Q: A patient has a heart rate of 80 beats per minute and a stroke volume of 70 mL per beat. What is the cardiac output ($$CO) in $$liters per minute? Use the formula $$CO = HR \times SV.$$

$$CO = 80 \times 70 = 5600 mL/$$min $$= 5.6 L/$$min

Question 1

Which of the following best describes the anatomical location of the heart within the thorax?

Accepted Answer

It is located in the mediastinum, between the lungs, posterior to the sternum, and superior to the diaphragm.

Question 2

Which layer of the heart wall is primarily responsible for the contractile force that pumps blood throughout the body?

Accepted Answer

Myocardium

Question 3

A patient is diagnosed with a blockage in the left anterior descending artery. Which region of the heart is most at risk for ischemia?

Accepted Answer

Anterior wall of the left ventricle and interventricular septum

Question 4

Which of the following correctly matches a heart valve with its function?

Accepted Answer

Tricuspid valve: prevents backflow of blood from the right ventricle to the right atrium during ventricular contraction

Question 5

During the cardiac cycle, which event is directly responsible for the first heart sound ($$S_1$$)?

Accepted Answer

Closure of the atrioventricular (AV) valves

Question 6

Which of the following best describes the pathway of blood flow through the heart, starting from the vena cava?

Accepted Answer

Vena cava $$\rightarrow$$ right atrium $$\rightarrow$$ right ventricle $$\rightarrow$$ pulmonary trunk $$\rightarrow$$ lungs $$\rightarrow$$ left atrium $$\rightarrow$$ left ventricle $$\rightarrow$$ aorta

Question 7

Which of the following statements about the conduction system of the heart is correct?

Accepted Answer

The sinoatrial (SA) node initiates the electrical impulse that spreads through the atria, causing atrial contraction.

Question 8

A patient has a heart rate of 80 beats per minute and a stroke volume of 70 mL per beat. What is the cardiac output ($$CO) in $$liters per minute? Use the formula $$CO = HR 	imes SV.$$

Accepted Answer

$$CO = 80 	imes 70 = 5600 mL/$$min $$= 5.6 L/$$min

Question 9

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

Accepted Answer

The greater the stretch of the ventricular muscle fibers during filling, the greater the force of contraction during systole.

Question 10

Which of the following is a direct effect of increased parasympathetic stimulation on the heart?

Accepted Answer

Decreased heart rate

Question 11

A patient presents with a heart murmur best heard at the left fifth intercostal space, midclavicular line. Which valve is most likely affected?

Accepted Answer

Mitral (bicuspid) valve

Question 12

Which of the following best describes the function of intercalated discs in cardiac muscle tissue?

Accepted Answer

They allow rapid transmission of electrical impulses and mechanical connection between cardiac muscle cells.

Question 13

Which of the following events occurs during ventricular systole?

Accepted Answer

The semilunar valves open and blood is ejected into the aorta and pulmonary trunk.

Question 14

Which of the following best describes the role of the autonomic nervous system in regulating cardiac output?

Accepted Answer

Sympathetic stimulation increases heart rate and contractility, while parasympathetic stimulation decreases heart rate.

Question 15

A patient has a mutation affecting the function of the sarcoplasmic reticulum in cardiac muscle cells. Which process would be most directly impaired?

Accepted Answer

Release and reuptake of calcium ions during excitation-contraction coupling

Question 16

Which of the following best describes the function of the papillary muscles in the heart?

Accepted Answer

They contract to prevent prolapse of the atrioventricular valves during ventricular contraction.

Question 17

Which of the following is a correct sequence of events in excitation-contraction coupling in cardiac muscle?

Accepted Answer

Action potential $$\rightarrow$$ calcium influx $$\rightarrow$$ calcium release from sarcoplasmic reticulum $$\rightarrow$$ contraction

Question 18

Which of the following would most likely result from a blockage in the right coronary artery?

Accepted Answer

Ischemia of the right atrium and portions of the right ventricle

Question 19

A 60-year-old patient has a resting heart rate of 55 beats per minute and a stroke volume of 80 mL per beat. Calculate the cardiac output ($$CO) $$using $$CO = HR 	imes SV.$$

Accepted Answer

$$CO = 55 	imes 80 = 4400 mL/$$min $$= 4.4 L/$$min

Question 20

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 circulation.

Anatomy & Physiology: The Heart – Structure, Function, and Regulation

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