词条 | Obligate nasal breathing |
释义 |
HumansHuman infants are commonly described as obligate nasal breathers as they prefer breathing through their nose rather than mouth.[3] Most infants, however, are able to breathe through their mouth if their nose is blocked.[3] There are however certain infants with conditions such as choanal atresia in which deaths have resulted from nasal obstruction.[3] In these cases there are cyclical periods of cyanosis. The infant initially attempts to breathe through the nose, and is unable to; hypercapnia occurs, and many babies instinctively begin to cry. While crying, oral ventilation occurs and cyanosis subsides. There is variation in the length of time until a baby begins oral breathing, and some will never cease attempts at nasal breathing. It has also been suggested that infants may not be able to sustain oral breathing for significant lengths of time, because of the weakness of the muscles required to seal the nasal airway and open the oral airway.[3] Other animalsHorses are also considered obligate nasal breathers. The term is more accurate in horses, because their normal anatomy prevents them from breathing orally. The epiglottis rests above the soft palate while the animal is not swallowing, forming an airtight seal. Oral breathing can only occur with significant anatomical abnormalities or pathological conditions. For example, denervation of the pharyngeal branch of the vagus nerve results in dorsal displacement of the soft palate (DDSP),[4] and it has been suggested that this leads to a clinical syndrome which may include oral breathing.[5] However, significant respiratory dysfunction including airway obstruction is observed with DDSP, and the animal cannot function normally in this state. Rabbits and rodents are also obligate nasal breathers. Like horses, the normal anatomical position of the epiglottis causes it to be engaged over the caudal rim of the soft palate, sealing the oral pharynx from the lower airways.[6] Even so, rabbits with advanced upper airway disease will attempt to breathe through their mouths. Many other mammals, such as cats, dogs, and adult humans, have the ability to breathe indefinitely through either the oral or nasal cavity.[7] References1. ^SIDS and Otitis media – an anatomical perspective, Presented by: Brian Palmer, D.D.S., December 2001. 2. ^{{cite journal |last1=Negus |first1=VE |title=The Function of the Epiglottis. |journal=Journal of Anatomy |volume=62 |issue=Pt 1 |pages=1–8 |year=1927 |pmid=17104162 |pmc=1250045}} 3. ^1 2 3 {{cite journal |last1=Bergeson |first1=P. S. |last2=Shaw |first2=J. C. |title=Are Infants Really Obligatory Nasal Breathers? |journal=Clinical Pediatrics |volume=40 |issue=10 |pages=567–9 |year=2001 |pmid=11681824 |doi=10.1177/000992280104001006}} 4. ^{{cite journal |last1=Holcombe |first1=SJ |last2=Derksen |first2=FJ |last3=Stick |first3=JA |last4=Robinson |first4=NE |title=Effect of bilateral blockade of the pharyngeal branch of the vagus nerve on soft palate function in horses. |journal=American journal of veterinary research |volume=59 |issue=4 |pages=504–8 |year=1998 |pmid=9563638}} 5. ^{{cite journal|url=http://www.ivis.org/proceedings/aaep/1998/Holcombe.pdf|title=Neuromuscular Regulation of the Larynx and Nasopharynx in the Horse|author=Susan J. Holcombe|journal=Proceedings of the Annual Convention of the AAEP |year=1998|page=26|volume=44}} 6. ^{{cite journal|url=http://www.aemv.org/Documents/AAV07smallbookfinal.pdf#page=69|title=The Rabbit Respiratory System: Anatomy, Physiology, and Pathology|author=Stephen J. Hernandez-Divers|journal=Proceedings of the Association of Exotic Mammal Veterinarians|year=2007|pages=61–68}} 7. ^{{cite book |editor1-first=Otto M. |editor1-last=Radostits |editor2-first=I. G. Joe |editor2-last=Mayhew |editor3-first=Doreen M. |editor3-last=Houston |title=Veterinary clinical examination and diagnosis |publisher=W. B. Saunders |location=Philadelphia |year=2000 |page= |isbn=0-7020-2476-7}}{{page needed|date=January 2011}} External links
1 : Respiration |
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