WordNet

small room in which a monk or nun lives (同)cubicle
a device that delivers an electric current as the result of a chemical reaction (同)electric cell
a room where a prisoner is kept (同)jail cell, prison cell
(biology) the basic structural and functional unit of all organisms; they may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals
any small compartment; "the cells of a honeycomb"
a small unit serving as part of or as the nucleus of a larger political movement (同)cadre
make ones way by force; "He muscled his way into the office"
animal tissue consisting predominantly of contractile cells (同)muscular_tissue
one of the contractile organs of the body (同)musculus
authority or power or force (especially when used in a coercive way); "the senators used their muscle to get the party leader to resign"
of or relating to the heart; "cardiac arrest"
the opening into the stomach and that part of the stomach connected to the esophagus

PrepTutorEJDIC

(刑務所の)『独房』;(修道院の)小さい独居室 / (ミツバチの)みつ房,巣穴 / 小さい部屋 / 『細胞』 / 電池 / 花粉室 / (共産党などの)細胞
〈U〉(動物体の組織としての)『筋肉』,筋(きん);〈C〉(体の各部を動かす)筋肉 / 〈U〉力,(特に)筋力,腕力 / 《俗に》(…に)強引に割り込む《+『in on』(『into, through』)+『名』》
心臓の
筋肉の,筋力のある / 力ずくの

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/08/15 04:47:14」(JST)

wiki en

Cardiac muscle cells or cardiomyocytes (also known as myocardiocytes^[1] or cardiac myocytes^[2]) are the muscle cells (myocytes) that make up the cardiac muscle. Each myocardial cell contains myofibrils, which are specialized organelles consisting of long chains of sarcomeres, the fundamental contractile units of muscle cells. Cardiomyocytes show striations similar to those on skeletal muscle cells, but unlike multinucleated skeletal cells, they contain only one nucleus. Cardiomyocytes have a high mitochondrial density, which allows them to produce adenosine triphosphate (ATP) quickly, making them highly resistant to fatigue.

The two types of cells

There are two types of cells within the heart: the cardiomyocytes and the cardiac pacemaker cells. Cardiomyocytes make up the atria (the chamber in which blood enters the heart) and ventricles (where blood is pumped out of the heart) of the heart. These cells must be able to shorten and lengthen their fibers and the fibers must be flexible enough to stretch. These functions are critical to the proper form during the beating of the heart.^[3]

Cardiac pacemaker cells carry the impulses that are responsible for the beating of the heart. They are distributed throughout the heart and are responsible for several functions. First, they are responsible for being able to spontaneously generate and send out electrical impulses. They also must be able to receive and respond to electrical impulses from the brain. Lastly, they must be able to transfer electrical impulses from cell to cell.^[4]

All of these cells are connected by cellular bridges. Porous junctions called intercalated discs form junctions between the cells. They permit sodium, potassium and calcium to easily diffuse from cell to cell. This makes it easier for depolarization and repolarization in the myocardium. Because of these junctions and bridges the heart muscle is able to act as a single coordinated unit.^[5]^[6]

Depolarization/repolarization cycle

Cardiac action potential consists of two cycles, a rest phase and an active phase. These two phases are commonly understood as systole and diastole. The rest phase is considered polarized. The resting potential during this phase of the beat separates the ions such as sodium, potassium and calcium. Myocardial cells possess the property of automaticity or spontaneous depolarization. This is the direct result of a membrane which allows sodium ions to slowly enter the cell until the threshold is reached for depolarization. Calcium ions follow and extend the depolarization even further. Once calcium stops moving inward, potassium ions move out slowly to produce repolarization. The very slow repolarization of the CMC membrane is responsible for the long refractory period.^[7]^[8]

Myocardial infarction

Myocardial infarction, commonly known as a heart attack, occurs when the heart's supplementary blood vessels are obstructed by an unstable build-up of white blood cells, cholesterol, and fat. With no blood flow, the cells die causing whole portions of cardiac tissue to die. Once these tissues are lost, they cannot be replaced, thus causing permanent damage. Current research indicates, however, that it may be possible to repair damaged cardiac tissue with stem cells.^[9]

Growth and renewal

Humans are born with a set number of heart muscle cells, or cardiomyocytes, which increase in size as our heart grows larger during childhood development. Recent evidence suggests that cardiomyocytes are actually slowly turned over as we age, but that less than 50% of the cardiomyocytes we are born with are replaced during a normal life span.^[10] The growth of individual cardiomyocytes not only occurs during normal heart development, it also occurs in response to extensive exercise (athletic heart syndrome), heart disease, or heart muscle injury such as after a myocardial infarction. A healthy adult cardiomyocyte has a cylindrical shape that is approximately 100μm long and 10-25μm in diameter. Cardiomyocyte hypertrophy occurs through sarcomerogenesis, the creation of new sarcomere units in the cell. During heart volume overload, cardiomyocytes grow through eccentric hypertrophy.^[11] The cardiomyocytes extend lengthwise but have the same diameter, resulting in ventricular dilation. During heart pressure overload, cardiomyocytes grow through concentric hypertrophy.^[11] The cardiomyocytes grow larger in diameter but have the same length, resulting in heart wall thickening.

