Question

The blood pressure in humans is greater at the feet than the brain because-
A) Of gravitational force
B) Weight of man is concentrated at the feet
C) Of height of blood column
D) Concentration of blood is more at feet

Answer 1

The blood is directly proportional to the height of the blood column in the individual, so as to answer this correctly, we need to understand the basics of circulation.

Complete answer:
In humans, the blood circulatory system carries out circulation in 2 manners, pulmonary circulation and systemic circulation. The pulmonary circulation is responsible for exchange of gases between blood and the environment taking in the oxygen and releasing out carbon dioxide. The systemic circulation provides oxygen to the organs, tissues and cells and brings back carbon dioxide from them to the lungs. It consists of a heart and numerous blood vessels running through the entire body. Blood is carried away from the heart through arteries while the veins carry the blood back to the heart. The system of blood vessels looks similar to a tree: The main artery (aorta) resembles the trunk, large arteries as branches, which further lead to much smaller vessels. The smallest arteries finally end in a network of extremely fine vessels known as the capillaries which together form capillary networks. The heart pumps the blood through the system, blood is forced into the blood vessel with each heartbeat. The diameter and elasticity of the walls of the vessels affect blood pressure. The height of the blood column inside a body also affects the blood pressure, the pressure is higher at higher columns.

Thus, the correct answer is option ‘C’ i.e, of the height of the blood column.

Note: The height is directly proportional to the pressure in vessels due to which the height of the blood column in the body influences the blood pressure in vessels. At the feet, the height of the blood column is greater than it is at the brain. Therefore, the blood pressure at the feet is more than it is at the brain.