WordNet

relating to or associated with the bronchi; "bronchial tubes"; "bronchial pneumonia"

PrepTutorEJDIC

bronchusの複数形
気管支の

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/10/30 17:25:21」(JST)

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A bronchus, also known as a main or primary bronchus, is a passage of airway in the respiratory tract that conducts air into the lungs. There is a right bronchus and a left bronchus and these bronchi branch into smaller secondary and tertiary bronchi which branch into smaller tubes, known as bronchioles.^[1] No gas exchange takes place in the bronchi.

Structure

The trachea (windpipe) divides into two main or primary bronchi, the left and the right, at the level of the sternal angle and of the fifth thoracic vertebra or up to two vertebrae higher or lower, depending on breathing, at the anatomical point the carina of trachea.

The right main bronchus is wider, shorter, and more vertical than the left main bronchus.^[2]It enters the right lung at approximately the fifth thoracic vertebra. The right main bronchus subdivides into three secondary bronchi (also known as lobar bronchi), which deliver oxygen to the three lobes of the right lung—the superior, middle and inferior lobe. The azygos vein arches over it from behind; and the right pulmonary artery lies at first below and then in front of it. About 2 cm from its commencement it gives off a branch to the superior lobe of the right lung, which is also called the eparterial bronchus. Eparterial refers to its position above the right pulmonary artery. The right bronchus now passes below the artery, and is known as the hyparterial branch which divides into the two lobar bronchi to the middle and lower lobes.

The left main bronchus is smaller in caliber but longer than the right, being 5 cm long. It enters the root of the left lung opposite the sixth thoracic vertebra. It passes beneath the aortic arch, crosses in front of the esophagus, the thoracic duct, and the descending aorta, and has the left pulmonary artery lying at first above, and then in front of it. The left bronchus has no eparterial branch, and therefore it has been supposed by some that there is no upper lobe to the left lung, but that the so-called upper lobe corresponds to the middle lobe of the right lung. The left main bronchus divides into two secondary or lobar bronchi to deliver air to the two lobes of the left lung—the superior and the inferior lobe.

The secondary bronchi divide further into tertiary bronchi, (also known as segmental bronchi), each of which supplies a bronchopulmonary segment. A bronchopulmonary segment is a division of a lung separated from the rest of the lung by a septum of connective tissue. This property allows a bronchopulmonary segment to be surgically removed without affecting other segments. Initially, there are ten segments in each lung, but during development with the left lung having just two lobes, two pairs of segments fuse to give eight, four for each lobe. The tertiary bronchi divide into many smaller bronchioles which divide into terminal bronchioles, each of which then gives rise to several respiratory bronchioles, which go on to divide into two to eleven alveolar ducts. There are five or six alveolar sacs associated with each alveolar duct. The alveolus is the basic anatomical unit of gas exchange in the lung.

The main bronchi have relatively large lumens that are lined by respiratory epithelium. This cellular lining has cilia departing towards the mouth which removes dust and other small particles. There is a smooth muscle layer below the epithelium arranged as two ribbons of muscle that spiral in opposite directions. This smooth muscle layer contains seromucous glands, which secrete musus, in its wall. Hyaline cartilage is present in the bronchi, surrounding the smooth muscle layer. In the main bronchi, hyaline cartilage forms an incomplete ring, giving a "D"-shaped appearance, while in the smaller bronchi, hyaline cartilage is present in irregularly arranged plates and islands. These plates give structural support to the bronchi and keep the airway open.

