The walls of the heart are formed by three layers, which from the inside to the outside are:
- endocardium → endothelium (simple floor epithelium) covers the inner walls (atria, ventricles, and continues with the endothelium of afferent and efferent vessels, which enter and exit the heart). It rests on the lamina propria, which has elastic fibers, while still below we find loose connective tissue with trophic function.
- myocardium → striated muscle tissue (typical of the heart); it presents two different systems , one for the atria and one for the ventricles, separated by the fibrous skeleton of the heart to which the fibrous muscle cells are attached. Fibrous disks also attack the heart valves . For the walls of the heart we speak of a common myocardium, while for the conduction system of the heart we speak of a specific myocardium .
- epicardium → Corresponds to the visceral leaflet of the serous pericardium. It internally wraps the outer surface of the heart , giving it a smooth and translucent appearance, up to the origin of the large vases emerging from the heart. It is a serous membrane, made up of mesothelial cells resting on a connective lamina. Below is the subepicardial (connective) layer in which the coronary vessels run. Presents accumulations of adipose tissue in some portions.
⇑ READ ALSO: Macroscopic anatomy of the heart
⇓ READ ALSO: Myocardium