1. 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

2. Five main types of blood vessels
Artery
Vein
Arteriole
Venule
Capillaries

3. Five main types of blood vessels

4. 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

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

6. 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

7. 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

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

9. 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

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