WordNet

toward or on the right; also used figuratively; "he looked right and left"; "the party has moved right"
(frequently plural) the interest possessed by law or custom in some intangible thing; "mineral rights"; "film rights"
anything in accord with principles of justice; "he feels he is in the right"; "the rightfulness of his claim" (同)rightfulness
a turn toward the side of the body that is on the south when the person is facing east; "take a right at the corner"
the hand that is on the right side of the body; "he writes with his right hand but pitches with his left"; "hit him with quick rights to the body" (同)right_hand
those who support political or social or economic conservatism; those who believe that things are better left unchanged (同)right wing
an abstract idea of that which is due to a person or governmental body by law or tradition or nature; "they are endowed by their Creator with certain unalienable Rights"; "Certain rights can never be granted to the government but must be kept in the hands
location near or direction toward the right side; i.e. the side to the south when a person or object faces east; "he stood on the right"
make reparations or amends for; "right a wrongs done to the victims of the Holocaust" (同)compensate, redress, correct
correct in opinion or judgment; "time proved him right" (同)correct
exactly; "he fell flop on his face" (同)flop
an interjection expressing agreement (同)right on
intended for the right hand; "a right-hand glove" (同)right-hand
(of the side of cloth or clothing) facing or intended to face outward; "the right side of the cloth showed the pattern"; "be sure your shirt is right side out"
being or located on or directed toward the side of the body to the east when facing north; "my right hand"; "right center field"; "a right-hand turn"; "the right bank of a river is the bank on your right side when you are facing downstream"
completely; "she felt right at home"; "he fell right into the trap"
having the axis perpendicular to the base; "a right angle"
immediately; "she called right after dinner"
in conformance with justice or law or morality; "do the right thing and confess"
in or into a satisfactory condition; "things are right again now"; "put things right"
of or belonging to the political or intellectual right
precisely, exactly; "stand right here!"
put in or restore to an upright position; "They righted the sailboat that had capsized"
regain an upright or proper position; "The capsized boat righted again"
connect or secure to; "They rigged the bomb to the ignition"
formation of masts, spars, sails, etc., on a vessel (同)rigging
gear (including necessary machinery) for a particular enterprise
manipulate in a fraudulent manner; "rig prices" (同)manipulate
arrange the outcome of by means of deceit; "rig an election" (同)set_up
equip with sails or masts; "rig a ship" (同)set, set_up
the central area in a building; open to the sky
any chamber that is connected to other chambers or passageways (especially one of the two upper chambers of the heart)

PrepTutorEJDIC

Regular Army正規軍
《名試の前にのみ用いて》『右の』,右側の / 《しばしば『R-』》(政治上)『右派の』,保守的な / 〈U〉《the~》『右』,右側,右方 / 〈C〉『右手』(right hand) / 〈U〉《集合的に》《しばしばthe R-》(政治上の)右派,保守派 / 〈C〉(野球の)右翼(right field) / 『右に』,右側に,右方に
《補語にのみ用いて》(道徳的に)『正しい』,正当な,正義の(just) / (人,人の判断・意見などが)『間偉いのない』,正しい(correct) / (事実に合って)『正しい』,正確な / 適切な,ぴったりの / (精神が)健全な,まともな;(心身が)健康な / 表の,正面の / 〈U〉(道徳的な)『正しさ』,正義;正しい行い / 〈C〉〈U〉(法律上・道徳上の)権利 / 〈U〉〈C〉《複数形で》(政治的・社会的な)人権,権利 / 《話》『まっすぐに』;まともに(directly) / 《話》『きっかり』,ちょうど(exactly) / 正確に,間違いなく(correctly) / (道徳的に)正しく,公正に / すっかり,完全に(completely);ずっと(all the way) / 適切に,ふさわしく;都合よく,うまく / 《おもに米話》すぐに,ただちに / 《特定の称号に付けて》非常に(very) / …‘を'正しい位置(状態)に戻す,立ち直らせる,整とんする / 〈誤りなど〉‘を'正す
〈船〉‘を'艤装(ぎそう)する / (マストなどを)〈船〉‘に'つける《+『名』+『with』+『名』》;(マストに)〈帆〉‘を'つける《+『名』+『to』+『名』》 / …‘に'装備をつける;…‘を'装備する《+『up』+『名,』+『名』+『up』》 / 船の装備(帆装),艤装(ぎそう) / (特定の目的のための)道具,用具 / 《英話》衣服,服装(clothing)
〈他〉〈相場など〉を不正な手段であやつる
(古代ローマの住宅建築で)中央広間 / (心臓の)心房

