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Smooth muscle is a type of non-striated muscle, found within the tunica media layer of arteries and veins, the bladder, uterus, male, female, and all animals, gastrointestinal tract, respiratory tract, the ciliary muscle and iris of the eye. The glomeruli of the kidneys contain a smooth muscle-like cell called the mesangial cell. Smooth muscle is fundamentally different from skeletal muscle and cardiac muscle in terms of structure, function, excitation-contraction coupling, and mechanism of contraction. Image File history File links Download high-resolution version (619x611, 136 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Smooth muscle ...
Image File history File links Download high-resolution version (619x611, 136 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Smooth muscle ...
Image File history File linksMetadata Illu_esophageal_layers. ...
Image File history File linksMetadata Illu_esophageal_layers. ...
The mucous membranes (or mucosa) are linings of ectodermic origin, covered in epithelium, that line various body cavities and internal organs. ...
In the gastrointestinal tract. ...
Muscularis can refer to: Muscularis mucosae Muscularis externa Category: ...
This article needs to be wikified. ...
Structure of a skeletal muscle Skeletal muscle is a type of striated muscle, attached to the skeleton. ...
Section of mucous membrane of human rectum. ...
The esophageal glands are small compound racemose glands of the mucous type: they are lodged in the submucous tissue, and each opens upon the surface by a long excretory duct. ...
Structure of a skeletal muscle Skeletal muscle is a type of striated muscle, attached to the skeleton. ...
The tunica media (or just media) is the middle layer of an artery. ...
Section of an artery An artery or arterial is also a class of highway. ...
In biology, a vein is a blood vessel which carries blood toward the heart. ...
This article is about the urinary bladder. ...
This article is about female reproductive anatomy. ...
Gut redirects here. ...
In humans the respiratory tract is the part of the anatomy that has to do with the process of respiration or breathing. ...
Glomerulus refers to two unrelated structures in the body, both named for their globular form. ...
Mesangial cells are specialized cells around blood vessels in the kidneys. ...
A top-down view of skeletal muscle Skeletal muscle is a type of striated muscle, usually attached to the skeleton. ...
Cardiac muscle is a type of involuntary striated muscle found within the heart. ...
Structure
Smooth muscle fibers are spindle-shaped, and, like all muscle, can contract and relax. In the relaxed state, each cell is spindle-shaped, 20-500 micrometers long, and 5 micrometers wide.[1] There are two types of smooth muscle arrangements in the body: multi-unit and single-unit. The single-unit type, also called unitary smooth muscle, is far more common. Whereas the former presents itself as distinct muscle fibers that are usually activated by their own nerve fibers, the latter operate as a single unit and are arranged in sheets or bundles. Unitary smooth muscle is also commonly referred to as visceral smooth muscle because it is found in the walls of the viscera, or internal organs, of the body, including the intestines, ducts such as the bile ducts, ureters and oviducts, and most blood vessels.[2] Unitary smooth muscle can be further divided into phasic and tonic. A top-down view of skeletal muscle A muscle contraction (also known as a muscle twitch or simply twitch) occurs when a muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. ...
An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ...
In anatomy, the viscera are the internal organs of an animal, in particular the internal organs of the head, thorax and abdomen. ...
The intestine is the portion of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. ...
A bile duct is any of a number of long tube-like structures that carry bile. ...
Transverse section of ureter. ...
In oviparous animals (those that lay eggs), the passage from the ovaries to the outside of the body is known as the oviduct. ...
The blood vessels are part of the circulatory system and function to transport blood throughout the body. ...
The cells that compose smooth muscle have, in general, single nuclei. The cells are arranged in sheets or bundles and connected by gap junctions. In order to contract, the cells contain actin filaments and a contractous protein called myosin. Whereas the filaments are essentially the same in smooth muscle as they are in skeletal and cardiac muscle, the way they are arranged is different. Some regulatory proteins also differ, and there are specific smooth muscle isoforms of actin and myosin. The smooth muscle cell contains less protein than a typical striated muscle cell and much less myosin. The actin content is similar, so the ratio of actin to myosin is ~6:1 in striated muscle and ~15:1 in smooth muscle. Smooth muscle does not contain the protein troponin, (calmodulin takes on the regulatory role in smooth muscle) and caldesmon and calponin are significant proteins expressed within smooth muscle. As non-striated muscle, the actin and myosin are not arranged into distinct sarcomeres that form orderly bands throughout the muscle cell. However, there is an organized cytoskeleton consisting of the intermediate filament proteins vimentin and desmin, along with actin filaments. Actin filaments attach to the sarcolemma by focal adhesions or attachment plaques and attach to other actin filaments via dense bodies (acting much like Z-lines in striated muscle). Evidence indicates that smooth muscle myosin is not bipolar with a central bare zone as in striated muscle, but is either side-polar or row-polar, and has no bare zone. Some smooth muscle preparations can be visualized contracting in a spiral corkscrew fashion, and contractile proteins can organize into zones of actin and myosin along the axis of the cell. HeLa cells stained for DNA with the Blue Hoechst dye. ...
