Question

How would you compare the structures and functions of arteries, capillaries and veins?

Answer 1

Arteries, Veins and the capillaries are the blood vessels that help in the transport of blood all through the body. This helps in supplying water, oxygen and nutrients to the various cells present in the body.

Complete answer:
-The oxygenated blood is pumped through the left ventricle of the heart into the aorta. The blood then passes through the majority of the arteries and microscopic arterioles. Further branching of these arterioles into the capillary networks takes place thus supplying the tissues with nutrients and oxygen. The arterial walls are thicker as compared to the walls of the veins having surplus elastic tissue as well as smooth muscles which aids in the dilation of the arteries when the blood is pumped through them.

-After transporting the nutrients and oxygen to various tissues present in the body, blood is carried back through the veins from where it is transported back to the heart via vena cava. The walls of veins are comparatively less elastic and thinner than the arterial walls therefore blood is carried with low pressure. Moreover, valves are also present to prevent the backflow of the blood in the veins.

-From the arterioles tiny vessels known as the capillaries branch out thereby forming a network around the cells of the body. Within the lungs, absorption of oxygen in the blood takes place from the air inhaled while carbon dioxide is released with exhalation. The capillaries diffuse oxygen and other nutrients present in the blood into various body tissues. Also, other waste products as well as the carbon dioxide from the cells of the body is absorbed through these capillaries thereby flowing the deoxygenated blood towards the veins.

Note: With the movement blood across the circulatory system, a pressure is exerted on the walls of the blood vessels present in the heart. This pressure is known as the blood pressure.