cardiac muscle

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Related to Cardiac muscle cell: smooth muscle cell, skeletal muscle cell

car·di·ac mus·cle

the involuntary muscle comprising the myocardium and walls of the pulmonary veins and superior vena cava, consisting of anastomosing transversely striated muscle fibers formed of cells united at intercalated discs; the one or two nuclei of each cell are centrally located and the longitudinally arranged myofibrils have considerable sarcoplasm around them; connective tissue is limited to reticular and fine collagenous fibers; contraction is rhythmic and intrinsically stimulated.
Synonym(s): muscle of heart

cardiac muscle

n.
The specialized striated muscle tissue of the heart; the myocardium.

cardiac muscle

a special striated muscle of the myocardium, containing dark intercalated disks at the junctions of abutting fibers. Cardiac muscle is an exception among involuntary muscles, which are characteristically smooth. Its contractile fibers resemble those of skeletal muscle but are only one third as large in diameter, are richer in sarcoplasm, and contain centrally located instead of peripheral nuclei. Compare smooth muscle, striated muscle.
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Cardiac muscle

car·di·ac mus·cle

(kahr'dē-ak mŭs'ĕl)
The muscle forming the myocardium, consisting of anastomosing transversely striated muscle fibers formed of cells united at intercalated discs.
Synonym(s): muscle of heart.
Cardiac muscleclick for a larger image
Fig. 91 Cardiac muscle . The intercalated discs enable the rapid transmission of excitatory waves across the tissue.

cardiac muscle

a type of vertebrate muscle found only in the HEART, which appears to be halfway between INVOLUNTARY MUSCLE and STRIATED MUSCLE in that its fibres are striated, but contain a single nucleus (see Fig. 91 ). The action of cardiac fibres is to produce strong and rhythmic contractions from within, even when removed from the body (see MYOGENIC CONTRACTION). Unlike striated muscle, cardiac muscle does not become fatigued even though it is repeatedly stimulated. The heartbeat is controlled by the AUTONOMIC NERVOUS SYSTEM.
Figure 1: Muscles of the back.
Figure 2: Muscles of the abdominal wall. Superficial layer shown on the right side of the body, deeper layer on the left.
Figure 3: Muscles of the shoulder girdle and upper limb.
Figure 4: Muscles of the shoulder girdle and upper limb.
Figure 5: Muscles of the lower limb. Left leg from the front.
Figure 6: Muscles of the lower limb. Left leg from the back.
Figure 7: Structure of skeletal muscle at progressively higher magnification, from whole muscle to contractile proteins (A-D, F). E represents the 'sliding filaments' diagrammatically.

muscle

contractile soft tissue, responsible for all significant active movements and force-generations in an animal body. Divisible into three classes: (1) skeletal or voluntary muscle the class of muscle acting, in almost all body locations, to move one bone relative to another, the more superficial skeletal muscles being visible under the skin in all but the most obese subjects; (2) cardiac muscle the type unique to the heart; (3) smooth muscle composing the actively adjustable components of the walls of blood vessels and of the gastrointestinal, respiratory, urinary and reproductive tracts. Skeletal and cardiac are the striated muscles; cardiac and smooth share the property of being involuntary. See also muscle fibres, muscle fibre types, myofibrils; Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7.

muscle

an organ composed of bundles of fibers that has the power to contract and hence to produce movement. Muscles are responsible for locomotion and help support the body, generate heat and perform a number of other functions. They are of two varieties: striated (or striped, voluntary or skeletal), which makes up most of the meat of a carcass, and smooth (unstriated), which includes all the involuntary muscle of the viscera, heart and blood vessels.
Skeletal muscle fibers range in length from a few millimeters to many centimeters. They also vary in color from white to deep red. Each muscle fiber receives its own nerve impulses, which trigger fine and varied motions. At the signal of an impulse traveling down the nerve, the muscle fiber changes chemical energy into mechanical energy, and the result is muscle contraction. At least two major types of muscle fiber have been identified by histochemical techniques: type I (red) fibers, which have a slow contraction; and type II (white) fibers, which have a fast contraction.
Some muscles are attached to bones by tendons. Others are attached to other muscles, and to skin, producing, for example, the skin twitch, the eye blink and hair erection. Parts of the walls of hollow internal organs, such as the heart, stomach and intestines and also blood vessels, are composed of muscles. See also muscular. For a complete list of named muscles see Table 13.