A gap junction is a junction between certain animal/plant cell-types that allows different molecules and ions to pass freely between cells. ...
G-Actin (PDB code: 1j6z). ...
Myosin is a motor protein filament found in muscle tissue. ...
Troponin Troponin is a complex of three proteins that is integral to muscle contraction in skeletal and cardiac muscle, but not smooth muscle. ...
oommen sir is a fool. ...
Caldesmon is a calmodulin binding protein. ...
Image of sarcomere A sarcomere is the basic unit of a cross striated muscles myofibril. ...
The sarcolemma possess microdomains specialized to cell-signaling events and ion channels called caveolae. These invaginations in the sarcoplasma contain a host of receptors (prostacyclin, endothelin, serotonin, muscarinic receptors, adrenergic receptors), second messenger generators (adenylate cyclase, Phospholipase C), G proteins (RhoA, G alpha), kinases (rho kinase-ROCK, Protein kinase C, Protein Kinase A), ion channels (L type Calcium channels, ATP sensitive Potassium channels, Calcium sensitive Potassium channels) in close proximity. The caveolae are often in close proximity to sarcoplasmic reticulum or mitochondria, and have been proposed to organize signaling molecules in the membrane. In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ...
Prostacyclin is a member of the family of lipid molecules known as eicosanoids. ...
Endothelin is a 21-amino acid vasoconstricting peptide that plays a key part in vascular homeostasis. ...
For the professional wrestling stable, see Ravens Nest#Serotonin. ...
In biology, second messengers are low-weight diffusible molecules that are used in signal transduction to relay signals within a cell. ...
Ion channels are present in the membranes that surround all biological cells. ...
Function To maintain organ dimensions against forces, cells are fastened to one another adherens junctions. As a consequence, cells are mechanically coupled to one another such that contraction of one cell invokes some degree of contraction in an adjoining cell. Gap junctions couple adjacent cells chemically and electrically, facilitating the spread of chemicals (e.g., calcium) or action potentials between smooth muscle cells. Smooth muscle may contract spontaneously (via ionic channel dynamic or Cajal pacemaker cells) or be induced by a number of physiochemical agents (e.g., hormones, drugs, neurotransmitters - particularly from the autonomic nervous system), and also mechanical stimulation (such as stretch). Principal interactions of structural proteins at cadherin-based adherens junction. ...
This article or section is in need of attention from an expert on the subject. ...
Smooth muscles have been divided into "multi-unit" and "visceral" types or into "phasic" and "tonic" types based on the characteristics of the contractile patterns. It may contract phasically with rapid contraction and relaxation, or tonically with slow and sustained contraction. The reproductive, digestive, respiratory, and urinary tracts, skin, eye, and vasculature all contain this tonic muscle type. For example, contractile function of vascular smooth muscle is critical to regulating the lumenal diameter of the small arteries-arterioles called resistance vessels. The resistance arteries contribute significantly to setting the level of blood pressure. Smooth muscle contracts slowly and may maintain the contraction (tonically) for prolonged periods in blood vessels, bronchioles, and some sphincters. In the digestive tract, smooth muscle contracts in a rhythmic peristaltic fashion, rhythmically forcing foodstuffs through the digestive tract as the result of phasic contraction. Peristalsis is the process of involuntary wave-like successive muscular contractions by which food is moved through the digestive tract. ...
Smooth muscle in various regions of the vascular tree, the airway and lungs, kidneys, etc. is different in their expression of ionic channels, hormone receptors, cell-signaling pathways, and other proteins that determine function. Smooth muscle-containing tissue often must be stretched, so elasticity is an important attribute of smooth muscle. Smooth muscle cells may secrete a complex extracellular matrix containing collagen (predominantly types I and III), elastin, glycoproteins, and proteoglycans. These fibers with their extracellular matrices contribute to the viscoelasticity of these tissues. Smooth muscle also has specific elastin and collagen receptors to interact with these proteins. Tropocollagen triple helix. ...
Elastin is a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting. ...
A glycoprotein is a macromolecule composed of a protein and a carbohydrate (a sugar). ...
