Question : Give reasons for the following :(i)The muscular walls of ventricles are thicker than the walls ofatria.(ii)Arteries have thick elastic walls.(iii)Veins have valves .

Question : Give reasons for the following :(i)The muscular walls of ve

1.	Question : Give reasons for the following :(i)The muscular walls of ventricles are thicker than the walls ofatria.(ii)Arteries have thick elastic walls.(iii)Veins have valves .
Answer» Solution :(i) The walls of VENTRICLES are thick and muscular as compared to the walls of atria as they are required to pump blood to VARIOUS organs. Right VENTRICLE sends deoxygenated blood to lungs throughpulmonary artery whereas left ventricle sends oxygenated blood to all PARTS of the body through aorta. (ii) Since the blood emerges from the heart under high pressure , the arteries have thick, elastic walls. (iii)Veins have valves to ENSURE that the blood does not flow backward when the atria or ventricles contract.