Question

Give reason for following: Arteries have thick walls but no valves

Answer 1

Arteries are the blood vessels which deliver oxygenated blood from the heart pumped by it under pressure. To withstand that pressure, arteries have thick walls.
Arteries deliver blood in a direction which is away from the heart. So there is no need to stop it as if it goes up pressure does the job and if it goes down gravity will. Valves stop blood from going back and make sure that blood flows back to heart, but arteries deliver so no need of it

Answer 2

The walls of the arteries are foundto thicker than that of a vien because the blood that is carried from the heart to the capillarieshas more high pressure. arteries need thicker walls to prevent the arteriesfrom collapsing