Proteoglycans represent a special class of glycoprotein that are heavily glycosylated. ...
Viscoelasticity, also known as anelasticity, describes materials that exhibit both viscous and elastic characteristics when undergoing plastic deformation. ...
Contraction and relaxation basics Smooth muscle contraction is caused by the sliding of myosin and actin filaments (a sliding filament mechanism) over each other. The energy for this to happen is provided by the hydrolysis of ATP. Myosin functions as an ATPase utilizing ATP to produce a molecular conformational change of part of the myosin and produces movement. Movement of the filaments over each other happens when the globular heads protruding from myosin filaments attach and interact with actin filaments to form crossbridges. The myosin heads tilt and drag along the actin filament a small distance (10-12 nm). The heads then release the actin filament and adopt their original conformation. They can then re-bind to another part of the actin molecule and drag it along further. This process is called crossbridge cycling and is the same for all muscles (see muscle contraction). Unlike cardiac and skeletal muscle, smooth muscle does not contain the calcium-binding protein troponin. Contraction is initiated by a calcium-regulated phosphorylation of myosin, rather than a calcium-activated troponin system. Myosin is a motor protein filament found in muscle tissue. ...
G-Actin (PDB code: 1j6z). ...
Hydrolysis is a chemical reaction or process in which a chemical compound is broken down by reaction with water. ...
Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ...
A top-down view of skeletal muscle A muscle contraction (also known as a muscle twitch or simply twitch) occurs when a muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. ...
Crossbridge cycling cannot occur until the myosin heads have been activated to allow crossbridges to form. The myosin heads are made up of heavy chains and light protein chains. When the light chains are phosphorylated, they become active and will allow contraction to occur. The enzyme that phosphorylates the light chains is called myosin light-chain kinase (MLCK). In order to control contraction, MLCK will work only when the muscle is stimulated to contract. Stimulation will increase the intracellular concentration of calcium ions. These bind to a molecule called calmodulin, and form a calcium-calmodulin complex. It is this complex that will bind to MLCK to activate it, allowing the chain of reactions for contraction to occur. The phosphorylation of the light chains by MLCK is countered by a myosin light-chain phosphatase, which dephosphorylates the myosin light chains and inhibits the contraction. Other signaling pathways have also been implicated in the regulation actin and myosin dynamics. In general, the relaxation of smooth muscle is by cell-signaling pathways that increase the myosin phosphatase activity, decrease the intracellular calcium levels, hyperpolarize the smooth muscle, and/or regulate actin and myosin dynamics. Myosin-light-chain kinase (MLCK) is a serine/threonine-specific protein kinase which phosphorylates myosin. ...
oommen sir is a fool. ...
Invertebrate smooth muscle In invertebrate smooth muscle, contraction is initiated with the binding of calcium directly to myosin and then rapidly cycling cross-bridges, generating force. Similar to the mechanism of vertebrate smooth muscle, there is a low calcium and low energy utilization catch phase. This sustained phase or catch phase has been attributed to a catch protein that has similarities to myosin light-chain kinase and the elastic protein-titin called twitchin. Mollusk-like clams use this catch phase of smooth muscle to keep their shell closed for prolonged periods with little energy usage.
Control Smooth muscle cells can be stimulated to contract or relax in many different ways. They may be directly stimulated by the autonomic nervous system ("involuntarily" control), but can also react on stimuli from neighbouring cells and on hormones (vasodilators or vasoconstrictor) within the medium that it carries. This article or section is in need of attention from an expert on the subject. ...
For other uses, see Volunteer (disambiguation). ...
A vasodilator is a substance that causes blood vessels in the body to become wider by relaxing the smooth muscle in the vessel wall, or vasodilation. ...
A vasoconstrictor, also vasopressor or simply pressor, is any substance that acts to cause vasoconstriction (narrowing of the lumena of blood vessels) and usually results in an increase of the blood pressure. ...
Growth and rearrangement The mechanism in which external factors stimulate growth and rearrangement is not yet fully understood. A number of growth factors and neurohumoral agents influence smooth muscle growth and differentiation. The Notch receptor and cell-signaling pathway have been demonstrated to be essential to vasculogenesis and the formation of arteries and veins.
The embryological origin of smooth muscle is usually of mesodermal origin. However, the smooth muscle within the Aorta and Pulmonary arteries (the Great Arteries of the heart) is derived from ectomesenchyme of neural crest origin, although coronary artery smooth muscle is of mesodermal origin.
