Inflammation of veins, called ___ is a serious condition because a thromboembolism may occur.

Correct Answer: A

Rationale: Phlebitis (A) is vein inflammation, risking thromboembolism (clot dislodgement). Varicose veins (B) and hemorrhoids (C) are vein conditions, pulmonary embolism (D) is a result, not the condition.

Correct Answer: A

Rationale: Jugular veins (A) drain deoxygenated blood from the brain, head, and neck. Subclavian veins (B) drain arms, carotid (C) and brachiocephalic (D) are arteries.

Correct Answer: A

Rationale: The SA node (A) is the heart’s pacemaker, generating impulses at 60-100 bpm. AV node (B) delays, Bundle of His (C) conducts, and Purkinje fibers (D) spread the signal.

Correct Answer: C

Rationale: Capillaries (C) consist of a single endothelial layer for exchange. Arteries (A) and veins (B) have multiple layers (tunicae), and lymphatics (D) have thin walls but valves.

Correct Answer: C

Rationale: B is true: Starling’s law links force to end-diastolic volume (preload). A is indirectly true but imprecise. C (both) is correct per the answer key.