同: SA

同: SA

WordNet

Nazi militia created by Hitler in 1921 that helped him to power but was eclipsed by the SS after 1943 (同)Sturmabteilung, Storm Troops
used to express refusal or denial or disagreement etc or especially to emphasize a negative statement; "no, you are wrong"
a negative; "his no was loud and clear"
referring to the degree to which a certain quality is present; "he was no heavier than a child" (同)no more
not in any degree or manner; not at all; "he is no better today"
quantifier; used with either mass nouns or plural count nouns for indicating a complete or almost complete lack or zero quantity of; "we have no bananas"; "no eggs left and no money to buy any"; "have you no decency?"; "did it with no help"; "Ill get you there in no time"
sway gently back and forth, as in a nodding motion; "the flowers were nodding in the breeze"
be almost asleep; "The old man sat nodding by the fireplace"
let the head fall forward through drowsiness; "The old man was nodding in his chair"
the act of nodding the head
a sign of assent or salutation or command
express or signify by nodding; "He nodded his approval"
lower and raise the head, as to indicate assent or agreement or confirmation; "The teacher nodded when the student gave the right answer"
any thickened enlargement (同)knob, thickening
(botany) the small swelling that is the part of a plant stem from which one or more leaves emerge (同)leaf node
a connecting point at which several lines come together
(computer science) any computer that is hooked up to a computer network (同)client, guest
(astronomy) a point where an orbit crosses a plane
(physics) the point of minimum displacement in a periodic system
any bulge or swelling of an anatomical structure or part

PrepTutorEJDIC

《名詞の前に置いて》『一つも』(『一人も,少しも』)・・・『ない』 / 《補語につけて》『決して・・・でない』 / 《省略文で》・・・なし;・・・お断り / 《話》少ししか(あまり)・・・ない / (肯定の問いに対して)『いいえ』;(否定の問いに対して)はい,ええ / 《not, norの前に挿入して》『いや』,否 / 《形容詞の前に置その形容詞を否定して》…どころではない / 《比較級の前に置いて》ちっとも…でない,…と全く同じ / 《… or no の形で》…であってもなくても / 《驚き・困惑・不信などを表して》とんでもない / 《単数形で》『拒否』,「『いいえ』」という返事 / 《複数形で》反対[投]票
(承諾・あいさつ・合図などで)『うなずく』,会釈する / (眠くて)『こっくりする』,(油断して)うとうとする《+off》 / 〈草木・穂などが〉揺れる / (承諾・あいさつなどで)〈頭〉‘を'『うなずかせる』 / …‘を'うなずいて示す / 《副詞[句]を伴って》〈人〉‘に'うなずいて示す / 《同意・承諾・あいさつ・命令など,また時には拒絶を表して》(…に対する)『うなずき』,『会釈』《+『to』+『名』》;(眠気による)こっくり
(茎・幹の)節(ふし) / (体組織にできた)結節,こぶ(リンパ瘤(りゅう)など) / (天体の軌道の)交点 / (物事の)中心点

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/01/14 22:30:44」(JST)

wiki en

[Wiki en表示]

The sinoatrial node (also commonly spelled sinuatrial node, abbreviated SA node or SAN, also called the sinus node) is the impulse-generating (pacemaker) tissue located in the right atrium of the heart, and thus the generator of normal sinus rhythm. It is a group of cells positioned on the wall of the right atrium, near the entrance of the superior vena cava. These cells are specialized cardiomyocytes. Though they possess some contractile filaments, they do not contract robustly.

The SAN was first described in 1907 by Arthur Keith and Martin Flack.^[1]

Role as a pacemaker[edit]

Although all of the heart's cells have the ability to generate the electrical impulses (or action potentials) that trigger cardiac contraction, the sinoatrial node normally initiates it, simply because it generates impulses slightly faster than the other areas with pacemaker potential. Cardiomyocytes, like all muscle cells, have refractory periods following contraction during which additional contractions cannot be triggered; their pacemaker potential is overridden by the sinoatrial or atrioventricular nodes.

In the absence of extrinsic neural and hormonal control, cells in the sinoatrial node (SA node), situated in the upper right corner of the heart, will naturally discharge (create action potentials) upwards of 100 beats/minute.^[2] Because the sinoatrial node is responsible for the rest of the heart's electrical activity, it is sometimes called the primary pacemaker.