Related diseases "Smooth muscle condition" is a condition in which the body of a developing embryo does not create enough smooth muscle for the gastrointestinal system. This condition is fatal. For the Physics term GUT, please refer to Grand unification theory The gastrointestinal or digestive tract, also referred to as the GI tract or the alimentary canal or the gut, is the system of organs within multicellular animals which takes in food, digests it to extract energy and nutrients, and...
Anti-smooth muscle antibodies (ASMA) can be a symptom of an auto-immune disorder, such as hepatitis, cirrhosis, or lupus. Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. ...
Hepatitis (plural hepatitides) implies injury to liver characterised by presence of inflammatory cells in the liver tissue. ...
Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrotic scar tissue as well as regenerative nodules, leading to progressive loss of liver function. ...
Systemic Lupus Erythematosus (SLE or lupus) is a chronic autoimmune disease that can be fatal, though with recent medical advances, fatalities are becoming increasingly rare. ...
Vascular smooth muscle tumors are very rare. They can be malignant or benign, and morbidity can be significant with either type. Intravascular leiomyomatosis is a benign neoplasm that extends through the veins; angioleiomyoma is a benign neoplasm of the extremities; vascular leiomyosarcomas is a malign neoplasm that can be found in the inferior vena cava, pulmonary arteries and veins, and other peripheral vessels.
See Atherosclerosis.
References - ^ Textbook of Medical Physiology, 11th Ed., Elsevier 2006, page 92.
- ^ Textbook of Medical Physiology, 11th Ed., Elsevier 2006, page 93.
See also A top-down view of skeletal muscle Skeletal muscle is a type of striated muscle, usually attached to the skeleton. ...
Cardiac muscle is a type of involuntary striated muscle found within the heart. ...
Vascular smooth muscle refers to the particular type of smooth muscle found within, and composing the majority of the wall of blood vessels. ...
External links | Histology: muscle tissue | | skeletal muscle/general | epimysium, fascicle, perimysium, endomysium, muscle fiber (intrafusal, extrafusal), myofibril sarcomere (a, i, and h bands; z and m lines), myofilaments (thin filament/actin, thick filament/myosin, elastic filament/titin, nebulin), tropomyosin, troponin (T, C, I) The College of Medicine at Urbana-Champaign is a graduate school at the University of Illinois at Urbana-Champaign. ...
The University of Kansas (often referred to as KU or just Kansas) is an institution of higher learning in Lawrence, Kansas. ...
For the similarly named institution in Chestnut Hill, see Boston College. ...
In 1828 the Medical Academy of Georgia was chartered by the state of Georgia with plans to offer a single course of lectures leading to a bachelors degree. ...
The muscular system is the anatomical system of a species that allows it to move. ...
For other uses of Muscles, see Muscles (disambiguation). ...
A top-down view of skeletal muscle A muscle contraction (also known as a muscle twitch or simply twitch) occurs when a muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. ...
This is a list of muscles of the human anatomy. ...
For other uses of Muscles, see Muscles (disambiguation). ...
Cardiac muscle is a type of involuntary striated muscle found within the heart. ...
A top-down view of skeletal muscle Skeletal muscle is a type of striated muscle, usually attached to the skeleton. ...
A thin section of lung tissue stained with hematoxylin and eosin. ...
For other uses of Muscles, see Muscles (disambiguation). ...
A top-down view of skeletal muscle Skeletal muscle is a type of striated muscle, usually attached to the skeleton. ...
Epimysium is a layer of connective tissue which ensheaths the entire muscle. ...
In anatomy, a fascicle is a bundle of skeletal muscle fibers surrounded by connective tissue. ...
Perimysium is a sheath of connective tissue which groups individual muscle fibers ( anywhere between 10 to 100 or more) into bundles or fascicles Endomysium Histology at cytochemistry. ...
The endomysium, literally meaning within the muscle, is a layer of connective tissue that ensheaths a muscle fiber and is composed mostly from reticular fibers. ...
A simplified, global view of a neuromuscular junction: 1. ...
Intrafusal fibers are muscle fibers that comprise the muscle spindle. ...
Extrafusal muscle fibers are a class of muscle fiber innervated by alpha motor neurons. ...
A diagram of the structure of a Myofybril Myofibrils (obsolete term: sarcostyles) are cylindrical organelles, found within muscle cells. ...
Image of sarcomere A sarcomere is the basic unit of a cross striated muscles myofibril. ...
See sarcomere. ...
G-Actin (PDB code: 1j6z). ...
Myosin is a motor protein filament found in muscle tissue. ...
Not to be confused with Tintin. ...
Nebulin is an actin-binding molecule which is localized to the I-band in skeletal muscle. ...