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/09/23 14:17:05」(JST)

wiki en

The atrium (plural: atria) is one of the two blood collection chambers of the heart. It was previously called the auricle, but that name has now been in use as being synonymous with the right or left atrial appendage.^[1] The atrium is a chamber in which blood enters the heart, as opposed to the ventricle, where it is pushed out of the organ. It has a thin-walled structure that allows blood to return to the heart. There is at least one atrium in animals with a closed circulatory system.

The atrium receives blood as it returns to the heart to complete a circulating cycle, whereas the ventricle pumps blood out of the heart to start a new cycle.^[2]^[3]

Structure

Right heart anatomy

left atrial appendage shown at upper right

Humans have a four-chambered heart consisting of the right atrium, left atrium, right ventricle, and left ventricle. The atria, are the two upper chambers. The right atrium receives and holds deoxygenated blood from the superior vena cava, inferior vena cava, anterior cardiac veins and smallest cardiac veins and the coronary sinus, which it then sends down to the right ventricle (through the tricuspid valve) which in turn sends it to the pulmonary artery for pulmonary circulation. The left atrium receives the oxygenated blood from the left and right pulmonary veins, which it pumps to the left ventricle (through the mitral valve) for pumping out through the aorta for systemic circulation.^[3]^[4]

The right atrium and right ventricle are often referred to as the right heart and similarly the left atrium and left ventricle are often referred to as the left heart. The atria do not have valves at their inlets ^[5] and as a result, a venous pulsation is normal and can be detected in the jugular vein as the jugular venous pressure.^[6]^[7] Internally, there are the rough pectinate muscles and crista terminalis of His, which act as a boundary inside the atrium and the smooth walled part of the right atrium, the sinus venarum derived from the sinus venosus. The sinus venarum is the adult remnant of the sinus venous and it surrounds the openings of the venae cavae and the coronary sinus. ^[8] Attached to the right atrium is the right atrial appendage – a pouch-like extension of the pectinate muscles. The interatrial septum separates the right atrium from the left atrium and this is marked by a depression in the right atrium –the fossa ovalis. The atria are depolarised by calcium.

High in the upper part of the left atrium is a muscular ear-shaped pouch –the left atrial appendage. This appears to "function as a decompression chamber during left ventricular systole and during other periods when left atrial pressure is high".^[9]

Nodes

The sinoatrial (SA) node is located in the right atrium, next to the superior vena cava. This is a group of pacemaker cells which spontaneously depolarize to create an action potential. The cardiac action potential then spreads across both atria causing them to contract, forcing the blood they hold into their corresponding ventricles.

The atrioventricular node (AV node) is another node in the cardiac electrical conduction system. This is located between the atria and the ventricles.

Development

During embryogenesis at about two weeks, a primitive atrium begins to be formed. It begins as one chamber which over the following two weeks becomes divided by the septum primum into the left atrium and the right atrium. The interatrial septum has an opening in the right atrium, the foramen ovale which provides access to the left atrium; this connects the two chambers, which is essential for fetal blood circulation. At birth, when the first breath is taken fetal blood flow is reversed to travel through the lungs. The foramen ovale is no longer needed and it closes to leave a depression (the fossa ovalis) in the atrial wall.