If the SA node does not function, or the impulse generated in the SA node is blocked before it travels down the electrical conduction system, a group of cells further down the heart will become the heart's pacemaker.^[3] These cells form the atrioventricular node (AV node), which is an area between the atria and ventricles, within the atrial septum. If the AV node also fails, Purkinje fibers (or known by some as the bundle of His) are capable of acting as the pacemaker. The reason Purkinje cells do not normally control the heart rate is that they generate action potentials at a lower frequency than the AV or SA nodes.

Histology[edit]

High magnification micrograph of sinoatrial node tissue and an adjacent nerve fibre. H&E stain.

The sinoatrial node is submyocardial at the lateral aspect of the junction of the superior vena cava and right atrium. Its deep aspect abuts cardiac myocytes belonging to the right atrium. Its superficial aspect is covered by adipose tissue. The SA node fibres vaguely resemble cardiac myocytes; however, they are measurably thinner, more tortuous and stain less intensely (on H&E) than cardiac myocytes.

Innervation[edit]

The SA node is richly innervated by parasympathetic nervous system fibers (CN X: Vagus Nerve) and by sympathetic nervous system fibers (T1-4, Spinal Nerves). This unique anatomical arrangement makes the SA node susceptible to distinctly paired and opposed autonomic influences.

Stimulation of the vagus nerves (the parasympathetic fibers) causes a decrease in the SA node rate (thereby decreasing the heart rate). Parasympathetic fibers cannot change the force of contraction, however,because they only innervate the SA node and AV node (which control heart rate only)***(NOTE: This statement is not entirely accurate. The following study: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2278718/ demonstrates how the parasympathetic nervous system, through the action of vagus nerve, exerts a negative inotropic effect upon the heart)
Stimulation via sympathetic fibers causes an increase in the SA node rate (thereby increasing the heart rate and force of contraction). Sympathetic fibers can increase the force of contraction because in addition to innervating the SA and AV nodes, they innervate the atria and ventricles themselves.

Blood supply[edit]

The SA node receives blood supply from the SA node artery (ramus nodi sinuatrialis). Anatomical dissection studies have shown that this supply may be branch of the right coronary artery in the majority (about 60-70%) of hearts, and a branch of the left coronary artery (usually the left circumflex artery) in about 20-30% of hearts.^[4] Rarer variants may include blood supply from both right and left coronary arteries or two branches of the right coronary artery.^[5] Occlusion of the arterial blood supply to the SA node (most commonly due to a myocardial infarction) can therefore cause ischaemia and cell death in the SA node. This can disrupt the electrical pacemaker function of the SA node, and can result in sick sinus syndrome.

Sinus node dysfunction[edit]

Sinus node dysfunction describes an irregular heartbeat caused by faulty electrical signals of the heart. When the heart's sinoatrial node is defective, the heart’s rhythms become abnormal – either too fast, too slow, or a combination.^[6]

Additional images[edit]

Heart; conduction system
Schematic representation of the atrioventricular bundle

References[edit]

^ Boyett MR, Dobrzynski H (June 2007). "The sinoatrial node is still setting the pace 100 years after its discovery". Circ. Res. 100 (11): 1543–5. doi:10.1161/CIRCRESAHA.107.101101. PMID 17556667. Cite uses deprecated parameters (help)
^ AnatomySAnode
^ http://emedicine.medscape.com/article/155146-overview
^ Pejković, B.; Krajnc, I.; Anderhuber, F.; Kosutić, D. (2008). "Anatomical aspects of the arterial blood supply to the sinoatrial and atrioventricular nodes of the human heart". The Journal of international medical research 36 (4): 691–698. PMID 18652764. edit
^ Onciu, M.; Tuţă, L. A.; Baz, R.; Leonte, T. (2006). "Specifics of the blood supply of the sinoatrial node". Revista medico-chirurgicala a Societatii de Medici si Naturalisti din Iasi 110 (3): 667–673. PMID 17571564. edit
^ Sinus node dysfunction Mount Sinai Hospital, New York

External links[edit]

sinuatrial+node at eMedicine Dictionary
SUNY Figs 20:06-01 - "The conduction system of the heart."
Diagram at gru.net
thoraxlesson4 at The Anatomy Lesson by Wesley Norman (Georgetown University) (thoraxheartinternalner)
http://www.healthyheart.nhs.uk/heart_works/heart03.shtml

UpToDate Contents

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1. 洞房結節の解剖学および電気生理学 anatomy and electrophysiology of the sinoatrial node
2. 心電図チュートリアル：洞結節での調律および不整脈 ecg tutorial rhythms and arrhythmias of the sinus node
3. 洞不全症候群の症状および原因 manifestations and causes of the sick sinus syndrome
4. 洞房結節の一時停止、停止、および進出ブロック sinoatrial nodal pause arrest and exit block
5. 洞不全症候群の診断および評価 diagnosis and evaluation of the sick sinus syndrome

English Journal

Characterization of a right atrial subsidiary pacemaker and acceleration of the pacing rate by HCN over-expression.

