WordNet

a sudden noisy expulsion of air from the lungs that clears the air passages; a common symptom of upper respiratory infection or bronchitis or pneumonia or tuberculosis (同)coughing
exhale abruptly, as when one has a chest cold or congestion; "The smoker coughs all day"
an automatic instinctive unlearned reaction to a stimulus (同)reflex response, reflex action, instinctive reflex, innate reflex, inborn reflex, unconditioned_reflex, physiological reaction
(of leaves) bent downward and outward more than 90 degrees

PrepTutorEJDIC

〈C〉『せき』,せき払 / 《a ~》よくせきの出る病気 / 『せきをする』,せき払いする / せきのような音を出す / …'を'せきをして吐き出す《+『up』(『out』)+『名,』+『名』+『up』(『out』)》
反射(刺激に対する無意識の反応) / 《複数形で》反射的な動き / (光などの)反射,反射光;映像 / 反射性の / (カメラが)レフ鋼の,反射型の

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/02/10 21:08:36」(JST)

wiki en

The cough reflex has both sensory (afferent) mainly via the vagus nerve and motor (efferent) components. Pulmonary irritant receptors (cough receptors) in the epithelium of the respiratory tract are sensitive to both mechanical and chemical stimuli. The bronchi and trachea are so sensitive to light touch that slight amounts of foreign matter or other causes of irritation initiate the cough reflex.^[1] The larynx and carina are especially sensitive, and the terminal bronchioles and even the alveoli are sensitive to chemical stimuli such as sulfur dioxide gas or chlorine gas.^[1] The rapidly moving air usually carries with it any foreign matter that is present in the bronchi or trachea.^[1] Stimulation of the cough receptors by dust or other foreign particles produces a cough, which is necessary to remove the foreign material from the respiratory tract before it reaches the lungs.

Physiology

The cough receptors, or rapidly adapting irritant receptors are located mainly on the posterior wall of the trachea, pharynx, and at the carina of trachea, the point where the trachea branches into the main bronchi. The receptors are less abundant in the distal airways, and absent beyond the respiratory bronchioles. When triggered, impulses travel via the internal laryngeal nerve, a branch of the superior laryngeal nerve which stems from the vagus nerve (CN X), to the medulla of the brain. This is the afferent neural pathway. Unlike other areas responsible for involuntary actions like swallowing, there is no clearly identifiable area that can be labeled as the cough center in the brain.

The efferent neural pathway then follows, with relevant signals transmitted back from the cerebral cortex and medulla via the vagus and superior laryngeal nerves to the glottis, external intercostals, diaphragm, and other major inspiratory and expiratory muscles. The mechanism of a cough is as follows:

Diaphragm (innervated by phrenic nerve) and external intercostal muscles (innervated by segmental intercostal nerves) contract, creating a negative pressure around the lung.
Air rushes into the lungs in order to equalise the pressure.
The glottis closes (muscles innervated by recurrent laryngeal nerve) and the vocal cords contract to shut the larynx.
The abdominal muscles contract to accentuate the action of the relaxing diaphragm; simultaneously, the other expiratory muscles contract. These actions increase the pressure of air within the lungs.
The vocal cords relax and the glottis opens, releasing air at over 100 mph.
The bronchi and non-cartilaginous portions of the trachea collapse to form slits through which the air is forced, which clears out any irritants attached to the respiratory lining.

Stimulation of the auricular branch of the vagus nerve supplying the ear may also elicit a cough. This is known as Arnold's reflex. Respiratory muscle weakness, tracheostomy, or vocal cord pathology (including paralysis or anesthesia) may prevent effective clearing of the airways.

Dysfunction

The reflex is impaired in the person whose abdominals and respiratory muscles are weak. This problem can be caused by disease condition that lead to muscle weakness or paralysis, by prolonged inactivity, or as outcome of surgery involving these muscles.^{[citation needed]} Bed rest interferes with the expansion of the chest and limits the amount of air that can be taken into the lungs in preparation for coughing, making the cough weak and ineffective.^{[citation needed]} This reflex may also be impaired by damage to the internal branch of the superior laryngeal nerve which relays the afferent branch of the reflex arc.^{[citation needed]} This nerve is most commonly damaged by swallowing a foreign object, such as a chicken bone, resulting in it being lodged in the piriform recess (in the laryngopharynx) or by surgical removal of said object.

