Blood Vessels

Blood vessels are a key component of the circulatory system, responsible for transporting blood throughout the body. There are three main types of blood vessels: arteries, veins, and capillaries. Each type has its own unique structure and function.

Arteries

Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. They have thick, muscular walls that allow them to withstand the high pressure produced by the pumping of the heart. Arteries also have a smaller lumen (the inner space of the vessel) compared to veins.

Veins

Veins are blood vessels that carry deoxygenated blood back to the heart. They have thinner walls and larger lumens than arteries, as the blood pressure in veins is lower. Veins also have one-way valves to prevent the backflow of blood.

Capillaries

Capillaries are tiny, thin-walled blood vessels where the exchange of oxygen, nutrients, and waste products occurs between the blood and tissues. They have a large surface area to facilitate this exchange.

Study Guide

1. What are the three main types of blood vessels?
2. What is the function of arteries?
3. How do veins differ in structure from arteries?
4. Where does the exchange of oxygen and nutrients occur in the circulatory system?