Anatomy of the Heart

Orientation and Surfaces

• Anterior Surface: The front side of the heart.
• Posterior Surface: The back side of the heart.
• Inferior Surface: The bottom portion.
• Superior Surface: Top section where the base points towards the right shoulder.
• Apex: The pointed, bottom end of the heart.

Heart Structures Overview

Auricles

• Left Auricle: A fatty pouch with muscle tissue aiding blood flow into the atria.
• Right Auricle: Similar structure as the left, visible on the anterior surface.

Major Vessels

• Pulmonary Trunk: Carries deoxygenated blood from the right ventricle to the lungs.
• Aorta: Major artery, consisting of:
  • Ascending Aorta
  • Aortic Arch with branches:
    • Brachiocephalic Artery: Splits into right subclavian and right common carotid.
    • Left Common Carotid Artery
    • Left Subclavian Artery
  • Descending Aorta: Continues as thoracic and abdominal aorta.

Right Side Structures

• Right Atrium: Receives deoxygenated blood.
• Superior Vena Cava: Formed by the joining of right and left brachiocephalic veins.
• Azygos Vein: Feeds into the superior vena cava, bypasses the inferior vena cava.

Circulatory Pathways

Pulmonary Circulation

• Pulmonary Arteries: Carry deoxygenated blood to the lungs (appear blue).
• Pulmonary Veins: Return oxygenated blood to the heart (appear red).

Coronary Circulation

• Coronary Arteries:
  • Right Coronary Artery: Runs down the coronary sulcus.
  • Left Coronary Artery: Gives rise to:
    • Anterior Interventricular Artery (LAD): Common site for myocardial infarctions.
    • Circumflex Artery: Supplies lateral walls of the left ventricle.
• Cardiac Veins:
  • Great Cardiac Vein: Runs alongside the LAD.
  • Middle Cardiac Vein: Alongside the posterior interventricular artery.
  • Coronary Sinus: Collects blood from cardiac veins, dumps into right atrium.

Heart Valves

• Tricuspid Valve: Between right atrium and right ventricle.
• Pulmonary Semilunar Valve: At the exit of the right ventricle to the pulmonary trunk.
• Mitral (Bicuspid) Valve: Between left atrium and left ventricle.
• Aortic Semilunar Valve: Prevents backflow from aorta into left ventricle.

Internal Structures

• Chordae Tendineae: Collagen cords attached to valve leaflets.
• Papillary Muscles: Anchor chordae tendineae.
• Fossa Ovalis: Remnant of fetal circulation's foramen ovale.
• Ligamentum Arteriosum: Remnant of fetal ductus arteriosus.

Muscle and Tissue Layers

• Myocardium: Cardiac muscle layer of the heart.
• Endocardium: Lines internal chambers; made of simple squamous epithelial tissue.
• Epicardium (Mesothelium): Outer layer of the heart, composed of simple squamous epithelial tissue and areolar connective tissue.

Wall Muscles

• Pectinate Muscles: Found in atrial walls.
• Trabeculae Carne: Found in ventricular walls.

Arterial Anastomoses

• Anastomoses: Provide collateral routes for blood flow between coronary arteries to ensure oxygen delivery despite blockages.

This summary captures the key anatomical features and functions of the heart, including its structures, circulation pathways, and associated vessels and tissues. Understanding these concepts is crucial for comprehending the heart's role in the circulatory system.