Understanding Blood Flow Through the Heart

Introduction

• Common advice: "Follow your heart" is literal for red blood cells.
• The heart is a muscular organ that pumps blood.
• Diagramming the path of blood flow through the heart and vessels.

Heart Structure

• Left and Right Orientation:
  • The diagram's left and right are opposite to the observer's.
• Heart Chambers:
  • Right Atrium
  • Right Ventricle
  • Left Atrium
  • Left Ventricle
• Valves:
  • Tricuspid Valve (Right Side)
  • Mitral/Bicuspid Valve (Left Side)
  • Pulmonary Semilunar Valve
  • Aortic Semilunar Valve

Blood Flow Pathway

• Deoxygenated Blood (Blue):

  • Begins in the Right Atrium.
  • Flows through the Tricuspid Valve to the Right Ventricle.
  • Pumps through the Pulmonary Semilunar Valve to the Pulmonary Arteries.
  • Travels to the lungs to exchange CO2 for O2.

• Oxygenated Blood (Red):

  • Returns via Pulmonary Veins to the Left Atrium.
  • Passes through the Mitral Valve into the Left Ventricle.
  • Pumps through the Aortic Semilunar Valve into the Aorta.

Aorta and Coronary Arteries

• Aorta:
  • Largest artery; distributes oxygenated blood.
  • Aortic Arch and Descending Aorta supply upper and lower body.
• Coronary Arteries:
  • Branch from the Aorta.
  • Supply heart muscle with blood.
  • Blockage can cause a heart attack.

Returning Blood to the Heart

• Capillary Exchange:
  • Blood gives oxygen and collects CO2 in tissue capillaries.
• Veins:
  • Superior Vena Cava (Upper body)
  • Inferior Vena Cava (Lower body)
  • Return blood to the Right Atrium.

Recap of Blood Flow Path

1. Right Atrium → Tricuspid Valve → Right Ventricle
2. Pulmonary Semilunar Valve → Pulmonary Arteries → Lungs
3. Pulmonary Veins → Left Atrium → Mitral Valve
4. Left Ventricle → Aortic Semilunar Valve → Aorta
5. Aortic Arch → Upper Body / Descending Aorta → Lower Body
6. Superior/Inferior Vena Cavas → Right Atrium

Practice and Learning Tips

• Practice tracing the blood flow path.
• Memorize each stage and structure involved.
• Try identifying parts on an unlabeled diagram.

Fun Fact

• Heart sounds are not from the heart pumping but from valves snapping shut.