Heart Structure and Circulation

Introduction

• Understanding the structure and function of the heart.
• Focus on differences between single and double circulatory systems.

Circulation in Fish

• Fish have a single circulatory system.
  • Deoxygenated blood is pumped from the heart to the gills.
  • Blood collects oxygen in the gills and becomes oxygenated.
  • Oxygenated blood travels from the gills to the organs.
  • Oxygen diffuses into body cells, and blood returns to the heart.
• Disadvantage:
  • Blood loses pressure at the gills, resulting in slower oxygen delivery to organs.

Human Double Circulatory System

• Double Circulatory System:
  • Deoxygenated blood pumped from heart to lungs to collect oxygen.
  • Oxygenated blood returns to the heart.
  • Heart pumps oxygenated blood to the organs.
  • Blood transfers oxygen to body cells and returns to the heart.
• Advantage:
  • Blood travels rapidly to body cells, delivering necessary oxygen efficiently.

Structure of the Heart

• The heart consists mainly of muscle tissue and functions to pump blood.
• Four Chambers:
  • Top: Left Atrium, Right Atrium.
  • Bottom: Left Ventricle, Right Ventricle.
  • Valves separate atria from ventricles.
• Blood flow pattern:
  • Blood enters left and right atrium.
  • Atria contract, forcing blood into ventricles.
  • Ventricles contract, pushing blood out of the heart.
  • Valves prevent backflow into atria during ventricular contraction.

Major Blood Vessels

• Vena Cava: Brings deoxygenated blood from the body to the heart.
• Pulmonary Artery: Blood moves from heart to lungs.
• Pulmonary Vein: Oxygenated blood moves from lungs to heart.
• Aorta: Blood is pumped from heart to the body.

Additional Notes

• Left Ventricle has a thicker wall than the right.
  • It pumps blood to the entire body, requiring more force.
• Right Ventricle pumps blood only to the lungs.

Coronary Arteries

• Important blood vessels that branch from the aorta.
• Spread into heart muscle to supply oxygen for muscle contraction.

Heart Rate Control

• Natural pacemaker in the right atrium regulates heart rate.
• Artificial Pacemaker can be implanted if natural pacemaker malfunctions.

Study Resources

• Practice questions available in the vision workbook accessible via the provided link.

Conclusion

• By understanding the structure and function of the heart, you can describe how it pumps blood throughout the body effectively.