Troponin Tropomyosin, along with the troponin, regulate the shortening of the muscle protein filaments actin and myosin. ...
Troponin Troponin is a complex of three proteins that is integral to muscle contraction in skeletal and cardiac muscle, but not smooth muscle. ...
Troponin Troponin T is a part of the troponin complex. ...
Troponin Troponin C is a part of the troponin complex. ...
Troponin Troponin I is a part of the troponin complex. ...
costamere (dystrophin, α,β-dystrobrevin, syncoilin, synemin/desmuslin, dysbindin, sarcoglycan, dystroglycan, sarcospan), desmin The costamere is a structural-functional component of skeletal muscle cells which, according to original descriptions in the early 1980s (which are generally still accepted), are sub-sarcolemmal protein assemblies circumferentially aligned in register with the Z-disk of peripheral myofibrils. ...
Dystrophin is a protein found in membranes surrounding individual muscle fibers, and its deficiency is one of the root causes of muscular dystrophy. ...
Dystrobrevin is a protein that binds to dystrophin in the costamere of skeletal muscle cells. ...
Syncoilin is a muscle-specific intermediate filament, first isolated by Newey and colleagues[1] as a binding partner to α-dystrobrevin, as determined by a yeast two-hybrid assay. ...
Synemin, also called desmuslin, is an intermediate filament (IF) and, like other IFs, primarily functions to integrate mechanical stress and maintain structural integrity in eukaryotic cells. ...
Dysbindin, short for dystrobrevin-binding protein 1, is a protein constituent of the dystrophin-associated protein complex of skeletal muscle cells. ...
The sarcoglcyans are a family of five transmembrane proteins (α, β, γ, δ or ε) involved in the protein complex responsible for connecting the muscle fibre cytoskeleton to the extracellular matrix, preventing damage the muscle fibre sarcolemma through shearing forces. ...
Dystroglycan is a protein of the cytoskeleton involved in joining dystrophin and laminin. ...
Sarcospan, discovered by the research group of Kevin Campbell, is a 25-kDa transmembrane protein located in the dystrophin-associated protein complex of skeletal muscle cells. ...
Intermediate filaments are one component of the cytoskeleton - important structural components of living cells. ...
neuromuscular junction, motor unit, muscle spindle, excitation-contraction coupling, sliding filament mechanism A neuromuscular junction is the junction of the axon terminal of a motoneuron with the motor end plate, the highly-excitable region of muscle fiber plasma membrane responsible for initiation of action potentials across the muscles surface. ...
A motor unit is a group of cells under the control of a single motor neuron; groups of motor units work together, as a single muscle. ...
A muscle spindle is a specialized muscle structure innervated by both sensory and motor neuron axons. ...
// Excitation-contraction (EC) coupling is a term coined in 1952 to describe the physiological process of converting an electrical stimulus to mechanical response [1]. This process is fundamental to muscle physiology, whereby the electrical stimulus is usually an action potential and the mechanical response is contraction. ...
The sliding filament mechanism is a process used by muscles to contract. ...
myoblast, satellite cell, sarcoplasm, sarcolemma, sarcoplasmic reticulum, T-tubule | | cardiac muscle | myocardium, intercalated disc, nebulette | | smooth muscle | calmodulin, vascular smooth muscle | Myoblasts are a type of stem cells that exist in muscles. ...
Satellite cells are found in the mature muscle around the muscle fibres, and differentiate from myoblasts. ...
The Sarcoplasm of a muscle fiber is comparable to the cytoplasm of other cells, but it houses unusually large amounts of glycosomes (granules of stored glycogen) and significant amounts of myoglobin, an oxygen binding protein. ...
Muscle system The sarcolemma is the cell membrane of a muscle cell. ...
The endoplasmic reticulum or ER is an organelle found in all eukaryotic cells that is an interconnected network of tubules, vesicles and cisternae that is responsible for several specialized functions: Protein translation, folding, and transport of proteins to be used in the cell membrane (e. ...
A T-tubule (or Transverse tubule), is a deep invagination of the plasma membrane found in skeletal and cardiac muscle cells. ...
Cardiac muscle is a type of involuntary striated muscle found within the heart. ...
Myocardium is the muscular tissue of the heart. ...
An intercalated disc is an undulating double membrane separating adjacent cells in cardiac muscle fibers. ...
Nebulette is an isoform of the protein nebulin. ...
oommen sir is a fool. ...
Vascular smooth muscle refers to the particular type of smooth muscle found within, and composing the majority of the wall of blood vessels. ...
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