In some cases, the foramen ovale fails to close. This abnormality is present in approximately 25% of the general population.^[10] This is known as a patent foramen ovale, an atrial septal defect. It is mostly unproblematic, although it can be associated with paradoxical embolization and stroke.^[10]

Within the fetal right atrium, blood from the inferior vena cava and the superior vena cava flow in separate streams to different locations in the heart, and this has been reported to occur through the Coandă effect.^[11]

Function

In human physiology, the atria facilitate circulation primarily by allowing uninterrupted venous flow to the heart during ventricular systole.^[12]^[13] By being partially empty and distensible, atria prevent the interruption of venous flow to the heart that would occur during ventricular systole if the veins ended at the inlet valves of the heart. In normal physiologic states, the output of the heart is pulsatile, and the venous inflow to the heart is continuous and non-pulsatile. But without functioning atria, venous flow becomes pulsatile, and the overall circulation rate decreases significantly.^[14]^[15]

Atria have four essential characteristics that cause them to promote continuous venous flow. (1) There are no atrial inlet valves to interrupt blood flow during atrial systole. (2) The atrial systole contractions are incomplete and thus do not contract to the extent that would block flow from the veins through the atria into the ventricles. During atrial systole, blood not only empties from the atria to the ventricles, but blood continues to flow uninterrupted from the veins right through the atria into the ventricles. (3) The atrial contractions must be gentle enough so that the force of contraction does not exert significant back pressure that would impede venous flow. (4) The "let go" of the atria must be timed so that they relax before the start of ventricular contraction, to be able to accept venous flow without interruption.^[13]^[16]

By preventing the inertia of interrupted venous flow that would otherwise occur at each ventricular systole, atria allow approximately 75% more cardiac output than would otherwise occur. The fact that atrial contraction is 15% of the amount of the succeeding ventricular ejection has led to a misplaced emphasis on their role in pumping up the ventricles (the so-called "atrial kick"), whereas the key benefit of atria is in preventing circulatory inertia and allowing uninterrupted venous flow to the heart.^[13]^[17]

Also, of importance in maintaining the blood flow are the presence of atrial volume receptors. These are low-pressure baroreceptors in the atria, which send signals to the hypothalamus when a drop in atrial pressure (which indicates a drop in blood volume) is detected. This triggers a release of vasopressin.^[18]

Blood supply

The left atrium is supplied mainly by the left circumflex coronary artery, and its small branches.^[19]

The oblique vein of the left atrium is partly responsible for venous drainage; it derives from the embryonic left superior vena cava.

Clinical significance

In an adult, an atrial septal defect would result in the flow of blood in the reverse direction - from the left atrium to the right - which will reduce cardiac output, potentially causing cardiac failure and in severe or untreated cases cardiac arrest and sudden death.

In patients with atrial fibrillation, mitral valve disease, and other conditions, blood clots have a tendency to form in the LAA.^[9] Blood clots caused by atrial fibrillation stem from the LAA in more than 90% of cases.^[20] They may dislodge (forming emboli), which may lead to ischemic damage to the brain, kidneys, or other organs supplied by the systemic circulation.^[21] Left atrial appendage occlusion is an experimental treatment to prevent stroke in atrial fibrillation.^[22]

The left atrial appendage can serve as an approach for mitral valve surgery.^[23] The left atrial appendage can be seen on a standard posteroanterior x-ray, where the lower level of the left hilum becomes concave.^[24]

Wolff-Parkinson-White syndrome
Atrial flutter
Atrial tachycardia
Sinus tachycardia
Multifocal atrial tachycardia - several types
Premature atrial contraction
Atriomegaly

Other animals

Many other animals, including mammals, also have four-chambered hearts, which have a similar function. Some animals (amphibians and reptiles) have a three-chambered heart, in which the blood from each atrium is mixed in the single ventricle before being pumped to the aorta. In these animals, the left atrium still serves the purpose of collecting blood from the pulmonary veins.

In fish, the circulatory system is very simple: a two-chambered heart including one atrium and one ventricle. In other vertebrate groups, the circulatory system is much more complicated. Their circulatory systems are divided into two types: a three-chambered heart, with two atria and one ventricle, or a four-chambered heart, with two atria and two ventricles.