Histology

Pseudostratified columnar ciliated epithelium - mag. x600

Cross section of secondary bronchus

The cartilage and mucous membrane of the primary bronchi are similar to those in the trachea. They are lined with respiratory epithelium, which is classified as ciliated pseudostratified columnar epithelium.^[3] The epithelium in the main bronchi contains goblet cells, which are glandular, modified simple columnar epithelial cells that produce mucins, the main component of mucus. Mucus plays an important role in keeping the airways clear via the mucociliary escalator. As branching continues through the bronchial tree, the amount of hyaline cartilage in the walls decreases until it is absent in the bronchioles. As the cartilage decreases, the amount of smooth muscle increases. The mucous membrane also undergoes a transition from ciliated pseudostratified columnar epithelium to simple cuboidal epithelium to simple squamous epithelium.^[3]

Variation

In 0.1 to 5% of people there is a right superior lobe bronchus arising from the main stem bronchus prior to the carina. This is known as a tracheal bronchus, and seen as an anatomical variation. It can have multiple variations and, although usually asymptomatic, it can be the root cause of pulmonary disease such as a recurrent infection. In such cases resection is often curative^[4] ^[5]

The cardiac bronchus has a prevalence of ~0.3% and presents as an accessory bronchus arising from the bronchus intermedius between the upper lobar bronchus and the origin of the middle and lower lobar bronchi of the right main bronchus.^[6] Accessory cardiac bronchus is usually an asymptomatic condition but may be associated with persistent infection or hemoptysis.^[7]^[8] In about half of observed cases the cardiac bronchus presents as a short dead ending bronchial stump, in the remainder the bronchus may exhibit branching and associated aerated lung parenchyma.

Function

The alveolar ducts and alveoli consist primarily of simple squamous epithelium, which permits rapid diffusion of oxygen and carbon dioxide. Exchange of gases between the air in the lungs and the blood in the capillaries occurs across the walls of the alveolar ducts and alveoli.

Clinical significance

Bronchitis

Bronchitis is defined as inflammation of the bronchi, which can either be acute or chronic. Acute bronchitis is usually caused by viral or bacterial infections. Most sufferers of chronic bronchitis also suffer from chronic obstructive pulmonary disease (COPD), and is usually associated with smoking or long-term exposure to irritants.

Aspiration

While the left mainstem bronchus departs from the trachea at an angle, the right mainstem bronchus is almost a vertical continuation of the trachea. This anatomy predisposes the right lung to several problems:

If food, liquids, or foreign bodies are aspirated, they often will lodge in the right mainstem bronchus. Aspiration pneumonia may result.
If the endotracheal tube used for intubation is inserted too far, it usually lodges in the right mainstem bronchus. This allows ventilation of the right lung, but leaves the left lung useless.

Asthma

Asthma is hyperreactivity of the bronchi with an inflammatory component, often in response to allergens.

In asthma, the constriction of the bronchi can result in a difficulty in breathing giving shortness of breath; this can lead to a lack of oxygen reaching the body for cellular processes. In this case an asthma puffer can be used to rectify the problem. The puffer administers a bronchodilator, which serves to soothe the constricted bronchi and to re-expand the airways. This effect occurs quite quickly.

Additional images

Transverse section of thorax, showing relations of pulmonary artery
Illustration depicting respiratory system
Mainstem bronchi seen branching off the trachea (labeled at top), with the left mainstem bronchi passing below the aortic arch before branching into smaller bronchi.

References

^ Maton, Anthea; Jean Hopkins; Charles William McLaughlin; Susan Johnson; Maryanna Quon Warner; David LaHart; Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN 0-13-981176-1. ^{[page needed]}
^ Brodsky, JB; Lemmens, JM (2003). "Left Double-Lumen Tubes: Clinical Experience With 1,170 Patients" (PDF). Journal of Cardiothoracic and Vascular Anesthesia 17 (3): 289–98. doi:10.1016/S1053-0770(03)00046-6. PMID 12827573.
^ ^a ^b Marieb, Elaine N.; Hoehn, Katja (2012). Human Anatomy & Physiology (9th ed.). Pearson. ISBN 0321852125.
^ Shih, Fu-Chieh; Wei-Jing Lee; Hung-Jung Lin (2009-03-31). "Tracheal bronchus". Canadian Medical Association Journal 180 (7): 783–783. doi:10.1503/cmaj.080280. ISSN 0820-3946.
^ Barat, Michael; Horst R. Konrad (1987-03-04). "Tracheal bronchus". American Journal of Otolaryngology 8 (2): 118–122. doi:10.1016/S0196-0709(87)80034-0. ISSN 0196-0709. Retrieved 2011-05-17.
^ "Cardiac bronchus". Radiopedia. Archived from the original on 2015-10-26.
^ Parker MS, Christenson ML, Abbott GF. Teaching atlas of chest imaging. 2006, ISBN 3131390212
^ McGuinness G, Naidich DP, Garay SM, Davis AL, Boyd AD, Mizrachi HH (1993). "Accessory cardiac bronchus: CT features and clinical significance". Radiology 189 (2): 563–6. doi:10.1148/radiology.189.2.8210391. PMID 8210391.

