ATI RN
Questions About the Cardiovascular System Questions
Question 1 of 5
The first branch of the human aorta is:
Correct Answer: B
Rationale: The first branches of the aorta are the coronary arteries (B), arising from the aortic root to supply the heart. Brachiocephalic (A), carotid (C), and subclavian (D) branch from the aortic arch.
Question 2 of 5
Absolute refractory period in heart:
Correct Answer: D
Rationale: the absolute refractory period (~0.25-0.3 s) lasts through systole (A), is longer than skeletal muscle (B, ~0.002 s), prevents restimulation (C), and matches the action potential (D).
Question 3 of 5
Distribution of blood flow is mainly regulated by the:
Correct Answer: B
Rationale: Arterioles (B) regulate flow via resistance (smooth muscle). Arteries (A) conduct, capillaries (C) exchange, venules (D) collect.
Question 4 of 5
What type of tissue comprises the valves of the heart?
Correct Answer: A
Rationale: Heart valves are made of dense connective tissue (A), providing strength and flexibility. Areolar tissue (B) is loose, hyaline cartilage (C) is in joints, and cardiac muscle (D) forms the heart wall.
Question 5 of 5
Which of the following would lead to a decreased heart rate?
Correct Answer: C
Rationale: High plasma potassium (C) (hyperkalemia) slows heart rate by depolarizing cells, reducing excitability. Norepinephrine (A), thyroid hormone (B), and calcium (D) increase rate.