Blood flow volume changes in the body are primarily influenced by which two factors?

Blood flow volume changes in the body are primarily influenced by cardiac function and peripheral resistance. Cardiac function, represented largely by the heart's ability to pump blood effectively, directly determines the stroke volume—the volume of blood ejected from the heart with each beat. This, in turn, significantly influences overall blood flow throughout the body.

Peripheral resistance refers to the resistance to blood flow provided by the smaller blood vessels (arterioles and capillaries). Factors such as vessel diameter and the degree of vasoconstriction or vasodilation directly affect peripheral resistance. When resistance increases, blood flow decreases, and vice versa. Thus, cardiac function paired with peripheral resistance gives a comprehensive picture of how blood flow volume can change throughout different physiological conditions or responses, making this combination essential for understanding hemodynamics.

The other options focus on aspects that are important but do not encompass the two primary factors influencing blood flow volume changes under normal physiological circumstances.