Atrial systole causes blood to:

Correct Answer: C

Rationale: Atrial systole pushes blood from the atria into the ventricles through the cuspid (atrioventricular) valves (tricuspid and mitral), not out of the heart or through semilunar valves.

Correct Answer: D

Rationale: The apex of the heart is formed by the left ventricle, located at the bottom left of the heart, pointing inferolaterally.

Correct Answer: C

Rationale: Sinusoidal capillaries, with large gaps, are found in red bone marrow, liver, and spleen, not typically in pulmonary capillaries.

Correct Answer: D

Rationale: Sympathetic stimulation releases norepinephrine, increasing ventricular contractility.

Correct Answer: D

Rationale: Dehydration decreases ANP (which promotes fluid loss), while increasing vasopressin, angiotensin II, and norepinephrine.