sinoatrial (SA) node; because it depolarizes faster than any other cardiac myocyte.

Question 8

Which of the following is a direct effect of increased sympathetic nervous system activity on the heart?

Accepted Answer

Increased heart rate and increased contractility.

Question 9

A patient with persistent high blood pressure is at risk for which of the following cardiac changes?

Accepted Answer

Increased afterload, leading to ventricular hypertrophy and eventual heart failure.

Question 10

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

Accepted Answer

The greater the preload (stretch), the greater the force of contraction and stroke volume.

Question 11

Which of the following is a consequence of a stenotic heart valve?

Accepted Answer

Blood flow through the valve is restricted, causing a high-pitched or clicking sound.

Question 12

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

Accepted Answer

It pumps blood to the entire body through the systemic circuit, which has higher resistance.

Question 13

Which of the following is the correct sequence of excitation in the intrinsic conduction system of the heart?

Accepted Answer

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

Question 14

A patient has a heart rate of 80 beats/min and a stroke volume of 65 mL/beat. What is their cardiac output?

Accepted Answer

$$CO = 80 	imes 65 = 5200\,mL/min$$

Question 15

Which of the following is a direct result of hyperkalemia (high blood K+)?

Accepted Answer

Heart block and possible cardiac arrest due to altered resting membrane potential.

Question 16

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

Accepted Answer

They anchor the AV valve cusps to the papillary muscles, preventing valve prolapse.

Question 17

Which of the following is a feature unique to cardiac muscle cells compared to skeletal muscle cells?

Accepted Answer

Presence of intercalated discs with gap junctions and desmosomes.

Question 18

Which of the following would most likely result from a total heart block?

Accepted Answer

Ventricles beat at their own intrinsic rate, which is too slow to maintain adequate circulation.

Question 19

Which of the following best describes the effect of the Bainbridge (atrial) reflex?

Accepted Answer

It increases heart rate in response to increased venous return and atrial filling.

The Cardiovascular System: The Heart – Structure, Function, and Regulation

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