Sources

Sacristán Bou, L. and Peña Blas, F. Bronchial Atresia in Lung Diseases - Selected State of the Art Reviews (2012). ISBN 978-953-51-0180-2. Published under CC BY 3.0 license.
Moore, Keith L. and Arthur F. Dalley. Clinically Oriented Anatomy, 4th ed. (1999). ISBN 0-7817-5936-6

External links

American Lung Association

Anatomy figure: 19:08-03 at Human Anatomy Online, SUNY Downstate Medical Center - "The divisions of the bronchus."

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. 成人における急性気管支炎 acute bronchitis in adults
2. 縦隔リンパ節腫脹の外科的マネージメント surgical management of mediastinal lymphadenopathy
3. 小児における喘息以外の喘鳴疾患 wheezing illnesses other than asthma in children
4. 硬性気管支鏡：装置の概要 rigid bronchoscopy instrumentation
5. 肺結核の臨床症状および評価 clinical manifestations and evaluation of pulmonary tuberculosis

English Journal

Exposure to Traffic-Related Air Pollutants as a Risk of Airway Obstruction.

Badyda AJ, Dabrowiecki P, Lubinski W, Czechowski PO, Majewski G.SourceFaculty of Environmental Engineering, Warsaw University of Technology, Nowowiejska 20 St, 00-653, Warsaw, Poland, artur.badyda@is.pw.edu.pl.
Advances in experimental medicine and biology.Adv Exp Med Biol.2013;755:35-45.
Dynamic increases in the number of vehicles, particularly in large urban areas, cause a visible decline in the average speed of cars. Street networks are not able to efficiently handle generated traffic, which could result in increasing levels of air pollutant emissions and consequently in a greater
PMID 22826047

Virtual 3-D (18)F-FDG PET/CT panendoscopy for assessment of the upper airways of head and neck cancer patients: a feasibility study.

Buchbender C, Treffert J, Lehnerdt G, Mattheis S, Geiger B, Bockisch A, Forsting M, Antoch G, Heusner TA.SourceMedical Faculty, Department of Diagnostic and Interventional Radiology, University Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Germany.
European journal of nuclear medicine and molecular imaging.Eur J Nucl Med Mol Imaging.2012 Sep;39(9):1435-40. Epub 2012 Jun 5.
PURPOSE: The aim of this study was to evaluate whether a virtual 3-D (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT panendoscopy is feasible and can be used for noninvasive imaging of the upper airways and pharyngeal/laryngeal tumours.METHODS: From (18)F-FDG PET/CT data sets of
PMID 22669254

Japanese Journal

心膜と肋間筋弁を用いて気管支断端パッチ閉鎖術を施行した肺癌の1例

太田安彦,鈴木光隆,常塚宣男
気管支学 : 日本気管支研究会雑誌 34(2), 144-147, 2012-03-25
背景.気管支レベルでのパッチ閉鎖術の報告は極めて少ない.症例.67歳.男性.左肺下葉に5cm大の腫瘤陰影を認め,気管支鏡下生検にて腺癌の診断が得られた.葉気管間および気管支周囲リンパ節に転移がみられ,下葉支から上・下幹分岐部に浸潤を認めた.下葉切除と徹底したリンパ節郭清を行った後,気管支を形成・トリミングし心膜を用いたパッチ閉鎖と有茎肋間筋弁による被覆を施行した.術後は合併症なく順調に経過し,術後 …
NAID 110009437395