agonistic muscle
prime mover; a muscle opposed in action by another muscle, called the antagonist.
antagonistic muscle
one that counteracts the action of another muscle (the agonist).
appendicular muscle
one of the muscles of a limb.
arrector pili muscle
small, smooth muscle attached to the bulb of the hair which causes erection of the hair and compression of the attending sebaceous gland when it contracts.
arterial muscle
part of the tunica media; smooth muscle fibers arranged in a circular pattern around the lumen.
articular muscle
one that has one end attached to the capsule of a joint.
axial muscle
1. muscles derived from the somites in the embryo.
2. the muscles around the vertebral column.
muscle biopsy
sample of living muscle obtained by excision or punch.
cardiac muscle
striated involuntary muscle with branched fibers and containing modified fibers which act as cardiac conducting cells.
congenital muscle defects
may be environmental, e.g. nutritional muscular dystrophy, or inherited, e.g. splayleg of piglets.
congenital type II muscle fiber hypertrophy
occurs in the hip joint musculature in German shepherd dogs but there is no detectable abnormality of gait.
cutaneous muscle
striated muscle that inserts into the skin.
double muscle
see myofiber hyperplasia.
esophageal muscle
the tunica muscularis of the esophagus in most domestic animals is mostly striated; in pigs, horses and cats there are small segments of smooth muscle; in birds the entire tunic is smooth muscle.
extraocular m's
the six or seven voluntary muscles that move the eyeball: dorsal, ventral, medial and lateral recti, dorsal and ventral oblique, and retractor bulbi muscles.
extrinsic muscle
one that originates in another part than that of its insertion, e.g. those originating outside the eye, which move the eyeball.
fast-twitch skeletal muscle
two of the three types of skeletal muscle are pale in color and fast-twitch—type IIa (fast-twitch oxidative-glycolytic), type IIb (fast-twitch glycolytic). Type IIa fibers are fatigue-resistant, type IIb fatigue easily.
muscle fiber
see muscle (above).
fixation m's, fixator m's
accessory muscles that serve to steady a part.
hamstring m's
the biceps, semimembranosus and semitendinosus muscles. See also hamstring.
intraocular m's
the intrinsic muscles of the eyeball.
intrinsic muscle
one whose origin and insertion are both in the same part or organ, such as those entirely within the eye.
involuntary muscle
see smooth muscle (below).
iridial muscle
layers of circular (sphincter) and radial (dilator) muscles. See also iris.
jaw muscle
see Table 13.1H muscles of mastication.
laryngeal muscle
see Table 13.1E muscles of the larynx.
limb muscle
see Table 13.3, 13.4 muscles of the fore- and hindlimbs.
masseter muscle
the principal muscle of mastication. See also Table 13.1H.
mylohyoid muscle
see Table 13.1D muscles of the hyoid apparatus.
muscle neoplasms
of striated muscle—rhabdomyoma, rhabdomyosarcoma; of plain muscle—leiomyoma, leiomyosarcoma.
muscle nonstriated
see smooth muscle (below).
orbicular muscle
one that encircles a body opening, e.g. the eye or mouth.
muscle-paralyzing drugs
drugs which produce neuromuscular blockade, used as muscle relaxants during surgical procedures. Include d-tubocurarine, alcuronium chloride, pancuronium, vecuronium, atracurium besylate, succinylcholine.
red muscle
type 1 fibers predominate with slow contraction cycles and aerobic metabolism.
muscle rupture
the muscle may have torn away from its insertion, in which case the tendon will be slack, or it may be a complete or partial separation of the belly of the muscle, when the muscle will be swollen and hard. Structural and conformational changes may result, e.g. in rupture of the gastrocnemius muscle, and the hernias caused by rupture of the ventral abdominal muscles or the diaphragm.
skeletal m's
striated muscles that are attached to bones and typically cross at least one joint. Called also voluntary or striated muscles.
slow-twitch skeletal muscle
type 1 skeletal muscle fibers are bright red and contain large amounts of myoglobin; not easily fatigued.
smooth muscle
