PATHOLOGY

Detailed explanation-1: -One cell thick vessels are the blood vessels that join arteries and veins are the tiniest and most abundant blood vessels, called capillaries. They primarily serve the purpose of exchanging materials between the blood and tissue cells.

Detailed explanation-2: -Capillaries contain two layers of cells: Endothelial cells are inside the capillary. They control the flow of fluid, nutrients and gases.

Detailed explanation-3: -Capillaries: These tiny blood vessels have thin walls. Oxygen and nutrients from the blood can move through the walls and get into organs and tissues.