What is a myocyte in heart?
The cardiac myocyte is a specialized muscle cell that is approximately 25 μ in diameter and about 100 μ in length. The myocyte is composed of bundles of myofibrils that contain myofilaments (Figure 1). The interactions between actin and myosin serve as the basis for the sliding filament theory of muscle contraction.
What do myocyte cells do?
The muscle myocyte is a cell that has differentiated for the specialized function of contraction. Although cardiac, skeletal, and smooth muscle cells share much common functionality, they do not all share identical features, anatomical structures, or mechanisms of contraction.
How long do cardiac myocytes live?
During an average life span, fewer than 50% of cardiomyocytes renew. Remarkably, despite the substantial functional and metabolic demands placed on cardiomyocytes during the course of a lifetime, some of these cells survive for more than half a century.
Why is myocyte important?
Myocyte mitochondria provide high-energy phosphate molecules that fuel calcium and other ion pumps, sarcomere contraction and relaxation, maintenance of the resting cell membrane potential, and propagation of the cardiac action potential.
What is myocyte damage?
Myocyte damage and loss of myofibers is the potential mechanism of iron overload toxicity in congestive cardiac failure in thalassemia. Complete reversal of the cardiomyopathy and normalization of iron load by deferiprone. Hemoglobin.
What causes myocyte death?
Chronic hypoxia in the presence of high glucose leads to progressive acidosis of cardiac myocytes in culture. The condition parallels myocardial ischemia in vivo, where ischemic tissue becomes rapidly hypoxic and acidotic.
What does a myocyte contain?
Myocytes contain one or two nuclei that are centrally located and oblong. Myofibrils course around the nucleus, leaving at the nuclear poles a conical area free of contractile elements but densely packed with other cellular organelles.
What is the structure of a myocyte?
A specialized structure of the myocyte is the sarcolemma, a coalescence of the plasma membrane proper and the basement membrane. Interwoven throughout the sarcolemma are integrins, which, with receptor transmembrane proteins, bind the myocyte to the extracellular matrix and basement membrane.
What happens to myocytes in heart failure?
Structural remodeling of the heart reflects changes in myocyte morphology. Disproportional myocyte growth is observed in pathologic concentric hypertrophy (myocyte thickening) and in eccentric dilated hypertrophy (myocyte lengthening). Alterations in myocyte shape lead to changes in chamber geometry and wall stress.
What is a myocyte called?
A muscle cell is also known as a myocyte when referring to either a cardiac muscle cell (cardiomyocyte), or a smooth muscle cell as these are both small cells. A skeletal muscle cell is long and threadlike with many nuclei and is called a muscle fiber.
Where are myocyte cells located?
Skeletal muscle cells, and cardiac muscle cells contain myofibrils and sarcomeres and form a striated muscle tissue….
|General structure of a skeletal muscle cell and neuromuscular junction: Axon Neuromuscular junction Skeletal muscle fiber Myofibril|
What do myocytes look like?
What is the main function of cardiac cells?
As the chief cell type of the heart, cardiac cells are primarily involved in the contractile function of the heart that enables the pumping of blood around the body.
What are the characteristics of cardiac cells?
Cardiac muscle cells are found only in the heart, and are specialized to pump blood powerfully and efficiently throughout our entire lifetime. Four characteristics define cardiac muscle tissue cells: they are involuntary and intrinsically controlled, striated, branched, and single nucleated.
Can a cardiac cell regenerate itself?
Conventional wisdom states that the heart cannot regenerate because cardiac myocytes – unlike cells in the bone marrow or intestinal epithelium – cannot divide.
What is the name of the cells found in the myocardium?
The myocardium is mainly made up of two types of cells: cardiomyocytes and fibroblasts. Fibroblasts are distributed between cardiomyocytes, along with extracellular matrix (ECM), blood vessels, lymphatic vessels, and nerve endings. The ECM contains fibrillar collagen network, proteoglycans, glycosaminoglycans, and the basement membrane.