1. BLOOD VESSEL NOTES

2. VASCULAR SYSTEM Take blood to tissues and back
Arteries –carries blood away from heart
Arterioles – “small arteries”
found between arteries and capillaries

3. Capillaries – smallest of blood vessels and sites of gas exchange between blood and tissue cells
connects arterioles and venules

4. Venules – “small veins”
Connects capillaries and veins
Veins –return blood toward heart

6. BLOOD VESSEL ANATOMY Tunica (layer) intima
Endothelium (inner lining of blood vessels)
Tunica media
Middle, smooth muscle layer; controls (sympathetic nervous system) diameter of blood vessel

7. Tunic externa
Outermost, fibrous connective tissue

8. DIFFERENCES BETWEEN BLOOD VESSEL TYPES
Arteries
Thickest layer; carry high pressure blood
Blood pumped by force of heart

9. Veins
Lumens (space inside of blood vessels) of veins are larger
Use “milking” action of muscles to help move blood

10. Capillaries
Only one cell thick
Gas exchange between blood and tissue

11. Capillary beds (interweaving network of capillaries) consist of two types of vessels
Vascular shunt – directly connects an arteriole to a venule
True capillaries – gas exchange by diffusion (high to low concentration)