GENERAL HISTOLOGY

Detailed explanation-1: -The aorta branches into arteries, which eventually branch into smaller arterioles. Arterioles carry blood and oxygen into the smallest blood vessels, the capillaries. Capillaries are so small they can only be seen under a microscope. The walls of the capillaries are permeable to oxygen and carbon dioxide.

Detailed explanation-2: -To return blood to the heart, there is a series of venules, veins, and muscular veins. Venules have much larger lumina and thinner walls than corresponding arterioles. Similarly, the veins are distinguishable from arteries and arterioles, because their walls are much thinner, compared to the diameter of their lumen.

Detailed explanation-3: -Arterioles: Arteries branch into smaller vessels called arterioles. Both arteries and arterioles are very flexible. They get bigger or smaller to help maintain your body’s blood pressure. Capillaries: These tiny blood vessels have thin walls.

Detailed explanation-4: -Capillaries, the smallest and most numerous of the blood vessels, form the connection between the vessels that carry blood away from the heart (arteries) and the vessels that return blood to the heart (veins). The primary function of capillaries is the exchange of materials between the blood and tissue cells.