Capillaries are extremely small blood vessels responsible for the delivery of essential nutrients directly to tissues throughout the body. They also help the body circulate blood and remove waste from its organs.
Capillaries contain small holes in their structure that allow oxygen and other nutrients to pass through into organs and tissues. Specific types of capillaries are determined by their functions, which affects their number and placement in the body. Capillaries are the smallest types of blood vessels in the body and operate as a network of many blood vessels woven together. They are most numerous in areas of the body that require a higher amount of oxygen and nutrient exchange.