Circulation of the Blood in the Body

• Systemic Circulation Loop

  • where oxygenated blood (oxygen-rich, carbon dioxide-poor) is distributed into the body’s systems
  • Oxygenated blood is pumped from the heart to other organs and tissues until it reaches the individual cells
  • carbon dioxide is collected as waste from the cells and is brought back to the heart
  • A part of this circulation loop is the coronary circulation
• Coronary circulation


  is the circulation of blood in the blood vessels of the heart muscle.
• Pulmonary Circulation Loop

  • important in refilling blood with oxygen and releasing carbon dioxide into the environment
  • When the deoxygenated blood (oxygen-poor, carbon dioxide-rich) from the systemic circulation returns to the heart, it must be immediately transferred to the lungs to be refilled with oxygen in replacement with the carbon dioxide it carries
  • The newly oxygenated blood will then return to the heart and enter the systemic circulation for the distribution of oxygen to the body systems
• Heart 


  is the organ that pumps blood into the different body systems.
• The deoxygenated blood from the different parts of the body enters the heart through two large veins, the inferior and superior vena cava.
• Deoxygenated blood enters the right atrium of the heart. The right atrium contracts and blood flows into the right ventricle through the open tricuspid valves
• Once the right ventricle is fully filled with deoxygenated blood, the tricuspid valves close to prevent backflow of blood to the right atrium during contraction of the right ventricle. As the right ventricle contracts, the blood leaves the heart through the pulmonary arteries that lead to the lungs
• Inside the lungs, the deoxygenated blood is filled with oxygen and converted to oxygenated blood. The oxygenated blood returns to the heart via the pulmonary veins and enters the left atrium of the heart.
• The left atrium contracts to push blood to the left ventricle through the open mitral valve. Once the left ventricle is fully filled with oxygenated blood, the mitral valve closes to prevent the backflow of blood into the left atrium as the ventricle contracts. During contraction of the left ventricle, the oxygenated blood leaves the heart through the aorta.
• aorta


  the largest artery in the heart that serves as the pathway for the flow of oxygenated blood to the different parts of the body
• As the oxygenated blood enters the capillaries in the organs, the cells take the oxygen and release the carbon dioxide making the blood deoxygenated. Deoxygenated blood from the upper body enters the superior vena cava while those from the lower portion enter through the inferior vena cava.
• Pulse

  • direct measure of the heart rate
  • easiest to find on the wrist or neck
  • the heart pumps, the arteries expand and contract and create a heartbeat
• Pulse rate

  • is the number of times your heart beats in one minute
  • this may vary from one individual to the other
  • factors like age, gender, and exposure to strenuous activities can affect the pulse rate
• The simpler the activity is, the lower the pulse rate. Inversely, when doing a tiring activity like exercise the heart beats faster to produce more oxygen-rich blood needed by the body. Thus, the pulse rate increases.