1. Heart: valves, vessels and nodal tissue
Blood vessels: structure and function

2. Heart Valves

3. Coronary Blood vessels

4. Nodal Tissue

5. Blood vessels: Structure and Function
Arteries
Arterioles
Capillary
Venules
Veins

6. Blood vessels : Arteries
Arteries: thick, elastic walls
Lumen: holds blood
3 layers: outer connective tissue
middle layer of smooth muscle & elastic fibers (stretch)
inner endothelium
allows stretching/response to large change in pressure

7. Arterioles
carry blood away from heart/ between arteries and capillaries
vasodilation and vasoconstriction allows vessels to change diameter, affecting blood pressure and heat loss
3 layers: middle layer mostly smooth muscle surrounded by elastic fibers.
Vasodilation= elastic fibers relax=increase in diameter=decrease in blood pressure
Vasoconstriction= elastic fibers contract= decrease in diameter= increase in blood pressure

8. Capillaries
exchange of nutrients and wastes, oxygen and carbon dioxide via diffusion
connect arterioles to venules
one cell thick facilitates diffusion
highly branched capillary beds increase surface area
sphincters at beginning of some beds regulates blood flow affecting blood pressure and tissue use of nutrients & oxygen

9. Venules conduct low pressure blood from capillaries to veins
thin walls… middle layer not well developed
don’t need to be thick-walled or elastic since blood in them is under very low pressure

10. Veins Carry low-pressure blood towards heart
Act as blood reservoirs. Iif blood pressure is too low, can constrict and force more blood through system, increasing b.p.
3 layers. thin elastic layer due to low b.p.
one way valves prevent backflow of blood