Lesson objectives To name the five main types of blood vessels To describe the difference between arteries and veins To name the main arteries and veins of the arm and leg

Five main types of blood vessels Artery Vein Arteriole Venule Capillaries

Five main types of blood vessels

Arteries Structure: thick-walled, elastic hollow tubes Same basic construction: - fibrous outer layer - middle layer of muscle and elastic tissue - inner layer made of thin squamous epithelial tissue

Arteries Function: systemic arteries carry oxygenated blood from heart to body Pulmonary artery carries deoxygenated blood to lungs

Arterioles Smaller version of arteries Structure: similar structure to arteries Function: arterioles are able to relax and dilate when more oxygen and nutrients required e.g. muscles during exercise

Capillaries Structure: smallest of blood vessels Walls only one cell thick and porous, allowing passage of gases (e.g. oxygen) and nutrients Function: to distribute essential oxygen and nutrients to most parts of body

Venules Structure: small veins Function: to carry deoxygenated blood from capillaries to larger veins

Veins Structure: walls made of three layers Walls thinner than arteries Action of skeletal muscle pushes blood through vessels and valves prevent backflow of blood Function: systemic veins carry deoxygenated blood to heart Pulmonary veins carry oxygenated blood to heart

Structure of Arteries and Veins Inner layer Elastin Middle layer Outer layer Thin membrane