Testing

The cough reflex can be tested by inhaling air with nebulized 200µmol/l capsaicin.^[2]

References

^ ^a ^b ^c Hall, John (2011). Guyton and Hall Textbook of Medical Physiology with Student Consult Online Access (12th ed.). Philadelphia: Elsevier Saunders. ISBN 978-1-4160-4574-8.
^ Hegland, K. W.; Bolser, D. C.; Davenport, P. W. (2012). "Volitional control of reflex cough". Journal of Applied Physiology 113: 39. doi:10.1152/japplphysiol.01299.2011.

UpToDate Contents

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1. 成人における亜急性および慢性咳嗽の評価 evaluation of subacute and chronic cough in adults
2. 気道の神経制御 neuronal control of the airways
3. 成人における嚥下性肺炎 aspiration pneumonia in adults
4. 緩和ケア：咳嗽、上気道性喘鳴、および喀血の概要 palliative care overview of cough stridor and hemoptysis
5. 肺移植後の生理的変化 physiologic changes following lung transplantation

English Journal

Inhibitory effect of cervical trachea and chest wall vibrations on cough reflex sensitivity and perception of urge-to-cough in healthy male never-smokers.

Kashiwazaki N, Ebihara S, Gui P, Katayama N, Ito K, Sato R, Oyama C, Ebihara T, Kohzuki M.AbstractBACKGROUND: Non-pharmacological options for symptomatic management of cough are desired. Although chest wall mechanical vibration is known to ameliorate cough reflex sensitivity, the effect of mechanical vibrations on perceptions of urge-to-cough has not been studied. Therefore, we investigated the effect of mechanical vibration of cervical trachea, chest wall and femoral muscle on cough reflex sensitivity, perceptions of urge-to-cough as well as dyspnea.
Cough (London, England).Cough.2013 Oct 2;9(1):22. [Epub ahead of print]
BACKGROUND: Non-pharmacological options for symptomatic management of cough are desired. Although chest wall mechanical vibration is known to ameliorate cough reflex sensitivity, the effect of mechanical vibrations on perceptions of urge-to-cough has not been studied. Therefore, we investigated the
PMID 24088411

Pharmacodynamic modeling of cough responses to capsaicin inhalation calls into question the utility of the C5 end point.

Hilton EC, Baverel PG, Woodcock A, Van Der Graaf PH, Smith JA.SourceRespiratory Research Group, University of Manchester, Manchester, United Kingdom.
The Journal of allergy and clinical immunology.J Allergy Clin Immunol.2013 Oct;132(4):847-855.e5. doi: 10.1016/j.jaci.2013.04.042. Epub 2013 Jun 15.
BACKGROUND: Inhaled capsaicin elicits cough reproducibly in human subjects and is widely used in the study of cough and antitussive therapies. However, the traditional end points C2 and C5 (the concentrations of capsaicin inducing at least 2 or 5 coughs, respectively) display extensive overlap betwe
PMID 23777849

Chronic Cough: An Update.

Iyer VN, Lim KG.SourceDivision of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN.
Mayo Clinic proceedings. Mayo Clinic.Mayo Clin Proc.2013 Oct;88(10):1115-1126. doi: 10.1016/j.mayocp.2013.08.007.
Cough persisting beyond 8 weeks (ie, chronic cough) is one of the most common reasons for an outpatient visit. A protracted cough can negatively affect one's quality of life by causing anxiety, physical discomfort, social isolation, and personal embarrassment. Herein, the anatomy and physiology of t
PMID 24079681

Japanese Journal

咳嗽と喀痰のメカニズム (特集咳嗽の実地診療Up-to-date)

呼吸器内科 = Respiratory medicine 29(2), 87-92, 2016-02
NAID 40020796562

気管切開術後に生じた全身皮下気腫・縦隔気腫例

耳鼻咽喉科臨床 109(6), 433-437, 2016
NAID 130005154477

誤嚥による咳嗽 (特集咳嗽診療のすべて)

日本胸部臨床 74(11), 1217-1226, 2015-11
NAID 40020643449

Related Pictures

★リンクテーブル★

リンク元	「脳幹反射」「咳嗽反射」
関連記事	「reflex」

「脳幹反射」

　　[★]

英: brain stem reflex
関: 脳死判定基準

咳反射	cough reflex	せき
角膜反射	corneal reflex	かくまく
毛様体脊髄反射	ciliospinal reflex	もうようたいせきずい
眼球頭反射	oculocephalic reflex	がんきゅうとう
咽頭反射	pharyngeal reflex	いんとう
前庭反射	vestibular reflex	ぜんてい
対光反射	light reflex	たいこう