AP BIOLOGY

Detailed explanation-1: -(d) They have thick elastic walls without valves inside, blood flows under high pressure and carries blood away from the heart to different parts of the body. Q. Assertion: Arteries have thick elastic walls. Reason: Blood flow in arteries is rapid and at high pressure.

Detailed explanation-2: -Arteries: These strong, muscular blood vessels carry oxygen-rich blood from your heart to your body. They handle a large amount of force and pressure from your blood flow but don’t carry a large volume of blood.

Detailed explanation-3: -Blood flows in arteries in spurts and under pressure because they carry (oxygenated) blood which is pumped out from the heart (Ventricle) with force. This pressure helps the blood to reach every part of the body.

Detailed explanation-4: -If you increase pressure in the arteries (afterload), and cardiac function does not compensate, blood flow will actually decrease. In the venous system, the opposite relationship is true. Increased pressure in the veins does not decrease flow as it does in arteries, but actually increases flow.