Heart Anatomy 101 💖

Introduction

• The heart is a hollow muscular organ located in the thoracic cavity.
• It is essential to learn the basic anatomical terminology and structures of the heart.
• Anatomical perspectives: When looking at a heart, remember it's like looking at someone else's heart.

Basic Structure

• Main Bottom Chambers (Ventricles)
  • Left Ventricle: Thicker muscular wall, pumps blood all around the body (systemic circulation).
  • Right Ventricle: Thinner muscular wall, pumps blood to the lungs.

Valves of the Heart

• Left Side Valves
  • Valve between Left Atrium and Left Ventricle: Mitral Valve (also known as Bicuspid Valve) – has 2 cusps.
  • Valve between Left Ventricle and Aorta: Aortic Valve (Aortic Semilunar Valve).
• Right Side Valves
  • Valve between Right Atrium and Right Ventricle: Tricuspid Valve – has 3 cusps.
  • Valve between Right Ventricle and Pulmonary Artery: Pulmonary Valve (Pulmonary Semilunar Valve).

Chambers and Blood Flow

• Left Atrium and Left Ventricle
  • Pulmonary Veins: Four veins that bring oxygenated blood from the lungs to the left atrium.
  • Blood pathway: Pulmonary veins → Left Atrium → Mitral Valve → Left Ventricle → Aortic Valve → Aorta → Systemic circulation.
• Right Atrium and Right Ventricle
  • Superior and Inferior Vena Cava: Largest veins bringing deoxygenated blood from the body to the right atrium.
  • Blood pathway: Superior/Inferior Vena Cava → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Valve → Pulmonary Artery → Lungs.

Supporting Structures

• Tendinous Cords (Chordae Tendineae): Prevent valves from regurgitating blood back into the atria.
• Papillary Muscles: Connect tendinous cords to the heart wall.

Layers of the Heart

• Pericardium: Fibrous sac around the heart providing protection and preventing over-expansion.
• Endocardium: Inner layer of squamous vascular endothelial cells, ensuring smooth blood flow.
• Myocardium: Thick muscular layer responsible for heart contractions (cardiac muscle).

Septum

• Cardiac Septum: Tissue separating the left and right sides of the heart.
  • Left Side: Known as the Body Pump (pumps blood to the body).
  • Right Side: Known as the Lung Pump (pumps blood to the lungs).

Summary

• The heart consists of the four chambers, specific valves, and supporting structures to ensure one-way blood flow and efficient circulation.
• Understanding the anatomy and flow through the heart is crucial for further studying its function.