References

^ Wolfgang Kühnel (1 January 2003). Color atlas of cytology, histology, and microscopic anatomy. Thieme. pp. 172–. ISBN 978-3-13-562404-4. Retrieved 18 April 2010.
^ Julian Seifter; Austin Ratner; David Sloane (1 October 2005). Concepts in medical physiology. Lippincott Williams & Wilkins. pp. 201–. ISBN 978-0-7817-4489-8. Retrieved 18 April 2010.
^ Severs, Nicholas. "The Cardiac Muscle Cell" (PDF). Retrieved 2012.
^ "Anatomy and Physiology of the Heart". Retrieved 2012.
^ "American Heart Association: How the Heart Works". Retrieved 2012.
^ Martini, Frederic. "The Fundamentals of Anatomy and Physiology: Chapter 10 Cardiac Muscle Tissue".
^ Klabunde, Richard. "Cardiovascular Physiology= Cardiac muscle Concept". Retrieved 2012.
^ "Cells Alive: Pumping Myocytes". Retrieved 2012.
^ "Stem Cell Research News". Retrieved 2012.
^ Bergmann, O.; Bhardwaj, R. D.; Bernard, S.; Zdunek, S.; Barnabe-Heider, F.; Walsh, S.; Zupicich, J.; Alkass, K.; Buchholz, B. A.; Druid, H.; Jovinge, S.; Frisen, J. (3 April 2009). "Evidence for cardiomyocyte renewal in humans". Science 324 (5923): 98–102. doi:10.1126/science.1164680. PMC 2991140. PMID 19342590.
^ ^a ^b Göktepe, S; Abilez, OJ; Parker, KK; Kuhl, E (2010-08-07). "A multiscale model for eccentric and concentric cardiac growth through sarcomerogenesis". Journal of Theoretical Biology 265 (3): 433–42. doi:10.1016/j.jtbi.2010.04.023. PMID 20447409.

UpToDate Contents

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1. 心臓腫瘍 cardiac tumors
2. 筋力低下患者へのアプローチ approach to the patient with muscle weakness
3. 鈍的外傷による心損傷 cardiac injury from blunt trauma
4. 自家造血幹細胞移植の適格性判定 determining eligibility for autologous hematopoietic cell transplantation
5. 心筋障害のバイオマーカーとしてのトロポニンおよびクレアチンキナーゼ troponins and creatine kinase as biomarkers of cardiac injury

English Journal

Selective Life-Long Skeletal Myofiber-Targeted VEGF Gene Ablation Impairs Exercise Capacity in Adult Mice.

Tang K1, Gu Y1, Dalton ND1, Wagner H1, Peterson KL1, Wagner PD1, Breen EC1.
Journal of cellular physiology.J Cell Physiol.2016 Feb;231(2):505-11. doi: 10.1002/jcp.25097.
Exercise is dependent on adequate oxygen supply for mitochondrial respiration in both cardiac and locomotor muscle. To determine whether skeletal myofiber VEGF is critical for regulating exercise capacity, independent of VEGF function in the heart, ablation of the VEGF gene was targeted to skeletal
PMID 26201683

Potential Role of Glycogen Synthase Kinase-3β in Regulation of Myocardin Activity in Human Vascular Smooth Muscle Cells.

Zhou YX1, Shi Z1, Singh P1, Yin H1, Yu YN2, Li L2, Walsh MP1, Gui Y3, Zheng XL1.
Journal of cellular physiology.J Cell Physiol.2016 Feb;231(2):393-402. doi: 10.1002/jcp.25084.
Glycogen synthase kinase (GSK)-3β, a serine/threonine kinase with an inhibitory role in glycogen synthesis in hepatocytes and skeletal muscle, is also expressed in cardiac and smooth muscles. Inhibition of GSK-3β results in cardiac hypertrophy through reducing phosphorylation and increasing transc
PMID 26129946

Heart-on-a-chip based on stem cell biology.

Jastrzebska E1, Tomecka E2, Jesion I3.
Biosensors & bioelectronics.Biosens Bioelectron.2016 Jan 15;75:67-81. doi: 10.1016/j.bios.2015.08.012. Epub 2015 Aug 13.
Heart diseases are one of the main causes of death around the world. The great challenge for scientists is to develop new therapeutic methods for these types of ailments. Stem cells (SCs) therapy could be one of a promising technique used for renewal of cardiac cells and treatment of heart diseases.
PMID 26298640

Japanese Journal

心電図の数理

岡田純一
応用数理 22(4), 238-246, 2012-12-21
… In this article, we introduce mathematical models of ion current dynamics in the cardiac cell and their relation with ECG through the bidomain equation on the torso model constructed based on realistic morphology. … By doing such a simulation, it becomes possible to analyze the correlation between the ion currents on the heart muscle and the body surface potential map. …
NAID 110009579037

肥大型心筋症の病理 (特集心疾患の病理)

森本紳一郎,加藤靖周,大槻眞嗣
循環器内科 72(6), 549-556, 2012-12-00
NAID 40019549168

Analysis of TdT-Mediated dUTP Nick End Labeling (TUNEL)-Positive Cells Associated with Cardiac Myogenesis in Mouse Embryo

NAGANUMA Yuki,ICHII Osamu,OTSUKA Saori,HASHIMOTO Yoshiharu,KON Yasuhiro
Journal of Veterinary Medical Science, 2012
… Caspase activation is associated with skeletal muscle differentiation in mice embryos. … We examined the relationship between cardiac myogenesis and cell death using mice hearts at embryonic days (E) 11.5–15.5 and fetal rat heart H9C2 cells. … From these findings, we concluded that the increased number of TUNEL-positive cardiomyocyte, having the DNA strand breaks, would be associated with the progression of cardiac myogenesis. …
NAID 130001879616

Related Pictures

★リンクテーブル★

リンク元	「cardiomyocyte」「cardiac myocyte」「myocardial cell」「heart muscle cell」
関連記事	「cardiac」「muscle cell」「cell」「muscle」

「cardiomyocyte」

Cardiac muscle cell
	Illustration of a myocardiocyte, including organelles and cell membrane functions
Details
Latin	cardiomyocytus; myocytus cardiacus
Identifiers
Code	TH H2.00.05.2.02004
	Anatomical terminology