anatomy cardiovascular system- circulatory system

how do arteries carry blood?

arteries carry blood away from the heart

how do veins carry blood

veins carry blood back towards the heart

what blood do arteries contain?

oxygenated blood

what blood do veins contain?

deoxygenated blood 

what percent of blood is at rest in the veins

60%

what are the three layers of the veins and arteries

1. Tunica interna (intima)

2. Tunica media (muscularis)

3. Tunica externa (adventitia) 

what is the additional structure in veins

valves

what happens if valves in the veins weaken

varicose veins are a result

Tunica interna (intima)

is the inner layer composed of endothelial cells

Tunica media (muscularis)

is the middle layer composed of smooth muscle

Tunica externa (adventitia)

loose fibrous connective tissue

what are the cause of varicose veins 

1. Pregnancy 

2. obesity 

3. genetics 

4. occupation 

what happens when there is a weak area in the wall of an artery

An ANEURYSM which may rupture