Question

How does the volume of circulating blood affect blood pressure?

Answer 1

Blood circulation:

1. In our body blood flows in the blood vessels.
2. Blood vessels are hollow tubes and their wall is made up of multiple layers of tissue.
3. The middle layer is made up of muscular tissue that can change the diameter of vessels.
4. When the blood vessels are constricted, the flowing blood to has high pressure, and when the vessels are dilated, the flowing blood has lower pressure.
5. When circulating blood volume is less, blood flow in the kidney is also decreased.
6. In this case, juxtaglomerular cells of the kidney secrete Renin. Renin hormone converts the liver enzyme angiotensinogen into angiotensin-I.
7. Angiotensin-I is then converted into angiotensin-II in the lungs.
8. This hormone act as a vasoconstrictor which causes the blood vessels to become constricted and increases blood pressure.
9. It also leads to the synthesis of Aldosterone, which is a major regulator of blood pressure and blood volume.