how blood flows through the heart

• Step 1 - Deoxygenated Blood Enters the Heart:

  • Deoxygenated blood (low in oxygen and high in carbon dioxide) enters the heart from the body through two large veins called the vena cavae.
  • The superior vena cava (upper body) and the inferior vena cava (lower body).
• Step 2 - Right Atrium:

  • The deoxygenated blood fills the right atrium (one of the heart's upper chambers.)
  • The right atrium contracts, pushing the blood through a one-way valve called the tricuspid valve.
• Step 3 - Right Ventricle:

  • The blood moves from the right atrium into the right ventricle (one of the heart's lower chambers.)
  • The right ventricle contracts, pushing the blood through another one-way valve called the pulmonary valve.
• Step 4 - Pulmonary Artery:

  • The blood is now in the pulmonary artery and is transported to the lungs.
  • In the lungs, the blood picks up oxygen and removes carbon dioxide. This process is called gas exchange.
• Step 5 - Pulmonary Veins:

  • The oxygenated blood returns to the heart from the lungs through four pulmonary veins. These veins carry oxygen-rich blood from the lungs to the heart's left side.
• Step 6 - Left Atrium:

  • The oxygenated blood fills the left atrium, the other upper chamber of the heart.
  • The left atrium contracts, pushing the blood through another one-way valve called the mitral valve (or bicuspid valve).
• Step 7 - Left Ventricle:

  • The blood moves from the left atrium into the left ventricle, the final destination, before being pumped to the body.
  • The left ventricle contracts forcefully, pushing the oxygenated blood through the aortic valve.
• Step 8 - Aorta:

  • The oxygenated blood is now in the aorta, the largest artery in the body.
  • The aorta carries the blood away from the heart and branches into various arteries, supplying oxygen and nutrients to all body parts.
• Step 9 - Coronary Arteries:

  • Before the aorta branches out to supply blood to the rest of the body, it also gives rise to the coronary arteries.
  • The coronary arteries are responsible for providing oxygen and nutrients to the heart muscle itself.
• Step 10 - Coronary Sinus

  1. Deoxygenated blood from the heart collects in the coronary sinus

  2. Coronary sinus returns the deoxygenated blood to the heart's right atrium

  3. Blood flow cycle through the heart and body delivers oxygen-rich blood to tissues and organs

  4. Deoxygenated blood is returned to the heart to be pumped to the lungs for reoxygenation

  5. Continuous process supplies body with necessary resources for proper functioning
• Venus Blood

  Deoxygenated blood that carries waste products back to the heart
• Arterial Blood


  Oxygenated blood that carries oxygen and nutrients to the body's tissues