内視鏡外科手術における研究と治療の進歩(1)胸部外科領域,胸腔鏡下手術

神崎正人
東京女子医科大学雑誌 82(1), 8-15, 2012-02-25
1990年頃から胸腔鏡下手術が始まった.当初、VATS=Video-assisted thoracic surgeryで、胸腔鏡補助手術であったが、現在VATSは、Video-assisted thoracoscopic surgeryになっている. 大別すると、1.完全胸腔鏡下手術、2.ポートアクセスVATS、3.小開胸直視併用の従来のVATSとなる.当科では、 1992年より胸腔鏡を導入した. …
NAID 110008802809

Related Pictures

★リンクテーブル★

リンク元	「100Cases 33」「気管支」
拡張検索	「bronchial」「bronchial tube」「intrabronchial」

「100Cases 33」

Bronchus
	Conducting passages.
	Front view of cartilages of larynx, trachea and bronchi.
Details
Latin	Bronchus
System	Respiratory system
Artery	Bronchial artery
Vein	Bronchial vein
Nerve	Pulmonary branches of vagus nerve
Identifiers
Gray's	p.1084
MeSH	A04.411.125
Dorlands; /Elsevier	b_23/12198294
TA	A06.4.01.001
FMA	70774
	Anatomical terminology

　　[★]

☆case33　頭痛と混乱

■glossary

accompany

vt.

(人)と同行する、(人)に随行する。(もの)に付随する。～と同時に起こる。～に加える(添える、同封する)(with)

slurred n. 不明瞭

強直間代痙攣 tonic-clonic convulsion

　意識消失とともに全身の随意筋に強直痙攣が生じ(強直痙攣期tonic convulsion)、次いで全身の筋の強直と弛緩とが律動的に繰り返される時期(間代痙攣期clonic convulsion)を経て、発作後もうろう状態を呈する一連の発作。

■症例

28歳、女性　黒人　南アフリカ　手術室看護師　ロンドン住在

主訴：頭痛と混乱

現病歴：過去3週間で頭痛が続いており、ひどくなってきた。現在も頭痛が持続しており、頭全体が痛い。友人曰く「過去六ヶ月で体重が10kg減っていて、最近、混乱してきたようだ」。発話は不明瞭。救急室にいる間に強直間代痙攣を起こした。

・診察 examination

やせている。55kg。38.5℃。口腔カンジダ症(oral candidiasis)。リンパ節腫脹無し。心血管、呼吸器系、消化器系正常。痙攣前における神経検査では時間、場所、人の見当識無し。神経局所症状無し(no focal neurological sign)。眼底両側に乳頭浮腫有り。

・検査 investigation

血算：白血球増多

血液生化学：ナトリウム低下

CT：供覧

■キーワード＆着目するポイント

・口腔カンジダ症(oral candidiasis)

・頭痛、精神症状、強直間代痙攣

・眼底両側に乳頭浮腫

・CT 所見

・低ナトリウム血症は二次的なもの

■アプローチ

・口腔カンジダ症(oral candidiasis)　→　細胞免疫低下状態(DM、免疫抑制、AIDSなど) or 常在細菌叢の攪乱(長期の抗菌薬の使用)

　・The occurrence of thrush in a young, otherwise healthy-appearing person should prompt an investigation for underlying HIV infection.(HIM.1254)

　・More commonly, thrush is seen as a nonspecific manifestation of severe debilitating illness.(HIM.1254)

・精神症状、強直間代痙攣　→　一次的、あるいは二次的な脳の疾患がありそう

・頭痛　→　漠然としていて絞れないが、他の症状からして機能性頭痛ではなく症候性頭痛っぽい。

・眼底両側に乳頭浮腫　→　脳圧亢進の徴候　→　原因は・・・脳腫瘍、ことにテント下腫瘍と側頭葉の腫瘍、クモ膜下出血、脳水腫など、そのほか、眼窩内病変、低眼圧などの局所的要因、悪性高血圧、血液疾患、大量出血、肺気腫などの全身的要因 (vindicate本のp342も参考になる)

　・頭痛と脳圧亢進　→　頭蓋内圧占拠性病変、脳炎(IMD.274)

