Question

These vessels carry blood under high pressure out to the body tissues.

a) veins

b) arteries

c) capillaries

d) lymph vessels

Answer 1

Ans. Correct option- B. Arteries. The left ventricle pumps blood with relatively greater pressure to expel the oxygenated blood into the systemic circulation. The blood vessels carrying this oxygenated blood from heart to different body parts (organs, tissues, etc.) are called arteries. Since the left ventricle exert greater pressure to expel oxygenated blood, the blood pressure in arteries is highest than other vessel of the circulatory system.

# Vein generally carry blood from systemic circulation to the heart. The flow of blood through veins to the right atrium is due to relaxation (expansion) of right atrium – the expansion creates partial negative pressure to draw blood in it. So, the pressure in veins is relatively much lower than those in arteries.

# Arteries further divide into one-cell thick layered capillaries. The capillaries transport blood to tissues. The capillaries are the transition point of arteries into vein where actual gas exchange between the blood and tissues occur. Because of being only one-cell thick, these vessels can’t withstand higher pressure (neither they need to as gaseous exchange takes place by simple diffusion). That is, pressure in capillaries in generally the least.

# The lymphatic circulation facilitates the transport of lymph to the heart through lymphatic ducts. These vessels do NOT carry blood.