A primary prevention for reducing a female patient's risk of developing coronary heart disease is to:

Correct Answer: A

Rationale: Avoiding excessive weight gain during pregnancy reduces long-term cardiovascular risk (e.g., obesity, hypertension). B is secondary prevention, C is for those at risk or post-event, and D treats symptoms, not prevents disease.

Correct Answer: A

Rationale: The aorta (Choice A) is the largest artery in the human body, originating from the left ventricle and distributing oxygenated blood to all systemic circulation. The pulmonary artery (Choice B) carries deoxygenated blood to the lungs but is smaller, the carotid artery (Choice C) supplies the head and neck, and the coronary artery (Choice D) feeds the heart muscle; none rival the aorta’s size or systemic role. Choice A is correct.

Correct Answer: A

Rationale: The sinoatrial (SA) node, the heart’s primary pacemaker, is located in the upper wall of the right atrium near the entrance of the superior vena cava. It initiates the electrical impulses that regulate the heartbeat.

Correct Answer: C

Rationale: Arteries have a thicker tunica media (smooth muscle and elastic fibers) to withstand and regulate high pressure. Veins have a thicker tunica adventitia (connective tissue) but less muscle overall.

Correct Answer: C

Rationale: The blood-brain barrier relies on tightly fused endothelial cells (tight junctions) in brain capillaries, restricting passage of substances and protecting the CNS, aided by astrocytes but defined by this structure.