・CT 所見　→　ringformの病変、脳浮腫、脳圧亢進

・低ナトリウム血症　→　脳ヘルニアに続発して起こることがあるらしい。実際には下垂体にトキソプラズマによる病変が形成されることにより起こりうる。

・そのほか出身地、体重減少もHIVを疑わせる点

パターン認識でHIV + 精神症状 + てんかん発作(強直間代痙攣) + 脳圧亢進 + CT 所見 = 一番ありそうなのはToxoplasma gondiiによるトキソプラズマ脳症 cerebral toxoplasosis (トキソプラズマ脳炎 toxoplasmic encephalitis)

■Toxoplasma gondii

　原虫　胞子原虫類

(感染予防学 080521のプリント、CASES p,92、HIM p.1305-)

・疫学：西洋では30-80%の成人がトキソプラズマの感染の既往がある・・・うぇ(CASES)。日本では10%前後(Wikipedia)。

・生活環

　・終宿主：ネコ：ネコの小腸上皮細胞で有性・無性生殖　糞便にオーシストの排泄

　・中間宿主：ヒト.ブタを含むほ乳類と鳥類：無性生殖で増殖、シストの形成

　　　急性期の増殖盛んな急増虫体 tachyzoiteとシスト内の緩増虫体 bradyzoite

・病原、病因 phathogenesis

　・緩増虫体(bradyzoite)、接合子嚢(oocyst)

・感染経路

　1. オーシストの経口摂取

　2. 中間宿主の生肉中のシストの経口摂取

　3. 初感染妊婦からの経胎盤感染。既感染なら胎盤感染しないらしい(HIM.1306)

　(4)移植臓器、輸血。確率は低い(at low rate)(HIM.1306)

・病態

　1. 先天性トキソプラズマ症　congenital toxoplasmosis

　　　①網脈絡膜炎、 ②水頭症、 ③脳内石灰化、 ④精神・運動障害

　2. 後天性トキソプラズマ症　acquired toxoplasmosis

　　(1) 健常者

　　　・多くは不顕性感染。発熱、リンパ節腫脹、皮疹(rash)

　　　・(少数例)筋肉痛、暈疼痛、腹痛、斑状丘疹状皮疹(maculopapular rash)、脳脊髄炎、混乱(HIM.1308)

　　　・(まれ)肺炎、心筋炎、脳症、心膜炎、多発筋炎

　　　・網膜、脈絡叢に瘢痕や、脳に小さい炎症性の病変を残すことあり(CASES)。

　　　・急性感染の症状は数週間で消失　筋肉や中枢神経系に緩増虫体が残存

　　(2)HIV 感染者、臓器移植例、がん化学療法例

　　　シスト内緩増虫体→急増虫体→播種性の多臓器感染

　　　AIDSでは、トキソプラズマ性脳炎が指標疾患 AIDS-defineing illness(CASES)

・治療

　(日本)アセチルスピラマイシン、ファンシダール(感染予防学 080521)

■トキソプラズマ脳炎 toxoplasmic encephalitis、トキソプラズマ脳症 cerebral toxoplasosis

・症状

　発熱、頭痛、混乱ｍ、痙攣、認知の障害、局所神経徴候(不全片麻痺、歯垢、脳神経損傷、視野欠損、感覚喪失)(CASES)

・画像検査

　(CT,MRI)多発性、両側性、ring-enhancing lesion、特に灰白質-白質境界、大脳基底核、脳幹、小脳が冒されやすい(CASES)

・鑑別診断(臨床症状・画像診断の所見で)

　リンパ腫、結核、転移性脳腫瘍(CASES)

・病歴と画像所見からの鑑別診断

　リンパ腫、結核、転移性腫瘍

？

このCTがcerebral toxoplasmosisに特徴的かは不明

□最後に残る疑問

　AIDSでWBC(leukocyte)の数はどうなるんだろう？？？AIDSの初診患者ではWBCが低い人が多いらしいし()、HIVはCD4+ T cellとmacrophageに感染して殺すから、これによってB cellは減るだろうし、CD8+ T cellも若干減少するだろうからWBCは減るんじゃないか？！好中球はAIDSとは関係ない？好中球は他の感染症に反応性に増加している？ちなみに、好酸球は寄生虫(原虫)の感染のために増える傾向にあるらしい(HIMのどこか)。

