cardiac muscle


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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.

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.
References in periodicals archive ?
To observe changes in cardiac muscle mitochondrial biogenesis, levels of the marker proteins cytochrome c and succinate dehydrogenase were measured.
Effects of AE and RS, Alone and Combined, on Exhaustive Exercise-Induced Skeletal and Cardiac Muscle Damage and the Underlying Mechanism
The present clinical randomized controlled trial explored the protective effect of perioperative simvastatin on cardiac muscle after CPB and the relationship of such effects to cardiomyocyte autophagy.
This means that the cardiac muscle of the left ventricle must be thicker than the cardiac muscle of the right ventricular wall as it has to be able to develop and exert a greater force to overcome the corresponding higher pressures in the aorta.
The study concluded that water-pipe smoke induces structural changes in the heart ventricle tissues, causing a negative impact on the capacity of the cardiac muscle for pumping blood and may lead to heart attack due to accumulation of free radicals and tissue inflammation.
Cardiac muscle can contract in a rhythmic manner without any direct stimulus from the nervous system.
Troponin I has found to increase in acute myocardial infarction after 3- 6 hours of the onset of chest pain, peak in about 12 hours and remain elevated for 3-10 days because of continuous release of myofilament components from the injured cardiac muscle. [6-8] Hence, minor myocardial injury is easily detectable by measuring cardiac troponin I but not by other conventional cardiac markers like creatine kinase and LDH.
"Because we can't replace lost cardiac muscle, the condition irreversibly leads to a decline in heart function and ultimately death.
Compared with a healthy hawk, concentrations were elevated by a factor of 50 in the kidneys, 37 in skeletal muscle, and 18 in cardiac muscle.
Changes in other markers suggested that PE may inhibit collage hyperplasia, lessen the interstitial fibrosis of cardiac muscle and increase compliance of cardiac muscle to improve the heart's diastolic function in AMI rats.
For this purpose, we evaluated the influence of DOX administration alone and in a combined therapy with CAR on the hemodynamic parameters and on the degree of cardiac muscle cell alterations in rabbits.
The cells gradually take on the characteristics of cardiac muscle over the course of several weeks, as they turn into fully reprogrammed, beating heart cells.