References

^ http://www.drugs.com/dict/auricles-of-atria.html
^ http://www.healthsystem.virginia.edu/uvahealth/adult_cardiac/anatomy.cfm
^ ^a ^b http://www.ivy-rose.co.uk/HumanBody/Blood/Heart_Structure.php
^ Human heart anatomy diagram. Retrieved on 2010-07-02.
^ http://www.americanheart.org/presenter.jhtml?identifier=4598
^ http://www.patient.info/doctor/Jugular-Venous-Pressure.htm
^ http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&part=A622#A629
^ http://www.med.unc.edu/embryo_images/unit-cardev/cardev_htms/cardev040.htm
^ ^a ^b Al-Saady NM et al (1999) Left atrial appendage: structure, function, and role in thromboembolism: Review Heart 82:547-554
^ ^a ^b Homma, S. (2005). "Patent Foramen Ovale and Stroke". Circulation 112 (7): 1063–1072. doi:10.1161/CIRCULATIONAHA.104.524371. ISSN 0009-7322.
^ Ashrafian H. The Coanda effect and preferential right atrial streaming. Chest. 2006 Jul;130(1):300.
^ Anderson, RM. The Gross Physiology of the Cardiovascular System (2nd ed., 2012). See "Chapter 1: Normal Physiology."
^ ^a ^b ^c Anderson, R.M., Fritz, J.M., and O’Hare, J.E. “The Mechanical Nature of the Heart as a Pump.” American Heart Journal 73 (1967): 92-105.
^ The Determinants of Cardiac Output (video produced by University of Arizona Biomedical Communications; demonstration of atrial effect begings at 13:43).
^ http://cardiac-output.info (See discussion of atrial effect in text Chapter 1.)
^ Anderson, RM. The Gross Physiology of the Cardiovascular System (2nd ed.) See "Chapter 1: Normal Physiology."
^ The Gross Physiology of the Cardiovascular System at 11.
^ Sherwood, Lauralee (2008). Human physiology: From cells to systems (7th revised ed.). Cengage Learning. p. 567. ISBN 978-0-495-39184-5. CS1 maint: Extra text (link)
^ Agur, Keith L. Moore, Arthur F. Dalley, Anne M.R. (2010). Clinically oriented anatomy (6th ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. p. 145. ISBN 9780781775250.
^ Blackshear JL, Odell JA (February 1996). "Appendage obliteration to reduce stroke in cardiac surgical patients with atrial fibrillation". Ann. Thorac. Surg. 61 (2): 755–9. doi:10.1016/0003-4975(95)00887-X. PMID 8572814.
^ Parekh A, Jaladi R, Sharma S, Van Decker WA, Ezekowitz MD (September 2006). "Images in cardiovascular medicine. The case of a disappearing left atrial appendage thrombus: direct visualization of left atrial thrombus migration, captured by echocardiography, in a patient with atrial fibrillation, resulting in a stroke". Circulation 114 (13): e513–4. doi:10.1161/CIRCULATIONAHA.106.617886. PMID 17000914.
^ Stöllberger C, Schneider B, Finsterer J (December 2003). "Elimination of the left atrial appendage to prevent stroke or embolism? Anatomic, physiologic, and pathophysiologic considerations". Chest 124 (6): 2356–62. doi:10.1378/chest.124.6.2356. PMID 14665520.
^ Guhathakurta S, Kurian VM, Manmohan, Cherian KM (2004). "Mitral valve reoperation through the left atrial appendage in a patient with mesocardia". Tex Heart Inst J 31 (3): 316–8. PMC 521780. PMID 15562857.
^ Corne et al. (2002). Chest X-Ray Made Easy. Churchill Livingstone. ISBN 0-443-07008-3.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 心耳の心エコー評価 echocardiographic evaluation of the atria and appendages
2. 心臓カテーテル検査法：正常な血行動態 cardiac catheterization techniques normal hemodynamics
3. 右心の心エコー評価 echocardiographic assessment of the right heart
4. 頚静脈波の検討 examination of the jugular venous pulse
5. 心臓カテーテル検査で測定した弁膜疾患の血行動態 hemodynamics of valvular disorders as measured by cardiac catheterization

English Journal

Change of right heart size and function by long-term therapy with riociguat in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension.

