What is myocyte necrosis?

Contraction band necrosis is a type of uncontrolled cell death (necrosis) unique to cardiac myocytes and thought to arise in reperfusion from hypercontraction, which results in sarcolemmal rupture. It is a characteristic histologic finding of a recent myocardial infarction (heart attack) that was partially reperfused.

What causes coagulation necrosis?

Coagulative necrosis is most commonly caused by conditions that do not involve severe trauma, toxins or an acute or chronic immune response. The lack of oxygen (hypoxia) causes cell death in a localized area which is perfused by blood vessels failing to deliver primarily oxygen, but also other important nutrients.

What is cardiac myocyte?

Cardiac myocytes form a three-dimensional syncytium that enables propagation of electrical signals across specialized intracellular junctions to produce coordinated mechanical contractions that pump blood forward (Severs, 2000).

What is a cardiac sarcomere?

The sarcomere is defined as the region of myofilament structures between two Z-lines. The distance between Z-lines (i.e., sarcomere length) ranges from about 1.6 to 2.2 μ in human hearts. The sarcomere is composed of thick and thin filaments – myosin and actin, respectively.

What are two types of cardiac myocytes?

There are two major types of cardiac muscle cells: myocardial contractile cells and myocardial conducting cells.

What is the function of the cytoskeleton in cardiac myocytes?

In cardiac myocytes this forms a scalloped surface. The cytoskeleton is what the rest of the cell builds off of and has two primary purposes; the first is to stabilize the topography of the intracellular components and the second is to help control the size and shape of the cell.

How are cardiomyocytes and smooth muscle cells related?

Cardiomyocytes are the muscle fibres that form the chambers of the heart, and have a single central nucleus. Skeletal muscle fibers help support and move the body and tend to have peripheral nuclei. Smooth muscle cells control involuntary movements such as the peristalsis contractions in the oesophagus and stomach.

How does excitation of a myocyte trigger action potential?

Excitation of a myocyte causes depolarization at its synapses, the neuromuscular junctions, which triggers action potential. With a singular neuromuscular junction, each muscle fiber receives input from just one somatic efferent neuron. Action potential in a somatic efferent neuron causes the release of the neurotransmitter acetylcholine.

What causes progressive myocardial dystrophy in a mouse?

Myocyte necrosis underlies progressive myocardial dystrophy in mouse dsg2-related arrhythmogenic right ventricular cardiomyopathy Mutations in the cardiac desmosomal protein desmoglein-2 (DSG2) are associated with arrhythmogenic right ventricular cardiomyopathy (ARVC).