嘔吐反射

WordNet

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

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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）』「2012/07/26 21:25:16」(JST)

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The pharyngeal reflex or gag reflex is a reflex contraction of the back of the throat,^[1] evoked by touching the soft palate and occasionally the back of the tongue. It prevents something from entering the throat except as part of normal swallowing and helps prevent choking.

Reflex arc

In a reflex arc, a series of physiological steps occur very rapidly to produce a reflex. Generally a sensory receptor receives an environmental stimulus, in this case from objects reaching nerves in the back of your throat, and sends a message via an afferent nerve to the central nervous system (CNS). The CNS receives this message and sends an appropriate response via an efferent nerve (also known as a motor neuron) to effector cells located in the same initial area that can then carry out the appropriate response.^[2]

The afferent limb of this reflex is supplied by the glossopharyngeal nerve (cranial nerve IX), which synapses on the nucleus solitarius and the spinal trigeminal nucleus, both nuclei in the medulla oblongata in the brain stem. The efferent limb is supplied by the vagus nerve (cranial nerve X) from the nucleus ambiguus, also located in the medulla in the brain stem.

Suppression and activation

Swallowing unusually large objects or placing objects in the back of the mouth may cause the pharyngeal reflex. Some people, for instance sword swallowers, have learned how to suppress it.^[2] In contrast, triggering the reflex is sometimes done intentionally to induce vomiting, for example by those who suffer from bulimia nervosa.

Its absence

Absence of the gag reflex and pharyngeal sensation can be a symptom of a number of severe medical conditions, such as damage to the glossopharyngeal nerve, the vagus nerve, or brain death. However, in one study, one-third of healthy people did not have a gag reflex, although pharyngeal sensation in these subjects remained intact.^[3]

Reflexive Pharyngeal Swallow

Closely related to the gag reflex, in which food or other foreign substances are forced back out of the pharynx, swallowing generally pushes food through the digestive system into the stomach. However, this reflex in particular functions as a protective system for the upper respiratory tract.

Since both the digestive system and the respiratory system are connected by the pharynx, there are many problems and diseases that occur when the body is unable to regulate passage of food and air into the appropriate tracts. Therefore, reflexes such as this allow the pharynx to remove particles into the digestive tract that may have been forced back up by both this tract and the upper respiratory tract.

References

^ "Medical Neurosciences". http://www.neuroanatomy.wisc.edu/virtualbrain/BrainStem/09NA.html.
^ ^a ^b Wilson, Tracy V. (29 June 2007). "How Sword Swallowing Works". HowStuffWorks. http://entertainment.howstuffworks.com/arts/circus-arts/sword-swallowing.htm.
^ Davies, A. E.; Kidd, D.; Stone, S. P.; MacMahon, J. (February 1995). "Pharyngeal sensation and gag reflex in healthy subjects". Lancet 345 (8948): 487–488. PMID 7861875.

External links

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1. 悪心および嘔吐を伴う成人に対するアプローチ approach to the adult with nausea and vomiting
2. 周期性嘔吐症候群 cyclic vomiting syndrome
3. 悪心および嘔吐を呈する幼児または小児に対するアプローチ approach to the infant or child with nausea and vomiting
4. 化学療法誘発性悪心および嘔吐の病態生理および予測 pathophysiology and prediction of chemotherapy induced nausea and vomiting
5. 成人における神経性大食症：認知行動療法（CBT） bulimia nervosa in adults cognitive behavioral therapy cbt

English Journal

Evaluation and Treatment of Chronic Cough.

Terasaki G1, Paauw DS2.Author information 1Division of General Internal Medicine, Harborview Medical Center, University of Washington, Box 359780, 325 Ninth Avenue, Seattle, WA 98104, USA. Electronic address: terasaki@u.washington.edu.2Division of General Internal Medicine, University of Washington, Box 356420, BB527 Health Sciences Building, Seattle, WA 98195, USA.AbstractChronic cough is a common and frustrating problem for patients and health care providers that can result in a range of physical and psychological complications including exhaustion, urinary incontinence, vomiting, depression, and social isolation. A step-wise empiric approach to treatment will increase the likelihood of a successful resolution of the cough. Even with current treatment protocols, a subset of patients will continue to have chronic cough without a diagnosis. As understanding of the pathophysiology of chronic cough evolves particularly around the concept of cough reflex hypersensitivity, future research should lead to new diagnostic and therapeutic modalities for this challenging problem.
The Medical clinics of North America.Med Clin North Am.2014 May;98(3):391-403. doi: 10.1016/j.mcna.2014.01.002. Epub 2014 Mar 15.
Chronic cough is a common and frustrating problem for patients and health care providers that can result in a range of physical and psychological complications including exhaustion, urinary incontinence, vomiting, depression, and social isolation. A step-wise empiric approach to treatment will incre
PMID 24758953

The oculocardiac reflex during strabismus surgery: its relationship to preoperative clinical eye findings and subsequent postoperative emesis.

