bronchus principalis dexter

右主気管支

WordNet

1. capital as contrasted with the income derived from it (同)corpus, principal sum
2. the original amount of a debt on which interest is calculated
3. the major party to a financial transaction at a stock exchange; buys and sells for his own account (同)dealer
4. the educator who has executive authority for a school; "she sent unruly pupils to see the principal" (同)school principal, head teacher, head
5. (criminal law) any person involved in a criminal offense, regardless of whether the person profits from such involvement
6. either of the two main branches of the trachea (同)bronchial_tube
7. on or starting from the wearers right

PrepTutorEJDIC

1. (重要性・地位・価値などが)『第1の』;おもな,主要な / 『長』,かしら;重要人物,主役 / 《しばしばP-》(小・中学校,高校の)『校長』;(特に《英》でcollegeの)学長,(時に)学寮長 / 《単数形で》(interest(利子),revenue(運用収益)と区別して)『元金』,基本財産
2. 気管支

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/07/06 14:44:36」(JST)

wiki en

[Wiki en表示]

Bronchus
Conducting passages.
Front view of cartilages of larynx, trachea and bronchi.
Latin	Bronchus
Gray's	p.1084
System	Respiratory system
Artery	Bronchial artery
Vein	Bronchial vein
Nerve	Pulmonary branches of vagus nerve
MeSH	Bronchi

A bronchus (plural bronchi, adjective bronchial), also known as a main or primary bronchus, is a passage of airway in the respiratory tract that conducts air into the lungs. The bronchus branches into smaller tubes, which in turn become bronchioles. 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.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 air to the three lobes of the right lung.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, the eparterial bronchus, to the upper lobe of the right lung. 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; it divides into two branches for 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 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 per 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 segmental 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 hyaline cartilage forms an incomplete ring in the bronchi, giving them a "D"-shaped appearance in the larger bronchi and as small plates and islands in the smaller bronchi. Smooth muscle is present continuously around the bronchi.

Histology

Main article: Respiratory epithelium

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. As the 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.

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

Function

See also: Respiratory tree

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

Main article: 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 is a broncho-dilator, which serves to soothe the constricted bronchi and to once again 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

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

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. 胸腔内気道の先天異常および気管食道瘻 congenital anomalies of the intrathoracic airways and tracheoesophageal fistula
• 2. 肺発達異常の放射線学的所見 radiographic appearance of developmental anomalies of the lung
• 3. 気管の放射線学 radiology of the trachea
• 4. 肺移植後の気道合併症 airway complications after lung transplantation
• 5. 肺の高分解能CT high resolution computed tomography of the lungs

English Journal

• Clinical image. Bronchus cardiacus accessorius dexter.

• Roebuck D, McLaren CA.SourceDepartment of Radiology, Great Ormond Street Hospital for Sick Children, Great Ormond Street, London WC1N 3JH, UK. roebud@gosh.nhs.uk
• Pediatric radiology.Pediatr Radiol.2010 Jul;40(7):1297. doi: 10.1007/s00247-009-1407-2. Epub 2009 Nov 17.
• PMID 19921169

• [Endobronchial drug administration in resuscitation].

• Sefrin P, Finkenzeller A.SourceInstitut für Anästhesiologie, Universität Würzburg.
• Medizinische Klinik (Munich, Germany : 1983).Med Klin (Munich).1991 Jan 15;86(1):20-3.
• The endobronchial application of drugs is recommended during pharmacological reanimation in lack of venous punction possibility. To find out the quantity of the area of resorption after deep endobronchial instillation twelve human corpses had been intubated and methylen-blue was applicated through t
• PMID 2017112

• Systemic arterial blood supply to the trachea and lung in sheep.

• Charan NB, Turk GM, Czartolomny J, Andreazuk T.AbstractWe studied the systemic arterial blood supply to the trachea and lung in adult sheep. After anesthesia, sheep were exsanguinated and then studied by intra-arterial injection of one of the following materials: saline containing dyes of various colors (n = 24), Microfil (n = 8), or Batson's solution (n = 6). The systemic blood supply to the cervical trachea originated from the two common carotid arteries via three to four small branches (rami tracheales cervicales) on each side. A segment of the thoracic trachea between the thoracic inlet and the origin of the tracheal bronchus (bronchus trachealis) and the bronchial tree of the right cranial lobe (lobus cranialis dexter) were supplied by the tracheal bronchial branch (ramus bronchalis trachealis), which originated from the brachiocephalic trunk (truncus brachiocephalicus). A portion of thoracic trachea between the origin of the tracheal bronchus and the tracheal carina was supplied by the thoracic tracheal branch (ramus trachealis thoracica), arising from the bronchoesophageal artery (arteria bronchoesophagea) or directly from the thoracic aorta. The bronchial branch (ramus bronchalis) originated from the bronchoesophageal artery, and its branches supplied the remainder of the bronchial tree. At 120 cmH2O pressure (n = 8), the bronchial branch contributed approximately 50% and the other two approximately 25% each of the total tracheobronchial blood flow. These three branches also supplied the visceral pleura. Additionally, several small vessels (rami pleurales pulmonales) originated from the esophageal branch (ramus esophagea) of the bronchoesophageal artery, traversed the pulmonary ligaments, and supplied the visceral pleura.
• Journal of applied physiology (Bethesda, Md. : 1985).J Appl Physiol.1987 Jun;62(6):2283-7.
• We studied the systemic arterial blood supply to the trachea and lung in adult sheep. After anesthesia, sheep were exsanguinated and then studied by intra-arterial injection of one of the following materials: saline containing dyes of various colors (n = 24), Microfil (n = 8), or Batson's solution (
• PMID 3610924

Related Links

• Right main bronchus - Wikipedia, the free encyclopedia

Latin, bronchus principalis dexter. Gray's · subject #237 1085. The right main bronchus (or right primary bronchus, or right principal bronchus) is a bronchus of the respiratory system. It is wider, shorter, and more vertical in direction than the left.

Related Pictures

---

★リンクテーブル★

リンク元	「右主気管支」
関連記事	「principal」

「右主気管支」

　　[★]

英

right main bronchus

ラ

bronchus principalis dexter

関

主気管支、気管支、右気管支

• 右の一次気管支。右の気管支を総称する場合に右気管支を使うものと思われる

臨床関連

• 一側肺換気：右主気管支は短く太い。このため、右用のチューブを用いる。詳しくは　→　一側肺換気#参考

「principal」

　　[★]

• adj.

• 主要な

• n.

• 校長

関

cardinal、chief、foremost、main、mainly、major、master、primarily、primary、principally