ATI RN

1. Which heart chamber ejects blood into the lungs via the pulmonary artery?

• A. Right atrium
• B. Left atrium
• C. Right ventricle
• D. Left ventricle

Correct Answer: C

Rationale: The correct answer is C, the right ventricle. The right ventricle is responsible for pumping deoxygenated blood into the lungs through the pulmonary artery for oxygenation. Choices A, B, and D are incorrect because the right atrium receives deoxygenated blood from the body, the left atrium receives oxygenated blood from the lungs, and the left ventricle pumps oxygenated blood to the body, respectively.

2. This is a branch of the left coronary arteries which supplies the LEFT ATRIUM, posterior lateral surface of the left ventricle.

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

Correct Answer: B

Rationale: The correct answer is B, Left circumflex artery. The circumflex artery is a branch of the left coronary artery that supplies blood to the left atrium and the lateral wall of the left ventricle. Choice A, the Right coronary artery, does not supply the mentioned areas. Choice C, the Left anterior descending artery, supplies the anterior wall of the left ventricle. Choice D, the Posterior descending artery, is a branch of the right coronary artery and supplies the inferior wall of the left ventricle and the posterior septum.

3. After the AV node, the electrical impulse is then transmitted into the _________, and into the _________.

• A. Purkinje fibers, ventricles
• B. Atria, ventricles
• C. Bundle of His, Purkinje fibers
• D. Ventricles, Purkinje fibers

Correct Answer: C

Rationale: The correct answer is C. After the AV node, the electrical impulse is transmitted to the Bundle of His and then to the Purkinje fibers. This sequence is crucial for the coordinated contraction of the ventricles. Choice A (Purkinje fibers, ventricles) is incorrect because the Purkinje fibers come after the Bundle of His in the sequence of electrical conduction. Choice B (Atria, ventricles) is incorrect because the impulse does not go back to the atria after passing through the AV node. Choice D (Ventricles, Purkinje fibers) is incorrect because the impulse first reaches the Bundle of His before spreading to the Purkinje fibers.

4. What is the average cardiac output?

• A. Approximately 4 to 6 L per minute
• B. Approximately 4 to 8 L per minute
• C. Approximately 5 to 8 L per minute
• D. Approximately 3 to 7 L per minute

Correct Answer: B

Rationale: The correct answer is B: Approximately 4 to 8 L per minute. Cardiac output is defined as the volume of blood the heart pumps per minute, typically ranging between 4 to 8 liters. Choices A, C, and D provide ranges that are either too narrow or outside the standard average values for cardiac output, making them incorrect.

5. Which term conceptualizes that the greater the myocardial fiber stretch, within physiologic limits, the more forceful the ventricular contraction, thereby increasing stroke volume?

• A. Frank-Starling’s Law
• B. Automaticity
• C. Contractility
• D. Excitability

Correct Answer: A

Rationale: The correct answer is A, Frank-Starling’s Law. This law explains that within physiologic limits, the greater the stretch of myocardial fibers, the more forceful the ventricular contraction, leading to an increased stroke volume. Choice B, Automaticity, refers to the ability of cardiac cells to spontaneously generate electrical impulses. Choice C, Contractility, represents the intrinsic ability of the heart muscle to contract. Choice D, Excitability, refers to the ability of cardiac cells to respond to electrical stimuli.