❤️

Understanding Heart Structure and Function

Apr 26, 2025

Lecture Notes: Structure and Function of the Heart

Introduction

  • The heart is slightly tilted to the right in the chest.
  • Two main colors for diagrams:
    • Blue: Deoxygenated blood (right side of the heart).
    • Red: Oxygenated blood (left side of the heart).

Structure of the Heart

  • Chambers of the Heart:

    • Right Atrium (RA)
    • Left Atrium (LA)
    • Right Ventricle (RV)
    • Left Ventricle (LV)
  • Apex of the Heart: Bottom area, peak or point of the heart.

  • Base of the Heart: Superior region, the right side and a bit of the left.

  • Location in the Body: The heart sits in the mediastinum of the thoracic cavity.

Blood Flow Basics

  • Arteries: Carry blood away from the heart ("a" for "away").
  • Veins: Bring blood back to the heart.

Heart Lining and Structure

  • Muscle of the Heart (Myocardium): Thick layer (myo = muscle).
  • Endocardium: Inner layer of the heart (endo = inner).
  • Visceral Pericardium (Epicardium): Outer layer on top of the heart.
  • Parietal Pericardium (Serous Pericardium): Middle layer forming the pericardial sac.
  • Fibrous Pericardium: Tough outer layer for protection.
  • Pericardial Space: Contains pericardial fluid to reduce friction.

Blood Flow Through the Heart

  • Deoxygenated Blood:

    • Enters RA from the body via the superior and inferior vena cava.
    • From RA to RV through the tricuspid valve.
    • RV to lungs via pulmonary valve and pulmonary arteries.
  • Oxygenated Blood:

    • Returns from lungs to LA via pulmonary veins.
    • LA to LV through the bicuspid (mitral) valve.
    • LV to body via aortic valve and aorta.

Key Valves

  • Tricuspid Valve: Between RA and RV.
  • Pulmonary Valve: From RV to pulmonary trunk.
  • Bicuspid (Mitral) Valve: Between LA and LV.
  • Aortic Valve: From LV to aorta.

Blood Vessels and Aorta

  • Coronary Arteries: Supply blood to the heart itself.

    • Left Coronary Artery
    • Right Coronary Artery
    • Left Anterior Descending Artery
  • Parts of the Aorta:

    • Ascending Aorta
    • Aortic Arch
    • Descending Aorta
    • Thoracic Aorta (above diaphragm)
    • Abdominal Aorta (below diaphragm)
  • Branches off Aortic Arch:

    • Brachiocephalic Trunk
    • Right and Left Common Carotid Arteries
    • Right and Left Subclavian Arteries
    • Right and Left Vertebral Arteries

Internal Structures

  • Interatrial Septum: Separates RA and LA.
  • Interventricular Septum: Separates RV and LV.
  • Auricles and Pectinate Muscles: Muscles on atrial walls.
  • Trabeculae Carneae: Internal ridges in the ventricles.
  • Papillary Muscles and Chorda Tendineae: Contract to close valves, essential for valve function.

Summary

  • We covered the basic structure of the heart, its linings, and how blood flows through the heart.
  • Discussed major blood vessels and internal structures, concluding the detailed overview of the heart's anatomy and function.