Which anatomical regions of the heart are directly served by the right coronary artery?

A. Activation of chemoreceptors:
Chemoreceptors respond to oxygen, carbon dioxide, and pH levels in the blood, affecting ventilation rather than fluid retention.

B. Activation of the renin-angiotensin-aldosterone system:
RAAS increases blood pressure by promoting sodium and water reabsorption in the kidneys, increasing blood volume, and by causing vasoconstriction, increasing systemic vascular resistance. This is a major mechanism in long-term blood pressure regulation.

C. Baroreceptor reflex:
Baroreceptors detect acute changes in blood pressure and adjust heart rate and vascular tone but do not directly control sodium and water retention.

D. Release of antidiuretic hormone:
ADH increases water reabsorption in the kidneys, but its effect on sodium retention is indirect and less significant compared to RAAS.

A. Posterior wall of the left ventricle:
The posterior wall of the left ventricle is usually supplied by the circumflex artery or posterior descending artery, depending on coronary dominance.

B. Right atrium and portions of the right ventricle:
The RCA primarily supplies the right atrium, right ventricle, SA node, and AV node, supporting right-sided contraction and conduction. Occlusion can lead to arrhythmias and right heart dysfunction.

C. Left ventricle and left atrium:
These structures are mainly supplied by the left coronary artery (LAD and circumflex branches).

D. Interventricular septum and apex of the heart:
The LAD supplies the anterior interventricular septum and apex, not the RCA.