The Circulatory System

Your heart and blood vessels make up the circulatory system. The main function of the circulatory system is to provide oxygen, nutrients and hormones to muscles, tissues, and organs throughout your body. Another function of the circulatory system is to remove waste from cells and organs so your body can dispose of it.

Your heart pumps blood to the body through a network of arteries and veins (blood vessels). Your circulatory system can also be defined as your cardiovascular system. Cardio means heart, and vascular refers to blood vessels.

The circulatory system’s function is to move blood throughout the body. This blood circulation keeps organs, muscles, and tissues healthy and working to keep you alive.

The circulatory system also helps your body get rid of waste products. This waste includes:

  • Carbon dioxide from respiration (breathing)
  • Other chemical by-products from your organs
  • Waste from things you eat and drink

Your circulatory system functions with the help of blood vessels that include arteries, veins, and capillaries. These blood vessels work with your heart and lungs to continuously circulate blood through your body.

Here’s how:

  1. The heart’s bottom right pumping chamber (right ventricle) sends blood that’s low in oxygen (oxygen-poor blood) to the lungs. Blood travels through the pulmonary trunk (the main pulmonary artery).
  2. Blood cells pick up oxygen in the lungs.
  3. Pulmonary veins carry the oxygenated blood from the lungs to the heart’s left atrium (upper heart chamber).
  4. The left atrium sends the oxygenated blood into the left ventricle (lower chamber). This muscular part of the heart pumps blood out to the body through the arteries.
  5. As it moves through your body and organs, blood collects and drops off nutrients, hormones and waste products.
  6. The veins carry deoxygenated blood and carbon dioxide back to the heart, which sends the blood to the lungs.
  7. Your lungs get rid of the carbon dioxide when you exhale.
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