What is the subendocardial layer?

[ sŭb′ĕn-dō-kär′dē-əl ] n. The layer of loose connective tissue that joins the endocardium and myocardium.

Where is the subendocardial layer located?

The endocardium is composed of the endothelium and the subendothelial connective tissue layer. The subendocardium is found between the endocardium and myocardium and contains the impulse-conducting system.

What is the subendocardial layer made of?

The subendocardium lies deep to the endocardium and binds the latter to the myocardium. This layer contains thick elastic and collagen fibers and a prominent number of blood vessels, mostly continuous capillaries and some arterioles.

What are the three layers of the myocardium?

The walls of the heart are composed of three layers: Epicardium – the outer layer. Myocardium – the middle, muscular layer. Endocardium – the inner layer.

Is the Subendocardium part of the myocardium?

The endocardium has two layers. The inner layer lines the heart chambers and is made of endothelial cells. Superiorly, is the second layer: a subendocardial connective tissue which is continuous with the connective tissue of the myocardium.

What is Subendocardial damage?

Most forms of heart disease cause myocardial damage which often is confined to the deep (subendocardial) layer of left ventricular muscle. Much clinical and experimental evidence suggests that subendocardial muscle is prone to ischaemic damage, and a physiological mechanism for this vulnerability is described.

Are Purkinje fibers in the myocardium?

Notice that in the lower right image I found purkinje fibers within the myocardium. Purkinje fibers are specialized conductive myocardial cells with few myofibrils that promotes the rapid conduction of the impulse through the ventricles. They are larger than the normal myocardial fibers.

What is Subendocardial injury?

Subendocardial infarction was defined as typical chest apin (greater than 15 minutes), serum enzyme elevation and persistent (greater than 48 hours) new T wave inversion and/or S-T segment depression in the absence of new pathologic Q waves.

What are the 3 layers of the heart and what is the function of each layer?

The heart wall is divided into three layers: epicardium, myocardium, and endocardium. Epicardium: the outer protective layer of the heart. Myocardium: muscular middle layer wall of the heart. Endocardium: the inner layer of the heart.

What are the 5 tissue layers of the heart?

Histologically, the heart is made of three layers of tissue: epicardium, myocardium, and endocardium….Layers of the heart.

Epicardium	Visceral layer of serous pericardium Comprised of mesothelial cells and fat and connective tissues
Myocardium	Muscle layer Comprised of cardiomyocytes

Why is Subendocardial layer prone to ischemia?

Subendocardial vulnerability to ischemia has been previously attributed to several mechanisms, namely, the greater subendocardial systolic compression was proposed to induce one or more of the following: 1) increased subendocardial vessel resistance (5, 36), 2) systolic backflow from endocardial to epicardial vessels ( …

What is Subendocardial myocardial infarction?

A subendocardial infarct results in necrosis exclusively inolving the innermost aspect of the myocardium. Usually a subendocardial infarct is the result of a partially occluded epicardial coronary artery (i.e. NSTEMI).

What causes Subendocardial myocardial infarction?

Regional infarcts are due to lack of blood flow that occurs when an epicardial artery is blocked by atheroma or thrombus, or other obstructions. Global subendocardial infarcts occur when there is lack of oxygenation despite circulation—for example, when there is a respiratory arrest followed by prolonged hypoxemia.

Which layers of the heart wall contains Purkinje fibers?

Which of these layers of the heart wall contains Purkinje fibers? The endocardium contains the Purkinje fibers and other parts of the cardiac electrical conduction system.

What is Subendocardial injury on ECG?

What is the myocardium made of?

The muscle layer of the heart is termed the myocardium and is made up of cardiomyocytes. The myocardium is found in the walls of all four chambers of the heart, though it is thicker in the ventricles and thinner in the atria.

What is the difference between myocardium endocardium and pericardium?

Furthermore, the myocardium is responsible for heart contractions while pericardium is responsible for the protection of the heart. Epicardium, myocardium, and endocardium are the three layers of the wall of the heart while pericardium is the membrane that surrounds the heart.

What type of tissue is the myocardium?

Cardiac muscle tissue, or myocardium, is a specialized type of muscle tissue that forms the heart. This muscle tissue, which contracts and releases involuntarily, is responsible for keeping the heart pumping blood around the body.

What tissue is myocardium made of?

cardiac muscle cells
The middle layer of the heart wall is the myocardium—the muscle tissue of the heart and the thickest layer of the heart wall. It is composed of cardiac muscle cells, or cardiomyocytes.

What is the subendocardial layer of the heart?

Subendocardial layer. It consists of a layer of loose fibrous tissue, containing the vessels and nerves of the conducting system of the heart. The purkinje fibres are located in this layer. As the subendocardial layer houses the conducting system of the heart, damage to this layer can result in various arrhythmias.

What is the structure of the myocardium?

The myocardium consists of cardiomyocytes grouped in strands also known as myofibres and the surrounding extracellular matrix with endomysial and perimysial components. The cardiomyocytes are linked with each other through distinctive junctional compounds, the intercalated discs, which facilitate intercellular electrical impulse conduction.

What are the two layers of the endocardium?

The endocardium has two layers. The inner layer lines the heart chambers and is made of endothelial cells. Superiorly, is the second layer: a subendocardial connective tissue which is continuous with the connective tissue of the myocardium. Branches of the heart’s conduction system are immersed into the subendocardial layer.

How is the outer border of the myocardium formed?

The outer border is formed by the subepicardial layer, which is interconnected to the epicardium, the latter consisting of a lining of mesothelial cells, a subserosal layer of connective tissue and a variable amount of epicardial fatty tissue. The arterial supply of the myocardium is provided by the coronary arteries.