Heart

Transcript

Note: Transcripts are generated using speech recognition software and may contain errors.
The heart is a muscle that pumps blood through a network of tubes called blood vessels. The blood vessels include arteries, veins and capillaries. Arteries carry oxygen rich blood away from the heart. While veins carry oxygen poor blood back to the heart capillaries connect the arteries and the veins and allow for the exchange of oxygen, nutrients and waste products between the blood and the body's tissues. The heart has four chambers that work together to pump blood throughout the blood vessels. The heart's electrical system causes it to contract and relax in a rhythmic pattern. Blood is made up of plasma, red blood cells, white blood cells and platelets. When the heart beats, it creates pressure that pushes blood through the arteries and into the capillaries. Oxygen and nutrients are exchanged between the blood and the body's tissues in the capillaries. And then the blood flows back into the veins and is carried back to the heart. The heart then pumps the oxygen rich blood out to the body's tissues again. And the process continues. The circulatory system is responsible for maintaining the body's internal balance by ensuring that all the cells have the necessary resources to function properly.