ANATOMY

Detailed explanation-1: -The veins constrict, reducing their capacity to hold blood in less important parts of the body. The arterioles constrict, increasing their resistance to blood flow.

Detailed explanation-2: -In general, blood pressure decreases from arteries to veins, and this is because of the pressure overcoming the resistance of the vessels. The greater the change in resistance at any point in the vasculature, the greater the loss of pressure at that point.

Detailed explanation-3: -Explanation: In the general circulation, the highest blood pressure is found in the aorta and the lowest blood pressure is in the vena cava.

Detailed explanation-4: -Veins carry blood under low pressure from the capillaries and return the blood to the heart. The vein walls have thinner muscular walls than arteries and have a wider internal diameter. Veins contain valves to prevent the backflow of low-pressure blood.