An increase in total plasma volume results from the:

Correct Answer: D

Rationale: Antidiuretic hormone and aldosterone mechanisms both contribute to increased plasma volume.

Correct Answer: C

Rationale: The sinoatrial node (SA node) is the pacemaker located in the right atrial wall just inferior to the entrance of the superior vena cava. The SA node generates impulses which travel across the atria (followed by atrial systole) and then pause (0.1s) at the atrioventricular node (AV node, sited at the superior part of the inter-ventricular septum) and then to the bundle of His located between the ventricles, splitting into right and left branches down the inter-ventricular septum towards the heart apex, and out to the Purkinje fibres which turn superiorly into the ventricular walls (followed by ventricular systole).

Correct Answer: B

Rationale: The common carotid artery typically bifurcates into internal and external carotid arteries at the C3-C4 level.

Correct Answer: C

Rationale: The AV bundle (AV node) has the slowest conduction to delay the impulse, allowing atrial contraction before ventricular.

Correct Answer: A

Rationale: Right heart failure increases right atrial pressure due to backflow from the failing right ventricle.