Circulatory System: Pathway of Blood through the Heart

Blood Vessels

• Veins: Carry blood to the heart.
• Arteries: Carry blood away from the heart.
• Color Coding:
  • Blue: Represents deoxygenated blood.
  • Red: Represents oxygenated blood from the lungs.

Blood Flow Pathway

Entry to the Heart

• Superior Vena Cava: Receives blood from head, neck, upper limbs, and chest.
• Inferior Vena Cava: Receives blood from the trunk, viscera, and lower limbs.
• Both vena cavae drain into the Right Atrium.

Right Side of the Heart

• Blood flows from the right atrium to the Right Ventricle through the Tricuspid Valve (three flaps).
• It exits the right ventricle through the Pulmonary Valve into the Pulmonary Artery.
  • Pulmonary Artery: Carries deoxygenated blood to the lungs (though an artery, it carries blood away from the heart).

Gas Exchange in the Lungs

• Pulmonary Arteries divide into left and right, leading to respective lungs.
• Gas Exchange: Blood releases carbon dioxide and absorbs oxygen.

Return to the Heart

• Oxygenated blood returns to the heart through the Pulmonary Veins into the Left Atrium.

Left Side of the Heart

• Blood moves from the left atrium to the Left Ventricle via the Mitral Valve (Bicuspid Valve).
• It exits the left ventricle through the Aortic Semilunar Valve into the Aortic Arch.

Distribution of Oxygenated Blood

• Aorta: Largest artery that distributes oxygenated blood.
  • Aortic Arch: Has three major branches to supply head and arms.
  • Descending Aorta: Continues through the chest and abdomen.
    • Splits in the abdomen to supply blood to the pelvis and legs.

Additional Notes

• Valves in the heart ensure one-way blood flow and prevent backflow.

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