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

WordNet

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
Nazi militia created by Hitler in 1921 that helped him to power but was eclipsed by the SS after 1943 (同)Sturmabteilung, Storm Troops
the 19th letter of the Roman alphabet (同)s

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
sulfurの化学記号 / {略}South[ern]

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/02/03 08:42:27」(JST)

wiki en

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.

Structure

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

Location

The sinoatrial node is a group of cells positioned in the wall of the right atrium just lateral to the junction where the superior vena cava enters the right atrium. The SA node is located in the tissue beneath the myocardium. Its deep aspect abuts cardiac myocytes belonging to the right atrium, while its superficial aspect is covered by adipose tissue. It extends between 1 and 2 cm on the right from the crest of the right auricle and runs posteroinferiorly into the upper part of the terminal groove. SA node fibres are specialized cardiomyocytes that vaguely resemble cardiac myocytes; however, although they possess some contractile filaments they do not contract as robustly. Additionally, SA node fibers are measurably thinner, more tortuous and stain less intensely (with an H&E stain) than cardiac myocytes.

Innervation

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

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.^[1] Rarer variants may include blood supply from both right and left coronary arteries or two branches of the right coronary artery.^[2]

Function

Pacemaking

Although some 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.^[3] Because the sinoatrial node is responsible for the rest of the heart's electrical activity, it is sometimes called the primary pacemaker.

Clinical significance

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.^[4]

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.

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.^[5] 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.

History

The SAN was first described in 1907 by Arthur Keith and Martin Flack.^[6]

Additional images

Heart; conduction system
Schematic representation of the atrioventricular bundle

References

^ 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. doi:10.1177/147323000803600410. 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
^ AnatomySAnode
^ Sinus node dysfunction Mount Sinai Hospital, New York
^ http://emedicine.medscape.com/article/155146-overview^{[full citation needed]}
^ 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.

External links

sinuatrial+node at eMedicine Dictionary
Anatomy figure: 20:06-01 at Human Anatomy Online, SUNY Downstate Medical Center - "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. 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
3. 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
4. 洞徐脈 sinus bradycardia
5. 洞不全症候群の症状および原因 manifestations and causes of the sick sinus syndrome

English Journal

The cardiac sodium-calcium exchanger NCX1 is a key player in the initiation and maintenance of a stable heart rhythm.

Herrmann S, Lipp P, Wiesen K, Stieber J, Nguyen H, Kaiser E, Ludwig A.SourceInstitut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen D-91054, Germany.
Cardiovascular research.Cardiovasc Res.2013 Sep 1;99(4):780-8. doi: 10.1093/cvr/cvt154. Epub 2013 Jun 12.
AIMS: The complex molecular mechanisms underlying spontaneous cardiac pacemaking are not fully understood. Recent findings point to a co-ordinated interplay between intracellular Ca(2+) cycling and plasma membrane-localized cation transport determining the origin and periodicity of pacemaker potenti
PMID 23761399

Apamin modulates electrophysiological characteristics of the pulmonary vein and the Sinoatrial Node.

Chen WT, Chen YC, Lu YY, Kao YH, Huang JH, Lin YK, Chen SA, Chen YJ.SourceDivision of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
European journal of clinical investigation.Eur J Clin Invest.2013 Sep;43(9):957-63. doi: 10.1111/eci.12125. Epub 2013 Jul 9.
BACKGROUND: Small-conductance calcium-activated potassium (SK) channels play an important role in atrial electrophysiology. Blocking SK channels prolongs action potential (AP) duration and attenuate electrical remodelling. The effects of SK blocking on the pulmonary vein (PV) and the sinoatrial node
PMID 23834267

Sudden cardiac death due to arrhythmogenic right ventricular cardiomyopathy and cystic tumor of the AV node.

Cavanaugh J, Prahlow JA.SourceIndiana University School of Medicine-South Bend, South Bend, IN, USA.
Forensic science, medicine, and pathology.Forensic Sci Med Pathol.2013 Sep;9(3):407-12. doi: 10.1007/s12024-013-9434-6. Epub 2013 Apr 6.
An 18-year-old white male collapsed suddenly in his home and died. At autopsy, the right ventricle of the decedent was noted to be dilated with marked thinning of the wall focally. Microscopically, the myocardium of the right ventricle was noted to be significantly thinned focally, where transmural
PMID 23564062

Japanese Journal

A Bootstrapped Analog Switch with Constant On-Resistance

KIM Sang-hun,LEE Yong-Hwan,CHUNG Hoon-Ju,JANG Young-Chan
IEICE transactions on electronics 94(6), 1069-1071, 2011-06-01
… A bootstrapped analog switch with constant on-resistance is proposed for the successive approximation (SA) analog-to-digital converters (ADCs) that have many input-sampling switches. … To evaluate the proposed bootstrapped analog switch, the 10-bit 1MS/s CMOS SA ADC with a rail-to-rail differential input signal was designed by using a 0.18µm CMOS process with 1.0V supply voltage. …
NAID 10029804360

Switch Port Allocation in WDM Networks with Hybrid Optical-Electronic Switching Nodes

VESARACH Pratkasem,SAENGUDOMLERT Poompat
IEICE transactions on communications 94(4), 928-939, 2011-04-01
… We investigate the problem of switch port allocation in WDM networks that use the hybrid optical-electronic switching node architecture. … However, due to the high computational complexity of exact optimization, we develop a simulated annealing (SA) algorithm to get an approximate solution. …
NAID 10029503931

Related Pictures

★リンクテーブル★

リンク元	「洞房結節」「sino-atrial node」
関連記事	「node」「SA」「S」「nod」

「洞房結節」

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
Details
Latin	nodus sinuatrialis
Artery	Sinuatrial nodal artery
Identifiers
MeSH	A07.541.409.819
Dorlands; /Elsevier	12577255
TA	A12.1.06.003
FMA	9477
	Anatomical terminology

　　[★]

英: sinuatrial node (N,Z), SA node sino-atrial node
同: キース・フラック結節,SA結節、洞結節 sinus node

生理

ペースメーカーと呼ばれている

自動的興奮性を有する
房室結節細胞やプルキンエ線維も自動的興奮性を有するが、閾電位に達する前に興奮が伝導してくるので、これらの自動性は潜在的

洞房結節の活動電位の発生にはNaチャネルの活性化はほとんど関与しない(授業プリント)

解剖

心臓の前外部で上大静脈と右心房の境界部で、心外膜のすぐ下に位置する(M.94)
右心房の内面で、上大静脈の開口のすぐ右側にあって、網状の特殊心筋線維からできる小部(KL.294)
長さ約25mm、幅2mm (KL.294)
洞房結節から特殊心筋線維が心房内に放散し、その筋層に移行している (KL.294)

「sino-atrial node」

　　[★]

洞房結節

関: SA node、sinoatrial node、sinus node

「node」

　　[★]

n.

結節、リンパ節、節、ノード

関: clause、ganglia、ganglion、ganglionic、knot、lymph node、nodal、nodose、nodulate、section、tubercle、tubercular、tuberosity

「SA」

　　[★]

「S」

　　[★]

「nod」

　　[★] 　　　　　　　　

[1] 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. doi:10.1177/147323000803600410. PMID 18652764. edit

[2] 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

[3] AnatomySAnode

[4] Sinus node dysfunction Mount Sinai Hospital, New York

[5] ttp://emedicine.medscape.com/article/155146-overview^{[full citation needed]}

[pmid17556667-6] 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.

匿名

検索

案内

案内

SA node