葉酸拮抗剤である。

サルファ剤と併用され、抗トキソプラズマ薬、抗ニューモシチス・カリニ薬として相乗的に働く。

ST 合剤

SMX-TMP

スルファメトキサゾール・トリメトプリム合剤 sulfamethoxazole and trimethoprim mixture

□AIDSの定義(http://en.wikipedia.org/wiki/CDC_Classification_System_for_HIV_Infection_in_Adults_and_Adolescents)

According to the US CDC definition, one has AIDS if he/she is infected with HIV and present with one of the following:

A CD4+ T-cell count below 200 cells/μl (or a CD4+ T-cell percentage of total lymphocytes of less than 14%).

or he/she has one of the following defining illnesses:

01. Candidiasis of bronchi, trachea, or lungs
02. Candidiasis esophageal
03. Cervical cancer (invasive)
04. Coccidioidomycosis, disseminated or extrapulmonary
05. Cryptococcosis, extrapulmonary
06. Cryptosporidiosis, chronic intestinal for longer than 1 month
07. Cytomegalovirus disease (other than liver, spleen or lymph nodes)
08. Encephalopathy (HIV-related)
09. Herpes simplex: chronic ulcer(s) (for more than 1 month); or bronchitis, pneumonitis, or esophagitis
10. Histoplasmosis, disseminated or extrapulmonary
11. Isosporiasis, chronic intestinal (for more than 1 month)
12. Kaposi's sarcoma
13. Lymphoma Burkitt's, immunoblastic or primary brain
14. Mycobacterium avium complex
15. Mycobacterium, other species, disseminated or extrapulmonary
16. Pneumocystis carinii pneumonia
17. Pneumonia (recurrent)
18. Progressive multifocal leukoencephalopathy
19. Salmonella septicemia (recurrent)
20. Toxoplasmosis of the brain
21. Tuberculosis
22. Wasting syndrome due to HIV

People who are not infected with HIV may also develop these conditions; this does not mean they have AIDS. However, when an individual presents laboratory evidence against HIV infection, a diagnosis of AIDS is ruled out unless the patient has not:

undergone high-dose corticoid therapy or other immunosuppressive/cytotoxic therapy in the three months before the onset of the indicator disease
OR been diagnosed with Hodgkin's disease, non-Hodgkin's lymphoma, lymphocytic leukemia, multiple myeloma, or any cancer of lymphoreticular or histiocytic tissue, or angioimmunoblastic lymphoadenopathy
OR a genetic immunodeficiency syndrome atypical of HIV infection, such as one involving hypogamma globulinemia

AND

the individual has had Pneumocystis carinii pneumonia
OR one of the above defining illnesses AND a CD4+ T-cell count below 200 cells/μl (or a CD4+ T-cell percentage of total lymphocytes of less than 14%).

□AIDSのステージング

Revised World Health Organization (WHO) Clinical Staging of HIV/AIDS For Adults and Adolescents (2005)

http://en.wikipedia.org/wiki/WHO_Disease_Staging_System_for_HIV_Infection_and_Disease_in_Adults_and_Adolescents

■参考文献

HIM = Harrison's Principles of Internal Medicine 17th Edition

CASES = 100 Cases in Clinical Medicine Second edition

IMD = 内科診断学第2版

「気管支」

　　[★]

英: bronchus / bronchi(pl.) (Z)
ラ: bronchus principalis
同: 主気管支 main bronchus、一次気管支 primary bronchus
関: 気管、気管支の分岐、肺区域、区域気管支

右主気管支

右上葉気管支
中間気管支幹

左主気管支

Henry Gray (1825-1861). Anatomy of the Human Body. 1918.
Henry Gray (1825-1861). Anatomy of the Human Body. 1918.
Henry Gray (1825-1861). Anatomy of the Human Body. 1918.