Question

The heart usually pumps blood with greater force in the old people than the young because :
A. The oxygen content per unit volume of the blood decreases
B. The elasticity of the arteries decreases
C. The elasticity of the arteries increases
D. The nutrient content per unit of blood decreases

Answer 1

Hint: Oxygen rich blood is transported from lung to heart from where it is transported to the body and oxygen-deficient blood is transported from the body to the heart from where it is transported to lungs for oxygenation. Oxygen-rich blood is transported through arteries and oxygen-deficient blood is transported through veins. Blood pressure is the force exerted by blood per unit area of the blood vessels.

Complete answer: Blood having no oxygen is transported from the body through inferior and superior vena cava to the right atrium of the heart. Then blood travels from the right atrium to the ventricle as the atrium contracts and the tricuspid valve opens. Ventricles fill fully and the tricuspid valve closes. Ventricles contract and blood enters the pulmonary artery and is transported to the lungs for oxygenation. From the lungs, the oxygen-rich blood is transported to the left atrium of the heart through the pulmonary vein. Blood is then transported from the left atrium to the left ventricle as the atrium contracts and the mitral valve opens. Ventricles fully fill and the mitral valve closes. Blood now enters the aorta through the aortic valve as ventricles contract. Through the aorta, oxygen-rich blood is transported to the body. As the person grows old the elasticity of arteries decreases and resistance increases. These arteries are not able to relax rapidly when blood is pumped by the heart because of which greater force is exerted by the heart. An increase in blood pressure is also because of this reason.
Hence, the correct answer is Option B

Note: Blood vessels are responsible for blood flow in the human body .Oxygen is transported from the heart to the body through arteries and with age elasticity of arteries decreases which increases the force exerted by heart and also increases blood pressure in old age.