Cardiovascular System Notes: Blood Vessels

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

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

Blood Vessels ARTERIES take blood away from the heart

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

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

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

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

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