Bronchus
Bronchus | |
---|---|
Bronchial vein | |
Nerve | Pulmonary branches of vagus nerve |
Identifiers | |
Latin | bronchus |
MeSH | D001980 |
TA98 | A06.4.01.001 A06.3.01.008 |
TA2 | 3226 |
FMA | 7409 |
Anatomical terminology] |
A bronchus (
Structure
The
The right main bronchus is wider, shorter, and more vertical than the left main bronchus,
The left main bronchus is smaller in caliber but longer than the right, being 5 cm long. It enters the
The secondary bronchi divide further into tertiary bronchi, (also known as segmental bronchi), each of which supplies a
The main bronchi have relatively large
The bronchial wall normally has a thickness of 10% to 20% of the total bronchial diameter.[6]
Microanatomy
The
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 ciliated cuboidal epithelium, to simple
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.[9] 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.[10] [11]
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.[12]
An accessory cardiac bronchus is usually an asymptomatic condition but may be associated with persistent infection or
Function
The bronchi function to carry
Clinical significance
Bronchial wall thickening, as can be seen on CT scan, generally (but not always) implies inflammation of the bronchi (bronchitis).[15] Normally, the ratio of the bronchial wall thickness and the bronchial diameter is between 0.17 and 0.23.[16]
Bronchitis
Bronchitis is defined as inflammation of the bronchi, which can either be
Aspiration
The left main bronchus departs from the trachea at a greater angle than that of the right main bronchus. The right bronchus is also wider than the left and these differences predispose the right lung to aspirational problems. If food, liquids, or foreign bodies are aspirated, they will tend to lodge in the right main bronchus. Bacterial pneumonia and aspiration pneumonia may result.
If a tracheal tube used for intubation is inserted too far, it will usually lodge in the right bronchus, allowing ventilation only of the right lung.
Asthma
Asthma is marked by hyperresponsiveness of the bronchi with an inflammatory component, often in response to allergens.
In asthma, the constriction of the bronchi can result in difficulty in breathing giving
Bronchial atresia
Bronchial atresia is a rare congenital disorder that can have a varied appearance. A bronchial atresia is a defect in the development of the bronchi, affecting one or more bronchi – usually segmental bronchi and sometimes lobar. The defect takes the form of a blind-ended bronchus. The surrounding
The collected mucus may form a mucoid impaction or a bronchocele, or both. A pectus excavatum may accompany a bronchial atresia.[17]
Additional images
-
Cross-section of secondary bronchus
-
The left and right main bronchi sit behind the heart, shown here.
Citations
- ISBN 978-1-4557-0418-7.
- ISBN 0-13-981176-1.[page needed]
- PMID 2642720.
- ISBN 9780073378251.
- ISBN 9781469824796.
- ^ a b
Marieb, Elaine N.; Hoehn, Katja (2012). Human Anatomy & Physiology (9th ed.). Pearson. ISBN 978-0321852120.
- ^ "Bronchi, Bronchial Tree & Lungs". nih.gov. Retrieved 18 September 2019.
- ^ Weerakkody, Yuranga. "Tracheal bronchus | Radiology Reference Article | Radiopaedia.org". Radiopaedia. Retrieved 21 November 2021.
- PMID 19332762.
- ^
Barat, Michael; Horst R. Konrad (1987-03-04). "Tracheal bronchus". American Journal of Otolaryngology. 8 (2): 118–122. PMID 3592078.
- ^ "Cardiac bronchus". Radiopedia. Archived from the original on 2015-11-15.
- ISBN 3131390212
- PMID 8210391.
- ^ Weerakkody, Yuranga (2021-01-13). "Bronchial wall thickening". Radiopaedia. Retrieved 2018-01-05.
- ISBN 9780781757683.
- ^ PMID 29302450.
- PMID 1494776.
Sources
- Moore, Keith L. and Arthur F. Dalley. Clinically Oriented Anatomy, 4th ed. (1999). ISBN 0-7817-5936-6.