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Information about Myocardium

Arterycoronary arteries
Dorlands/Elsevier m_24/12554874
Myocardium is the muscular tissue of the heart.

Relationship to other layers

The other tissues of the heart are:

Composition

The myocardium is composed of specialized cardiac muscle cells with an ability not possessed by muscle tissue elsewhere in the body. Cardiac muscle, like other muscles, can contract, but it can also carry an action potential (i.e. conduct electricity), like the neurones that constitute nerves.

The blood supply of the myocardium is by the coronary arteries. The myocardium is subject to two opposed electrical subsets of control. First order electrical control of the myocardium is derived from the sinoatrial node. Propagation of first order control from the sinoatrial node is closely tied to sympathetic discharge. Second order electrical control of the myocardium is closely tied to parasympathetic influence from the spinal vertebral ganglia and vagus nerves.

Pathology

Occlusion of the coronary arteries by atherosclerosis and/or thrombosis can lead to myocardial infarction.

Certain viruses lead to inflammation of the myocardium, or myocarditis.

Cardiomyopathies are inherent diseases of the myocardium, many of which are caused by genetic mutations.

Failure of the heart to contract properly (for various reasons) is often termed heart failure although the proper term for this condition is myocardial failure. Heart failure is a general term referring to overwhelming heart disease from many causes (e.g., myocardial failure, valvular heart disease, increased ventricular stiffness) resulting in the inability of the heart to maintain normal ventricular filling pressure (resulting in fluid retention, edema, pulmonary oedema, hepatomegaly) and/or reduced blood flow to the body either at rest or during exercise. Myocardial failure resulting in heart failure results in a shortened life expectancy and decreased quality of life.

Disease of myocardium

Noncompaction Cardiomyopathy, is when the Myocardium tissue fails to compact as the human embryo develops.

Disease of the myocardium can also be considered to be ischemic (poor blood supply to the heart muscle) or nonischemic, implying disease within the heart muscle itself.

1. Ischemic myocardial disease is well described and is amenable to vessel bypass, stents, applied growth factors and many other interventions.

a. Diabetes is perhaps the best known physiologic model for accelerated ischemic disease of the myocardium.

2. Nonischemic myocardial disease (see also nonischemic cardiomyopathy) is an entirely different entity in myocardial disease.

a. Chagasic heart failure (see also Carlos Chagas) is perhaps the best known physiologic model in myocardial autonomic insufficiency.

External links

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Anatomy of torso, cardiovascular system: heart
Structuresatria (interatrial septum, musculi pectinati) • ventricles (interventricular septum, trabeculae carneae, chordae tendinae, papillary muscle) • valves • cusps
Regionsbase • apex • grooves (coronary/atrioventricular, interatrial, anterior interventricula, posterior interventricular) • surfaces (sternocostal, diaphragmatic) • borders (right, left)
Right heart(vena cavae, coronary sinus) → right atrium (auricle, fossa ovalis, limbus of fossa ovalis, crista terminalis, valve of the inferior vena cava, valve of the coronary sinus) → tricuspid valve → right ventricle (conus arteriosus, moderator band/septomarginal trabecula)  → pulmonary valve → (pulmonary artery and pulmonary circulation)
Left heart(pulmonary veins) → left atrium (auricle) → mitral valve → left ventricle → aortic valve (aortic sinus) → (aorta and systemic circulation)
Layerspericardium  (sinus) • epicardium • myocardium • endocardium • cardiac skeleton (fibrous trigone, fibrous rings)
Conduction systemCardiac pacemaker • SA node • AV node• bundle of His • Purkinje fibers
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Histology: muscle tissue
skeletal muscle/generalepimysium, 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) costamere (dystrophin, α,β-dystrobrevin, syncoilin, synemin/desmuslin, dysbindin, sarcoglycan, dystroglycan, sarcospan), desmin neuromuscular junction, motor unit, muscle spindle, excitation-contraction coupling, sliding filament mechanism myoblast, satellite cell, sarcoplasm, sarcolemma, sarcoplasmic reticulum, T-tubule
cardiac musclemyocardium, intercalated disc, nebulette
smooth musclecalmodulin, vascular smooth muscle
Arteries are muscular blood vessels that carry blood away from the heart.[1] All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.

