ATI RN

1. What structures hold up the AV valves and are anchored to the ventricular wall by the papillary muscles?

• A. Chordae tendineae
• B. Papillary muscles
• C. Semilunar valves
• D. Aortic valve

Correct Answer: A

Rationale: The correct answer is A: Chordae tendineae. Chordae tendineae are fibrous cords that connect the AV valves to the papillary muscles, preventing the valves from inverting during ventricular contraction. Papillary muscles (choice B) anchor the chordae tendineae to the ventricular wall but do not hold up the AV valves directly. Semilunar valves (choice C) are located between the ventricles and the major arteries and are not involved in holding up the AV valves. The aortic valve (choice D) is one of the semilunar valves and is not responsible for holding up the AV valves.

2. Which artery supplies the right atrium, right ventricle, a portion of the septum, SA node, AV node, and inferior portion of the left ventricle?

• A. Right coronary artery
• B. Left circumflex artery
• C. Posterior descending artery
• D. Aortic artery

Correct Answer: A

Rationale: The correct answer is the right coronary artery. It supplies essential areas of the heart, including the right atrium, right ventricle, a portion of the septum, SA node, AV node, and the inferior portion of the left ventricle. The left circumflex artery primarily supplies the left atrium and lateral wall of the left ventricle, not the mentioned areas. The posterior descending artery supplies the inferior wall of the left ventricle, not the right side. The aortic artery is a general term and does not specifically refer to an artery that supplies the mentioned areas.

3. What is the term for the ability of cardiac cells to respond to a stimulus by initiating a cardiac impulse?

• A. Excitability
• B. Contractility
• C. Rhythmicity
• D. Conductivity

Correct Answer: A

Rationale: The correct answer is A, Excitability. Excitability is the ability of cardiac cells to respond to a stimulus by initiating a cardiac impulse. Choice B, Contractility, refers to the ability of cardiac muscle to shorten forcibly. Choice C, Rhythmicity, refers to the cardiac muscle's ability to contract rhythmically. Choice D, Conductivity, refers to the ability of the heart's cells to conduct electrical impulses.

4. What is the approximate stroke volume of the heart?

• A. Approximately 60 mL of blood per beat
• B. Approximately 70 mL of blood per beat
• C. Approximately 80 mL of blood per beat
• D. Approximately 90 mL of blood per beat

Correct Answer: B

Rationale: The correct answer is B: Approximately 70 mL of blood per beat. The stroke volume of the heart is typically around 70 mL, indicating the volume of blood ejected from the left ventricle with each contraction. Choices A, C, and D are incorrect as they do not represent the standard approximate stroke volume of the heart, which is around 70 mL per beat.

5. What are the pressure-sensitive structures located in the aortic and carotid bodies called?

• A. Baroreceptors
• B. Chemoreceptors
• C. Nociceptors
• D. Mechanoreceptors

Correct Answer: A

Rationale: Baroreceptors are the correct answer. Baroreceptors are specialized sensory receptors that detect changes in pressure within blood vessels. They are primarily located in the aortic arch and carotid sinuses, where they play a crucial role in regulating blood pressure. Chemoreceptors (Choice B) are receptors that detect chemical changes, not pressure changes. Nociceptors (Choice C) are responsible for detecting painful stimuli. Mechanoreceptors (Choice D) respond to mechanical stimuli such as touch, pressure, and vibration, but they are not specifically located in the aortic and carotid bodies.