Marra AM1, Egenlauf B2, Ehlken N2, Fischer C3, Eichstaedt C2, Nagel C2, Bossone E4, Cittadini A5, Halank M6, Gall H7, Olsson KM8, Lange TJ9, Grünig E10.
International journal of cardiology.Int J Cardiol.2015 Sep 15;195:19-26. doi: 10.1016/j.ijcard.2015.05.105. Epub 2015 May 19.
BACKGROUND: Riociguat is a soluble guanylate cyclase stimulator approved for pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). The objective of this study was to evaluate the change of right heart size and function assessed by echocardiography during lo
PMID 26011408

Expression and function of Kv1.1 potassium channels in human atria from patients with atrial fibrillation.

Glasscock E1, Voigt N, McCauley MD, Sun Q, Li N, Chiang DY, Zhou XB, Molina CE, Thomas D, Schmidt C, Skapura DG, Noebels JL, Dobrev D, Wehrens XH.
Basic research in cardiology.Basic Res Cardiol.2015 Sep;110(5):505. doi: 10.1007/s00395-015-0505-6. Epub 2015 Jul 11.
Voltage-gated Kv1.1 channels encoded by the Kcna1 gene are traditionally regarded as being neural-specific with no known expression or intrinsic functional role in the heart. However, recent studies in mice reveal low-level Kv1.1 expression in heart and cardiac abnormalities associated with Kv1.1-de
PMID 26162324

Altered expression of hyperpolarization-activated cyclic nucleotide-gated channels and microRNA-1 and -133 in patients with age-associated atrial fibrillation.

Li YD1, Hong YF1, Yusufuaji Y1, Tang BP1, Zhou XH1, Xu GJ1, Li JX1, Sun L1, Zhang JH1, Xin Q1, Xiong J1, Ji YT1, Zhang Y1.
Molecular medicine reports.Mol Med Rep.2015 Sep;12(3):3243-8. doi: 10.3892/mmr.2015.3831. Epub 2015 May 25.
Hyperpolarization-activated cyclic nucleotide-gated (HCN) cation channels mediate pacemaker currents in the atrium. The microRNA (miR) families miR-1 and miR-133 regulate the expression of multiple genes involved in myocardial function, including HCN channels. It was hypothesized that age‑dependen
PMID 26005035

Japanese Journal

大腿静脈に留置した中心静脈カテーテル抜去後に右房流入部まで伸展した下大静脈血栓を摘出された糖尿病ケトアシドーシスの1症例

森田蓉子,有山淳,三枝勉 [他]
麻酔 63(5), 564-567, 2014-05
NAID 40020086036

臨床経験心タンポナーデで発症した原発性心臓血管肉腫

久貝忠男,摩文仁克人,盛島裕次 [他]
胸部外科 = The Japanese journal of thoracic surgery 67(2), 125-129, 2014-02
NAID 40019953529

Uterine Intravenous Leiomyomatosis with Right Ventricular Extension

Sogabe Masaya,Kawahito Koji,Aizawa Kei,Sato Hirotaka,Misawa Yoshio
Annals of Thoracic and Cardiovascular Surgery, 2014
… Computed tomography indicated the presence of an intravenous leiomyoma originating from the uterus and extending to the inferior vena cava, right atrium, and right ventricle. …
NAID 130003396743

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★リンクテーブル★

リンク元	「右心房」「RA」「heart atria」「heart atrium」「right-atrial」
関連記事	「right」「atrium」「rig」

「右心房」

Atrium
	Front view of heart showing the atria
Details
Latin	Atrium
Identifiers
Gray's	p.528
TA	A12.1.00.017
FMA	7099
	Anatomical terminology

　　[★]

英: right atrium (Z) RA, right atrium of heart
ラ: atrium dextrum
同: 右房
関: 左心房、右心室、心房、心室

[show details]

右房 : 約 94,400 件
右心房 : 約 100,000 件

「RA」

　　[★]

「heart atria」

　　[★]

心房

関: atria、atrial、atrium、heart atrium、left atrium、right atrium

「heart atrium」

　　[★]

心房

関: atria、atrial、atrium、heart atria、left atrium、right atrium

「right-atrial」

　　[★]

右心房の

関: right atria、right atrium

「right」

　　[★]

n.

右、権利

adj.

