Anatomy 1352: Unit 3 Part 2 - The Heart

Introduction

• Overview of arteries and veins.
• Blood circulation: veins bring blood to the heart; arteries carry it away.
• Detailed discussion on arteries and veins in Unit 4.

Arteries

• Function: Carry blood away from the heart.
• Details:
  • Blood from ventricles enters arteries through semilunar valves.
  • Typically carry oxygen-rich blood except pulmonary arteries (oxygen-poor).
  • Arteries have thicker walls due to high pressure.
  • Arteries thin out further from the heart as pressure decreases.

Veins

• Function: Return blood to the heart.
• Details:
  • Carry deoxygenated (oxygen-poor) blood.
  • Lower pressure, thinner walls.
  • Have valves to maintain blood flow direction.
  • Exception: Pulmonary veins carry oxygenated blood.

Major Arteries and Veins

• Arteries:
  • Aorta: largest artery.
  • Pulmonary trunk and arteries: lead to lungs.
  • Coronary arteries: supply heart muscle.
• Veins:
  • Vena Cava: superior and inferior, return blood to the right atrium.
  • Pulmonary veins: return oxygenated blood to the left atrium.
  • Coronary sinus: collects blood from coronary veins.

Circulatory Circuits

• Systemic Circulation:
  • Delivers oxygen to the body, returns CO2.
  • Path: aorta ➜ body ➜ vena cava ➜ heart.
• Pulmonary Circulation:
  • Delivers CO2 to lungs, picks up oxygen.
  • Path: right ventricle ➜ pulmonary trunk ➜ lungs ➜ pulmonary veins ➜ heart.
• Visual Aid: Draw a diagram to visualize the circulation paths.

Heart Defects

• Coarctation of the Aorta:
  • Narrowing of aorta, increased pressure on left ventricle.
• Tetralogy of Fallot:
  • Four heart defects, needs immediate surgery.
  • Causes cyanosis due to poor oxygenation.

Coronary Circulation

• Coronary arteries supply oxygen to heart muscle.
• Coronary circulation is not continuous; occurs when ventricles relax.
• Coronary vessels come off the first inch of the aorta.

Coronary Artery Disease (CAD)

• Leading cause of death in men and women.
• Causes: Plaque buildup in coronary arteries, reducing blood flow.
• Risk Factors: Smoking, high blood pressure, diabetes, high cholesterol, obesity, stress, sedentary lifestyle, family history.
• Diagnosis: EKG, stress test, cardiac catheterization.

Treatments for CAD

• Bypass Surgery: Rerouting blood around blockage.
• Angioplasty and Stents:
  • Angioplasty: Balloon to open narrowed arteries.
  • Stent: Wire tube to keep artery open.

Summary

• Understanding major arteries and veins is crucial for comprehending circulatory paths.
• Recognize symptoms and treatments for coronary artery disease.
• Visual aids and diagrams are helpful to visualize blood circulation.

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This concludes part two. Next, we will discuss the cardiac muscle and electrical conduction in part three.