The Heart and Lungs

The heart and circulatory system is also called the cardiovascular (heart and blood vessels) system. Blood travels through the circulatory system carrying nutrients and oxygen to cells and waste away from cells. The heart is the pump that sends blood throughout the body’s network of blood vessels. It usually beats between 60-100 times each minute, or over 100,000 times every day. About 2 gallons or 5 liters of blood move throughout your body every day. Arteries carry blood away from the heart and veins carry blood back to the heart.

The heart is the key organ in the circulatory system. It is made up of four rooms, or chambers, that are enclosed by thick, muscular walls. The top two chambers are called the right and left atriums (together, they are the atria). Atriums are chambers that are open, or have openings, in the top of them. The bottom two chambers are the right and left ventricles. They pump blood out of the heart. The atria receive blood entering the heart. The right atrium is the top chamber on the right…