Lecture Notes on The Heart

Structure of the Heart

• Four Chambers
  • Right Atrium
  • Left Atrium
  • Right Ventricle
  • Left Ventricle
• Four Valves
  • Tricuspid Valve (right side)
  • Pulmonary Valve (right side)
  • Mitral Valve (left side)
  • Aortic Valve (left side)

Function of Valves

• Valves act like one-way doors
• Ensure blood flows in the correct direction

Circulatory System

• Veins carry blood to the heart
  • Superior Vena Cava: delivers deoxygenated blood from the head, neck, arms, and chest
  • Inferior Vena Cava: delivers deoxygenated blood from the abdomen, legs, feet, etc.
  • Pulmonary Vein: carries oxygenated blood from the lungs to the heart
• Arteries carry blood away from the heart
  • Aorta: main artery carrying oxygenated blood to the rest of the body
  • Pulmonary Artery: carries deoxygenated blood from the heart to the lungs

Blood Flow Process

1. Deoxygenated blood enters the right atrium via the superior and inferior vena cava
2. Right atrium contracts, blood flows through the tricuspid valve into the right ventricle
3. Right ventricle contracts, blood flows through the pulmonary valve into the pulmonary artery and is sent to the lungs
4. Oxygenated blood from the lungs enters the left atrium via the pulmonary veins
5. Left atrium contracts, blood flows through the mitral valve into the left ventricle
6. Left ventricle contracts, blood flows through the aortic valve into the aorta
7. Blood is then distributed around the body via arteries

Key Points

• Blood enters and exits the heart from both sides in one heartbeat