Q: Calculate the cardiac output (CO) for a patient with a heart rate (HR) of 80 beats/min and a stroke volume (SV) of 70 mL/beat. Use the formula $$CO = HR \times SV.$$

$$CO = 80 \times 70 = 5600\ \text{mL/min}$$

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 tissues during contraction.

Question 2

A patient presents with a 'creaking' sound heard with a stethoscope and chest pain. Which condition is most likely, and what is a possible severe complication?

Accepted Answer

Pericarditis; cardiac tamponade

Question 3

Which structure is the remnant of the fetal foramen ovale in the adult heart?

Accepted Answer

Fossa ovalis

Question 4

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

Accepted Answer

AV valves are closed; SL valves are open

Question 5

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

Accepted Answer

It pumps blood with greater pressure to the systemic circuit.

Question 6

A patient with a defective mitral valve is most likely to experience which of the following?

Accepted Answer

Backflow of blood into the left atrium during ventricular contraction

Question 7

Which of the following is the correct sequence of electrical excitation in the heart?

Accepted Answer

Sinoatrial node → Atrioventricular node → Atrioventricular bundle → Bundle branches → Purkinje fibers

Question 8

Which of the following best describes the QRS complex on an electrocardiogram (ECG)?

Accepted Answer

Ventricular depolarization and atrial repolarization

Question 9

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

Accepted Answer

Congestive heart failure

Question 10

Calculate the cardiac output (CO) for a patient with a heart rate (HR) of 80 beats/min and a stroke volume (SV) of 70 mL/beat. Use the formula $$CO = HR 	imes SV.$$

Accepted Answer

$$CO = 80 	imes 70 = 5600\ 	ext{mL/min}$$

Question 11

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

Accepted Answer

Cardiac arrest due to altered electrical activity

Question 12

A newborn is diagnosed with a patent ductus arteriosus. What is the physiological consequence of this defect?

Accepted Answer

Mixing of oxygen-poor and oxygen-rich blood between the pulmonary trunk and aorta

Question 13

Which of the following best explains why the heart cannot undergo tetanic contractions?

Accepted Answer

It has a long absolute refractory period, preventing summation of contractions.

Question 14

Which of the following is a function of the fibrous skeleton of the heart?

Accepted Answer

It anchors cardiac muscle fibers and limits the spread of action potentials.

Question 15

A patient with left-sided heart failure is most likely to develop which of the following complications?

Accepted Answer

Pulmonary congestion and fluid accumulation in the lungs

Question 16

Which of the following statements about cardiac muscle is TRUE?

Accepted Answer

Cardiac muscle cells are branched, have a single nucleus, and are rich in mitochondria.

Question 17

Which of the following best describes the effect of the parasympathetic nervous system on the heart?

Accepted Answer

It decreases heart rate by inhibiting the SA node.

Question 18

A patient is found to have a heart murmur due to valvular stenosis. What is the most likely effect on the heart?

Accepted Answer

The heart must exert more force to pump blood through the narrowed valve.

Question 19

Which of the following is a direct effect of ischemia on cardiac muscle cells?

Accepted Answer

Increased lactic acid production, leading to high H+ concentration and possible arrhythmias

Question 20

Which of the following congenital heart defects results in the mixing of oxygen-poor and oxygen-rich blood due to a failure of a fetal structure to close?

Accepted Answer

Patent foramen ovale

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

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