Question

5. Explain how different regions of the cardiovascular system correspond to the following "reservoirs" for pressure resistance, and volume. Region of cardiovascular system How it acts as a "reservoir Pressure Reservoir anteruo Resistance Reservoir anter Volume Reservoir | า-uns

Answer 1

	Region of cardiovascular system	How it acts as a "Reservoir”
Pressure reservoir	Arteries	Arteries walls have a unique property that is elasticity and these elastic walls of Arteries are responsible to behave as a pressure reservoir. When the ventricles pour out blood from the heart the elastic arteries expands. The reason it happens is that the more blood flows into the arteries than the blood drained out in smaller arterioles and it is downstream. And even at the time of ventricular relaxation the blood is continue to drive forward due to electric recoil of the arteries.
Resistance reservoir	Arterioles	Arterioles acts as the primary site for the vascular resistance because their lumen size is about 30 micrometers/less in diameter and their muscular walls is generally 1-2 layers of smooth muscles. The primary mechanisms of arterioles for the distribution of blood flow are vasoconstriction and vasodilation. Arterioles are censorious in resisting the blood flow and causes considerable decrease in the blood pressure. Hence arterioles are called as Resistance reservoir.
Volume reservoir	Veins	The volume of the blood in the vein stays under low pressure. Due to this unstressed volume the veins contain 60% blood volume of body and hence veins acts as volume reservoir.