Heart Anatomy and Physiology Lecture

Overview

• Topics Covered: Location, anatomy, blood flow, and histology of the heart.
• Circuits:
  • Pulmonary Circuit: Right side of the heart (right atrium and ventricle); pumps deoxygenated blood to the lungs.
  • Systemic Circuit: Left side of the heart (left atrium and ventricle); pumps oxygenated blood to the body.

Heart Structure

• Pericardial Cavity:
  • Closest cavity to the heart; contains pericardial fluid that acts as lubricant and support.
  • Consists of layers: endocardium (simple squamous epithelium), myocardium (cardiac muscle), and fibrous pericardium (dense irregular connective tissue).

Heart Chambers and Valves

• Atrium and Ventricles:
  • Atria are on top; ventricles are below.
  • Right side receives blood from the body and sends it to the lungs.
  • Left side receives blood from the lungs and sends it to the body.
• Valves:
  • Tricuspid Valve: Right atrioventricular, between right atrium and ventricle.
  • Bicuspid (Mitral) Valve: Between left atrium and ventricle; associated with strength (biceps analogy).
  • Semilunar Valves: Located at exits of ventricles (aortic and pulmonary).

Internal Heart Structures

• Chordae Tendineae: Attach to valves and papillary muscles to prevent backflow into atria.
• Papillary Muscles: Connect chordae tendineae to heart wall.
• Septum:
  • Interventricular: Separates ventricles.
  • Interatrial: Separates atria.
• Fossa Ovalis: Remnant of fetal circulation, a closed hole between atria.

Blood Flow Pathway

1. Blood enters the right atrium from the body.
2. Flows through the tricuspid valve to the right ventricle.
3. Exits via pulmonary semilunar valve into pulmonary trunk and arteries.
4. Returns oxygenated via pulmonary veins to left atrium.
5. Flows through the bicuspid valve to the left ventricle.
6. Exits via aortic semilunar valve to the aorta and the body.

Circulatory Vessels

• Vena Cavae:
  • Superior and inferior, return deoxygenated blood to the heart.
• Pulmonary Veins: Bring oxygenated blood from lungs to heart.
• Aorta: Distributes oxygenated blood from the left ventricle to the body.
• Pulmonary Trunk: Carries deoxygenated blood from right ventricle to lungs.

Histology of the Heart

• Cardiac Muscle:
  • Striated, with visible actin and myosin filaments.
  • Contains intercalated discs (containing gap junctions for electrical signal transfer and desmosomes for cell adhesion).

Conclusion

• Review lecture materials and supplementary videos and photos for a deeper understanding.