The circulatory system is extremely important for sustaining life.
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The coronary circulation is the circulation of blood in the blood vessels that supply blood to and from the heart muscle itself. Although blood fills the chambers of the heart, the muscle tissue of the heart, or myocardium, is so thick that it requires coronary blood vessels to
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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MUSCLE (multiple sequence comparison by log-expectation) is public domain, multiple sequence alignment software for protein and nucleotide sequences.
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heart is a muscular organ responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in the annelids, mollusks, and arthropods.
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In the heart, the endocardium is the innermost layer of tissue that lines the chambers of the heart. Its cells, embryologically and biologically, are similar to the endothelial cells that line blood vessels.
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endothelium is the thin layer of cells that line the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. Endothelial cells line the entire circulatory system, from the heart to the smallest capillary.
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Epicardium describes the outer layer of heart tissue (from Greek; epi- outer, cardium heart). When considered as a part of the pericardium, it is the inner layer, or visceral pericardium.
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Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, muscle, and nervous tissue.) It is largely a category of exclusion rather than one with a precise definition, but all or most tissues in this category are similarly:
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The pericardium is a double-walled sac that contains the heart and the roots of the great vessels.

Layers

There are two layers to this sac: the fibrous pericardium and the serous pericardium.
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'Cardiac muscle' is a type of involuntary striated muscle found within the heart. Its function is to "pump" blood through the circulatory system by contracting.
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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. While under tension, the muscle may lengthen, shorten or remain the same.
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An action potential is a "spike" of electrical discharge that travels along the membrane of a cell. Action potentials are an essential feature of animal life, rapidly carrying information within and between tissues. They also occur in some plants.
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Conduction is the movement of electrically charged particles through a transmission medium (electrical conductor). The movement can form an electric current in response to an electric field. The underlying mechanism for this movement depends on the material.
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Neurons (also known as neurones and nerve cells) are electrically excitable cells in the nervous system that process and transmit information. In vertebrate animals, neurons are the core components of the brain, spinal cord and peripheral nerves.
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A nerve is an enclosed, cable-like bundle of axons (the long, slender projection of a neuron). Neurons are sometimes called nerve cells, though this term is technically imprecise since many neurons do not form nerves, and nerves also include the glial cells that
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The coronary circulation is the circulation of blood in the blood vessels that supply blood to and from the heart muscle itself. Although blood fills the chambers of the heart, the muscle tissue of the heart, or myocardium, is so thick that it requires coronary blood vessels to
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Atherosclerosis
Classification & external resources

Changes in endothelial dysfunction in atherosclerosis (note text comments about geometry error)
ICD-10 I 70.
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MeSH D013927 Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. Thromboembolism is a general term describing both thrombosis and its main complication which is embolisation.
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Myocardial infarction
Classification & external resources

Diagram of a myocardial infarction (2) of the tip of the anterior wall of the heart (an apical infarct
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Inflammation (Latin, inflammatio, to set on fire) is the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants.
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MeSH D009205 In medicine (cardiology), myocarditis is inflammation of the myocardium, the muscular part of the heart. It is generally due to infection (viral or bacterial). It may present with chest pain, rapid signs of heart failure, or sudden death.
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MeSH D009202 Cardiomyopathy, which literally means "heart muscle disease", is the deterioration of the function of the myocardium (i.e., the actual heart muscle) for any reason. People with cardiomyopathy are often at risk of arrhythmia or sudden cardiac death or both.
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Heart failure
Classification & external resources

ICD-10 I 50.0
ICD-9 428.0

DiseasesDB 16209
MedlinePlus 000158
eMedicine med/3552  
MeSH D006333

Congestive heart failure (CHF), also called
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Heart failure
Classification & external resources

ICD-10 I 50.0
ICD-9 428.0

DiseasesDB 16209
MedlinePlus 000158
eMedicine med/3552  
MeSH D006333

Congestive heart failure (CHF), also called
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Water retention can refer to:
  • Edema or peripheral edema
  • Premenstrual water retention
  • A water retention curve for soil water potential

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Edema
Classifications and external resources

ICD-10 R 60.9
ICD-9 782.3

DiseasesDB 9148

This page is about the medical condition. For the rock band, see Adema.

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Pulmonary edema
Classification & external resources

ICD-10 J 81.
ICD-9 514

DiseasesDB 11017
MedlinePlus 000140
eMedicine med/1955   radio/581 Pulmonary edema
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<noinclude> </noinclude> Hepatotoxicity (from hepatic toxicity) implies chemical-driven liver damage. Liver plays central role in transformation and clearance of most chemicals and is susceptible to the toxicity from these agents.
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Homo.
Upper Paleolithic 33 At age 15: 39 (to age 54)[3][4]
Neolithic 20  
Bronze Age 18[5]  
Classical Greece 25-45  
Classical Rome 25-45  
Medieval Britain 20-30  
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