Ertwr Essay, Research Paper

Oxygen-poor blood from the body flows down through the RIGHT ATRIUM to fill the RIGHT VENTRICLE which pumps the blood out through the PULMONARY ARTERY to the lungs.

As blood flows through the LUNGS it gives up the waste carbon dioxide and gains more oxygen from the inhaled air. The freshly oxygenated blood returns to the left atrium of the heart by way of the PULMONARY VEINS.

Oxygen-rich blood from the lungs flows down through the LEFT ATRIUM to fill the LEFT VENTRICLE which pumps it into the AORTA, the main artery to the body.

The blood passes from the aorta into smaller ARTERIES which carry it to all body organs and tissues. There it flows into the smalles arterial branches, the ARTERIOLES.

From the arterioles, blood flows into dense networks of tiny, thin-walled blood vessels called CAPILLARIES. Oxygen and nutrients in the blood easily pass through the thin capillary walls to the cells, and carbon dioxide and other cellular waste products can pass back through the walls into the blood to be carried away.