What Are the 3 Parts of the Circulatory System?

Medically Reviewed on 1/6/2022
What Are the 3 Parts of the Circulatory System
The circulatory system consists of three main parts: heart, blood vessels, and blood. Learn how the circulatory system works and how to prevent diseases

The circulatory system consists of three main parts: 

  • Heart
  • Blood vessels
  • Blood

It also has three circuits that work together to circulate blood throughout the body:

  • Pulmonary: Carries deoxygenated blood from the heart to lungs, then returns oxygen-filled blood to the heart.
  • Systemic: Transports blood with oxygen, nutrients, and hormones from the heart to the rest of the body, then returns deoxygenated blood to the heart.
  • Coronary: Supplies oxygenated blood to the heart muscle, then returns oxygen-lacking blood to the lungs for oxygen supply.

What does the circulatory system do?

The heart pumps blood throughout the body through a network of arteries and veins in a continuous cycle. The cardiovascular system is responsible for transporting oxygen, nutrients, and hormones to muscles, tissues, and organs. 

It also removes waste products, such as:

  • Carbon dioxide from breathing
  • Chemical byproducts from different organs
  • Waste from foods and beverages consumed

How does the circulatory system work?

Blood vessels along with the heart and lungs continuously circulate blood through your body:

  • The right ventricles (lower chamber of the heart) sends deoxygenated blood to the lungs through the pulmonary artery.
  • Blood cells absorb oxygen from the lungs.
  • Pulmonary veins transport oxygenated blood from the lungs to the left atrium (upper chamber of the heart).
  • The left atrium transports oxygenated blood to the left ventricles, which pump blood to different muscles, tissues, and organs through the arteries.
  • The blood carries oxygen, hormones, and nutrients and takes waste products from organs.
  • The veins carry deoxygenated blood and carbon dioxide back to the heart and transport blood to the lungs.
  • The lungs get rid of the carbon dioxide through exhaling.

What are diseases of the circulatory system?

How can you prevent diseases of the circulatory system?

Lifestyle changes can help prevent diseases of the circulatory system:

  • Exercise regularly
  • Quit smoking
  • Eat a healthy, nutritious diet
  • Keep your weight under control
  • Go for regular medical checkups (lipid levels, homocysteine levels,and cardiac markers)
  • Talk to your doctor if you have a family history of heart diseases


In the U.S., 1 in every 4 deaths is caused by heart disease. See Answer
Medically Reviewed on 1/6/2022
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