1. Cardiovascular System Notes:
Blood Vessels

2. Interesting Cardiovascular System Fact
The human body has 60,000 miles of blood vessels – long enough to go almost 3 times around the Earth!

3. NOTES – THE CARDIOVASCULAR SYSTEM (A.K.A. THE CIRCULATORY SYSTEM)
3 main parts
heart
blood
blood vessels

4. Blood Vessels
ARTERIES
take blood away from the heart

5. 3 layers
1. TUNICA EXTERNA: outside layer – made up of connective tissue

6. 3 layers
2. TUNICA MEDIA: middle layer – made up of smooth muscle

7. 3 layers
3. TUNICA INTIMA: inner layer – made up of endothelial cells (endothelium)

8. VEINS
bring blood to the heart
same 3 layers as arteries except the muscular layer is much smaller
also contain valves

9. EX: oxygen, nutrients, waste
Capillaries
(photomicrograph of alveolar capillaries)
Function: the exchange of materials between the blood and the body’s cells
EX: oxygen, nutrients, waste
these are microscopic in size