Which of the following heart valves separates the right atrium from the right ventricle?

A. Cardiac index is a measurement of cardiac output adjusted for body surface area. It provides a more individualized assessment of heart function, but it does not describe the amount of blood ejected during each contraction.

B. Cardiac output refers to the total amount of blood the heart pumps in one minute, which is the product of stroke volume and heart rate. However, it describes the overall volume pumped by the heart, not the blood ejected per contraction.

C. Stroke volume is the term used to describe the amount of blood ejected from the left ventricle during each contraction. It is a key indicator of cardiac function.

D. Ejection fraction is the percentage of blood in the left ventricle that is pumped out with each contraction, representing the efficiency of the heart. It is related to stroke volume but is not the same as the volume ejected per contraction.

A. The peripheral nervous system is responsible for transmitting signals between the central nervous system and the rest of the body, but it does not directly govern the increase in peristalsis.

B. The central nervous system (CNS) processes information and coordinates responses but does not directly control the movement of the digestive system. The autonomic nervous system, which includes the parasympathetic and sympathetic divisions, controls peristalsis.

C. The parasympathetic nervous system is responsible for "rest-and-digest" activities. It stimulates peristalsis to promote digestion and the movement of food through the gastrointestinal tract, leading to an increase in peristalsis.

D. The sympathetic nervous system is involved in the "fight-or-flight" response, which inhibits digestive processes, including peristalsis, as the body prioritizes other functions.