circulatory system

The human circulatory system functions to transport blood and oxygen from the lungs to the various tissues of the body

arteries carry blood away from the heart

veins are blood cells that bring blood back to the heart and drain blood from organs and limbs

capillaries have one layer of cells where diffusion and exchange of materials occur

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve

some disorders of the circulatory are heart attacks and strokes when the heart works to much and starts to fail