Blood is circulated throughout our body for proper functioning, and this process is done by tube-like structured known as blood vessels. These channels carry blood in the form of a closed loop or a circuit that starts and ends at the heart. A human body consists of about 60,000 miles of blood vessels. They are about the size of a nickel (2 cm wide), even less, i.e., 2-12 micrometers for human hair.
Types of Blood Vessels & Their Functions
1. Arteries: the vessels that carry the oxygenated blood from the heart and are considerably strong and muscular. Handling a large amount of stress and pressure. About 10-15% of the blood is in the arteries at any time.
2. Veins: the blood vessels that carry large volumes of deoxygenated blood back to the heart and do not have to handle highly pressurized blood. The blood flow in veins is controlled by the valves that keep your blood flowing in one direction. About 75% of the blood is found in veins.
3. Capillaries: smallest blood vessels that connect arteries and veins and let oxygen and nutrients from the blood move in and out to the tissue cells.
How do they assist the blood flow?
Veins bring the deoxygenated blood back to the heart, carried to the lungs via pulmonary arteries, where the blood collects oxygen. Pulmonary veins are the carriers of the oxygen-rich blood towards the heart’s left side. Blood is carried from the heart’s left side to the body with the help of the Aorta, which is the main artery inside the human body.
Capillaries, having thin walls, allow the movement of oxygen, nutrients, carbon dioxide, and waste products across their walls to and from the cells of tissues. The process starts again once veins carry the deoxygenated blood back to the heart.
