Lecture Notes: Heart Anatomy

Overview

• Instructor: Nurse Sarah
• Focus: Anatomy of the heart including chambers, great vessels, and valves.

Heart Location and Structure

• Location: Mediastinum, cavity between right and left lung, slightly left-centered, behind the sternum.
• Shape: Cone-like, upside down in the chest:
  • Base: Top, towards right shoulder.
  • Apex: Bottom, points to the left side of the body (important for measuring the apical pulse).

Heart Chambers

• Right Side:
  • Right Atrium: Receives deoxygenated blood from superior/inferior vena cava and coronary sinus.
  • Right Ventricle: Pumps deoxygenated blood to lungs via pulmonary artery.
• Left Side:
  • Left Atrium: Receives oxygenated blood from lungs via pulmonary veins.
  • Left Ventricle: Pumps oxygenated blood to body via aorta.

Blood Flow Sequence

1. Right Atrium
   • Receives blood from body: Superior/inferior vena cava and coronary sinus.
   • Structures:
     • Fossa Ovalis: Closed passageway in adults, formerly allowed fetal blood flow.
     • Pectinate Muscles: Help contract blood to right ventricle.
     • Crista Terminalis: Guides electrical impulses for contraction.
2. Right Ventricle
   • Transports blood to lungs.
   • Structures:
     • Trabeculae Carneae: Support contraction.
     • Papillary Muscles and Chordae Tendineae: Prevent valve collapse.
3. Pulmonic Valve
   • Prevents backflow into right ventricle, reliant on pressure changes.
4. Pulmonary Artery
   • Unique as it carries deoxygenated blood to lungs.
5. Left Atrium
   • Receives oxygenated blood from pulmonary veins.
   • Structures:
     • Thicker Walls: Contracts against high pressure.
6. Left Ventricle
   • Pumps blood through aortic valve and aorta.
   • Structures:
     • Thicker Walls: Needed for systemic circulation.
     • Trabeculae Carneae, Papillary Muscles, Chordae Tendineae: Ensure effective contraction.
7. Aortic Valve and Aorta
   • Connects left ventricle to systemic circulation.
   • Coronary Arteries: Supply oxygenated blood to myocardium.

Valves

• Atrioventricular Valves:
  • Tricuspid Valve: Right side; prevents backflow to atrium.
  • Mitral (Bicuspid) Valve: Left side; prevents backflow to atrium.
• Semilunar Valves:
  • Pulmonic Valve: Between right ventricle and pulmonary artery.
  • Aortic Valve: Between left ventricle and aorta.

Clinical Importance

• Apical Pulse: Important for medication administration (e.g., digoxin).
• Endocarditis Risk: From IV drug use or infections, leading to valve vegetations and potential surgeries.

Additional Learning

• Videos available on coronary arteries and heart layers.

Summary: This lecture focused on the anatomical aspects of the heart, exploring each chamber and valve's structure, function, and clinical relevance. Understanding these elements is crucial for practical nursing applications such as assessing heart function and managing cardiovascular health.