plain or involuntary muscle which powers the internal organs and is controlled by the autonomic nervous system; slow contracting cycles and fatigue resistant. Two types listed, visceral and vascular.
sphincter muscle
a ringlike muscle that closes a natural orifice; called also sphincter.
muscle spindle
sensory end-organ attached to the perimysial connective tissue of the muscle.
muscle strain
soreness and stiffness in a muscle due to overexertion or contusion, especially in muscles that have not been conditioned for hard use; some of the muscle fibers may actually tear.
striated muscle
see skeletal muscles (above).
synergic m's
those that assist one another in action.
temporal muscle
a significant muscle of mastication. See also Table 13.1H.
muscle-tendon junction
the union between connective tissue investing muscles and anchoring connective tissue.
type I muscle fiber
see slow-twitch skeletal muscle (above).
type II muscle fiber
see fast-twitch skeletal muscle (above).
type II muscle fiber deficiency
a relative deficiency of type II muscle fibers, with a predominance of type I fibers. An inherited defect in Labrador retrievers. Clinical signs include stunted growth, and muscle weakness and abnormal gait, which subside with rest, from an early age.
voluntary muscle
see skeletal muscle (above).
white muscle
consist of type II fibers; fast contraction fibers and aerobic metabolism are characteristic.
yoked m's
those that normally act simultaneously and equally, as in moving the eyes.
References in periodicals archive ?
Grafts of human cardiac muscle cells, grown from embryonic stem cells, coupled electrically and contracted synchronously with host muscle following transplantation in guinea pig hearts.
Cardionogen treatment enlarged the zebrafish heart by stimulating production of new cardiac muscle cells from stem cells.
Experiments have already been carried out with many different materials that could provide a scaffold substance for the loading of cardiac muscle cells.
A group led by Teruo Okano, a professor of regenerative medicine at Tokyo Women's Medical University, and Yoshiki Sawa, a cardiovascular surgeon at Osaka University, successfully cultivated newborn rats' cells to form a sheet of cardiac muscle and used the sheet to strengthen the functions of the rat's heart, whose cardiac muscle cells had died.
During a heart attack, or acute myocardial infarction (AMI), cardiac muscle cells (myocytes) die due to blockage of the coronary artery that normally supplies them with oxygen-rich blood.
The research team also confirmed previous reports that T4 activates the Akt survival kinase and protects cardiac muscle cells from apoptosis (programmed cell death), that the infarct sizes were smaller and cardiac function significantly improved in mice receiving T4, and that T4-treated mice had a significant reduction in cardiac fibrosis (scarring) due to the reduction of collagen expression.
Gene therapy has been found to improve contractile function in isolated cardiac muscle cells obtained from patients in heart failure, according to a report published in the December 7 issue of Circulation.
Because stem cells are immature cells they have the potential to develop into new blood vessels and preserve cardiac muscle cells.
Using calcium imaging with the MetaMorph ICS, the reaction of cardiac muscle cells can be analyzed in real-time, giving researchers important clues as to how the cardiac muscle works.
Among its initiatives, Coriell scientists are investigating the viability and growth of islet cells, which may hold therapeutic options for patients with diabetes; the potential uses of adipose (fat) stem cells in the repair of damaged tissue; the nervous system and understanding of how stem cells may participate in the development or regeneration of the brain or spinal cord following injury; and the capacity to transform umbilical cord blood stem cells into and replace cardiac muscle cells.
Specifically, the team found that their intervention halted transforming growth factor beta (TGF-beta) secretion at a precise location called cell receptor type 2 in cardiac muscle cells.
CHF and its inhibition by oxypurinol may prevent oxidant damage and sensitize cardiac muscle cells to intracellular calcium, leading to improved cardiac oxygen-use efficiency.