Morris GM, D'Souza A, Dobrzynski H, Lei M, Choudhury M, Billeter R, Kryukova Y, Robinson RB, Kingston PA, Boyett MR.SourceInstitute of Cardiovascular Sciences, University of Manchester, Core Technology Facility, 46 Grafton Street, Manchester M13 9NT, UK.
Cardiovascular research.Cardiovasc Res.2013 Oct 1;100(1):160-9. doi: 10.1093/cvr/cvt164. Epub 2013 Jun 19.
AIMS: Although the right atrium (RA contains subsidiary atrial pacemaker (SAP) tissue that can take over from the sinoatrial node (SAN) in sick sinus syndrome (SSS), SAP tissue is bradycardic. Little is known about SAP tissue and one aim of the study was to characterize ion channel expression to obt
PMID 23787003

Short-term desensitization of muscarinic k(+) current in the heart.

Murakami S, Inanobe A, Kurachi Y.SourceDivision of Molecular and Cellular Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan; The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan. Electronic address: murakami@pharma2.med.osaka-u.ac.jp.
Biophysical journal.Biophys J.2013 Sep 17;105(6):1515-25. doi: 10.1016/j.bpj.2013.08.009.
Acetylcholine (ACh) rapidly increases cardiac K(+) currents (IKACh) by activating muscarinic K(+) (KACh) channels followed by a gradual amplitude decrease within seconds. This phenomenon is called short-term desensitization and its precise mechanism and physiological role are still unclear. We const
PMID 24048003

Congenital Heart Block Maternal Sera Autoantibodies Target an Extracellular Epitope on the α1G T-Type Calcium Channel in Human Fetal Hearts.

Strandberg LS, Cui X, Rath A, Liu J, Silverman ED, Liu X, Siragam V, Ackerley C, Su BB, Yan JY, Capecchi M, Biavati L, Accorroni A, Yuen W, Quattrone F, Lung K, Jaeggi ET, Backx PH, Deber CM, Hamilton RM.SourceDepartment of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.
PloS one.PLoS One.2013 Sep 9;8(9):e72668. doi: 10.1371/journal.pone.0072668.
BACKGROUND: Congenital heart block (CHB) is a transplacentally acquired autoimmune disease associated with anti-Ro/SSA and anti-La/SSB maternal autoantibodies and is characterized primarily by atrioventricular (AV) block of the fetal heart. This study aims to investigate whether the T-type calcium c
PMID 24039792

Japanese Journal

Modern Perspectives on Numerical Modeling of Cardiac Pacemaker Cell

Maltsev Victor A.,Yaniv Yael,Maltsev Anna V. [他]
Journal of pharmacological sciences 125(1), 6-38, 2014-05
NAID 40020066413

Contribution of Ca2+ crosstalk between mitochondria and sarcoplasmic reticulum to the cardiac pacemaker activity

,
生体医工学 52(Supplement), OS-80-OS-81, 2014
… crosstalk to the automaticity of pacemaker sinoatrial (SA) node cells. … dynamics and a subspace between mitochondria and SR into a SA node cell model by Maltsev and Lakatta (2009), in which spontaneous SR Ca<SUP>2+</SUP> … crosstalk plays important roles in automaticity of SA node cells. …
NAID 130004948298

Fibrosis, Electrics and Genetics:– Perspectives on Sinoatrial Node Disease –

,
Circulation Journal 78(6), 1272-1282, 2014
… The sinoatrial node (SAN) is the normal pacemaker of the heart. …
NAID 130004427928

Related Pictures

★リンクテーブル★

リンク元	「SA node」「sino-atrial node」
関連記事	「node」「sinoatrial」「nod」

「SA node」

Sinoatrial node
	Low magnification micrograph of a sinoatrial node (center-right on image) and its surrounding tissue. The SA node surrounds the (sinuatrial) nodal artery (on lumen in the image), a branch of the right coronary artery, abuts cardiac myocytes (of the right atrium) on its deep aspect (left of image) and adipose tissue on its superficial (epicardial) aspect (right of image). H&E stain.
	Isolated Heart conduction system, showing SA node
Latin	nodus sinuatrialis
Artery	sinuatrial nodal artery
MeSH	Sinoatrial+Node

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洞房結節

関: sino-atrial node、sinoatrial node、sinus node

「sino-atrial node」

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