What is function of arteries and vein capellaries?
Arteries:
1. Carry oxygenated blood away from the heart to the rest of the body: Arteries carry oxygen-rich blood from the heart to the tissues and organs of the body. The left ventricle of the heart pumps oxygenated blood into the aorta, the largest artery in the body, which then branches into smaller arteries that supply blood to specific regions and organs.
2. Maintain blood pressure: Arteries maintain blood pressure, which is the force exerted by blood against the walls of the arteries. Blood pressure is necessary for the blood to flow through the vessels and deliver oxygen and nutrients to the tissues.
Veins:
1. Carry deoxygenated blood back to the heart: Veins carry oxygen-depleted blood back to the heart. Veins have one-way valves that prevent the backflow of blood and ensure that blood flows towards the heart.
2. Reservoir for blood: Veins act as reservoirs for blood, containing about 60-70% of the total blood volume in the body. This blood reservoir helps to maintain blood pressure and ensures an adequate supply of blood to the tissues during times of increased demand, such as exercise.
Capillaries:
1. Exchange of substances between blood and tissues: Capillaries are the smallest blood vessels and form extensive networks in tissues and organs. They allow for the exchange of substances between the blood and the surrounding tissues. Oxygen, nutrients, hormones, and other substances move out of the capillaries into the tissues, while waste products, such as carbon dioxide, move from the tissues into the capillaries.
2. Regulation of fluid balance: Capillaries play a crucial role in regulating fluid balance between the blood and the tissues. The exchange of fluids and solutes across the capillary walls helps to maintain the proper balance of fluids and electrolytes in the body.
3. Defense against infection: Capillaries are involved in the body's defense against infection. They allow white blood cells and other immune cells to move out of the bloodstream into the tissues to fight infection and promote healing.