Lai YH1, Hsu HT2, Wang HZ3, Cheng KI4, Wu KY3.Author information 1Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.2School of Nursing, College of Nursing, Kaohsiung Medical University, Kaohsiung, Taiwan.3Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Ophthalmology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.4Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan. Electronic address: yuhula@kmu.edu.tw.AbstractPURPOSE: To compare the occurrence of significant bradycardia due to the oculocardiac reflex (OCR) during strabismus surgery and its relationship to preoperative clinical eye findings and subsequent development of postoperative emesis.
Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus / American Association for Pediatric Ophthalmology and Strabismus.J AAPOS.2014 Apr;18(2):151-5. doi: 10.1016/j.jaapos.2013.11.024.
PURPOSE: To compare the occurrence of significant bradycardia due to the oculocardiac reflex (OCR) during strabismus surgery and its relationship to preoperative clinical eye findings and subsequent development of postoperative emesis.METHODS: The medical records of consecutive patients who underwen
PMID 24698612

Gravity-dependent Nystagmus and Inner-Ear Dysfunction Suggest Anterior and Posterior Inferior Cerebellar Artery Infarct.

Shaikh AG1, Miller BR2, Sundararajan S2, Katirji B2.Author information 1Department of Neurology, Case Western Reserve University, Cleveland, Ohio. Electronic address: aasefshaikh@gmail.com.2Department of Neurology, Case Western Reserve University, Cleveland, Ohio.AbstractCerebellar lesions may present with gravity-dependent nystagmus, where the direction and velocity of the drifts change with alterations in head position. Two patients had acute onset of hearing loss, vertigo, oscillopsia, nausea, and vomiting. Examination revealed gravity-dependent nystagmus, unilateral hypoactive vestibulo-ocular reflex (VOR), and hearing loss ipsilateral to the VOR hypofunction. Traditionally, the hypoactive VOR and hearing loss suggest inner-ear dysfunction. Vertigo, nausea, vomiting, and nystagmus may suggest peripheral or central vestibulopathy. The gravity-dependent modulation of nystagmus, however, localizes to the posterior cerebellar vermis. Magnetic resonance imaging in our patients revealed acute cerebellar infarct affecting posterior cerebellar vermis, in the vascular distribution of the posterior inferior cerebellar artery (PICA). This lesion explains the gravity-dependent nystagmus, nausea, and vomiting. Acute onset of unilateral hearing loss and VOR hypofunction could be the manifestation of inner-ear ischemic injury secondary to the anterior inferior cerebellar artery (AICA) compromise. In cases of combined AICA and PICA infarction, the symptoms of peripheral vestibulopathy might masquerade the central vestibular syndrome and harbor a cerebellar stroke. However, the gravity-dependent nystagmus allows prompt identification of acute cerebellar infarct.
Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association.J Stroke Cerebrovasc Dis.2014 Apr;23(4):788-90. doi: 10.1016/j.jstrokecerebrovasdis.2013.05.020. Epub 2013 Jun 22.
Cerebellar lesions may present with gravity-dependent nystagmus, where the direction and velocity of the drifts change with alterations in head position. Two patients had acute onset of hearing loss, vertigo, oscillopsia, nausea, and vomiting. Examination revealed gravity-dependent nystagmus, unilat
PMID 23800506

Japanese Journal

Osseous Choristoma in Child with Strong Vomiting Reflex

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The Bulletin of Tokyo Dental College 55(4), 207-215, 2014
… Here, we report an osseous choristoma on the posterior portion of the tongue in a patient with a strong vomiting reflex. …
NAID 130004713441

特発性食道粘膜下血腫が原因と考えられた食道粘膜剥離症の1例

楠原光謹,土岐真朗,落合一成,太田博崇,神保陽子,大野亜希子,倉田勇,田部井弘一,畑英行,蓮江智彦,平野和彦,林田真理,徳永健吾,山口康晴,大倉康男,高橋信一
Progress of Digestive Endoscopy 83(1), 96-97, 2013
… After extubation, the patient developed vomiting and severe precordial chest pain. … Judging by the clinical course, the cause of the symptoms was considered to be spontaneous intramural hematoma of the esophagus associated with the vomiting reflex after extubation. …
NAID 130004652926

第5回若手奨励賞受賞論文術後の嘔気・嘔吐--選択的ニューロキニン1受容体拮抗薬が及ぼす影響

門田尚子,堤保夫,大下修造 [他]
四国医学雑誌 67(3・4), 143-146, 2011-08-25
… Post-operative nausea and vomiting（PONV）remains the most frequently reported patientscomplaint after anesthesia, and for patients, it is of greater concern than postoperative pain. …
NAID 40018975219