正しい、右位の、直角の

関: correct、dexter、dextroposition、fair、human right、rectangular、right angle

「atrium」

　　[★]

adj.

心房

「rig」

　　[★] 　　　　　　　　

[1] ttp://www.drugs.com/dict/auricles-of-atria.html

[2] ttp://www.healthsystem.virginia.edu/uvahealth/adult_cardiac/anatomy.cfm

[ivy-rose.co.uk-3] ttp://www.ivy-rose.co.uk/HumanBody/Blood/Heart_Structure.php

[4] Human heart anatomy diagram. Retrieved on 2010-07-02.

[5] ttp://www.americanheart.org/presenter.jhtml?identifier=4598

[6] ttp://www.patient.info/doctor/Jugular-Venous-Pressure.htm

[7] ttp://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&part=A622#A629

[8] ttp://www.med.unc.edu/embryo_images/unit-cardev/cardev_htms/cardev040.htm

[Al-Saady-9] Al-Saady NM et al (1999) Left atrial appendage: structure, function, and role in thromboembolism: Review Heart 82:547-554

[Homma2005-10] Homma, S. (2005). "Patent Foramen Ovale and Stroke". Circulation 112 (7): 1063–1072. doi:10.1161/CIRCULATIONAHA.104.524371. ISSN 0009-7322.

[11] Ashrafian H. The Coanda effect and preferential right atrial streaming. Chest. 2006 Jul;130(1):300.

[12] Anderson, RM. The Gross Physiology of the Cardiovascular System (2nd ed., 2012). See "Chapter 1: Normal Physiology."

[cardiac-output.info-13] Anderson, R.M., Fritz, J.M., and O’Hare, J.E. “The Mechanical Nature of the Heart as a Pump.” American Heart Journal 73 (1967): 92-105.

[14] The Determinants of Cardiac Output (video produced by University of Arizona Biomedical Communications; demonstration of atrial effect begings at 13:43).

[15] ttp://cardiac-output.info (See discussion of atrial effect in text Chapter 1.)

[16] Anderson, RM. The Gross Physiology of the Cardiovascular System (2nd ed.) See "Chapter 1: Normal Physiology."

[17] The Gross Physiology of the Cardiovascular System at 11.

[18] Sherwood, Lauralee (2008). Human physiology: From cells to systems (7th revised ed.). Cengage Learning. p. 567. ISBN 978-0-495-39184-5. CS1 maint: Extra text (link)

[19] Agur, Keith L. Moore, Arthur F. Dalley, Anne M.R. (2010). Clinically oriented anatomy (6th ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. p. 145. ISBN 9780781775250.

[pmid8572814-20] Blackshear JL, Odell JA (February 1996). "Appendage obliteration to reduce stroke in cardiac surgical patients with atrial fibrillation". Ann. Thorac. Surg. 61 (2): 755–9. doi:10.1016/0003-4975(95)00887-X. PMID 8572814.

[pmid17000914-21] Parekh A, Jaladi R, Sharma S, Van Decker WA, Ezekowitz MD (September 2006). "Images in cardiovascular medicine. The case of a disappearing left atrial appendage thrombus: direct visualization of left atrial thrombus migration, captured by echocardiography, in a patient with atrial fibrillation, resulting in a stroke". Circulation 114 (13): e513–4. doi:10.1161/CIRCULATIONAHA.106.617886. PMID 17000914.

[Stollberger2003-22] Stöllberger C, Schneider B, Finsterer J (December 2003). "Elimination of the left atrial appendage to prevent stroke or embolism? Anatomic, physiologic, and pathophysiologic considerations". Chest 124 (6): 2356–62. doi:10.1378/chest.124.6.2356. PMID 14665520.

[pmid15562857-23] Guhathakurta S, Kurian VM, Manmohan, Cherian KM (2004). "Mitral valve reoperation through the left atrial appendage in a patient with mesocardia". Tex Heart Inst J 31 (3): 316–8. PMC 521780. PMID 15562857.

[24] Corne et al. (2002). Chest X-Ray Made Easy. Churchill Livingstone. ISBN 0-443-07008-3.

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right atrium