Anatomy (Cardiovascular system) · MU Sofia

104. Structure of the cardiac wall. Fibrous skeleton of the heart.

Covers the three layers of the cardiac wall: the epicardium, the thick myocardium with its cardiomyocytes and intercalated discs, and the endocardium, with a note on the thinner atrial walls. It then describes the atrial and ventricular muscle arrangement, and the cardiac skeleton with its fibrous rings, fibrous triangles, infundibular tendon and membranous septum, using Latin names.

Inside: 3 sections · 3 labelled pictures · 14 flashcards · 4 min

Topic 3 of 36 in the MU Sofia syllabus for Anatomy (Cardiovascular system) (Medicine, Year 2). The free AceMed note covers it in 3 sections, about 503 words (4 min of reading), with 14 flashcards.

In this note

  1. CARDIAC WALL
  2. Layers of the cardiac wall :
  3. CARDIAC SKELETON

CARDIAC WALL

  • The cardiac wall or myocardium is the muscular tissue of the heart, responsible for contracting & pumping blood.

Layers of the cardiac wall :

1. Epicardium:

  • The outermost layer.
  • It is the visceral layer of the serous membrane.
  • Made of mesothelial cells , below them is a layer of adipose and connective tissue.
  • Nerves and blood vessels that supply the heart are found in the epicardium.
  • Function: provides a protective outer covering for the heart.

3. Endocardium:

  • Inner layer
  • Consists of endothelial cells ,which are simple squamous epithelial tissue layer and a thin layer of loose connective tissue.
  • lines the cavity and valves.
  • “pericardium”
  1. 1. Serous pericardium
  2. 2. Fibrous pericardium.

* The atria have relatively thin walls compared to the ventricles, because they primarly recieve blood rather than pumping it.

2. Myocardium:

  • Function:
  • conduct Action potential
  • contraction
  • The middle and thickest layer.
  • It is a muscular layer that enables heart layers
  • Made of cardiac muscle cells (cardimyocytes)
  • Have a single nucleus in the center of the cell, which helps to distinguish them from skeletal muscle cells that have multiple nuclei dispersed in the periphery of the cell.
  • The cardiomyocytes are connected with each other through the intercalated discs.

Atrial muscle

  • The atrial myocardium can be divided into :
  1. 1. Superficial layer: Extends over both atria and thicker along its anterior compared to the posterior aspect.
  2. 2. Deep layer: Contained looped fiber or annular fibers that passes to the artioventricul boundary also encircle the venous orifices.

Ventricular muscle :

  1. 1. Subepicardial layer:
  • Runs horizontaly about the surface of the right atrium.
  • // longitudinally from the left atrium.
  • At the Apex both ventricle subepicardial muscle forms a vortex of the heart. They curve around and forms the inner subendocardi
  1. 2. Middle- Present in left ventricle and interventricular septum.
  2. 3. Subendocardium: Contributes to formation of the trabeculae carneae and papillary muscles.

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