j reflex

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j reflex

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mjbapana
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01/19/08 - 05:48 PM

any one plz explain.thanx.

Tiff
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01/20/08 - 12:25 PM

Didn't know much about it, but found this article. Great read.

http://jp.physoc.org/cgi/content/full/511/1/2

new_n_lost
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01/20/08 - 12:36 PM

In other words Ganong explained it the best on pg 678 22th Ed.

" Receptors in the airways and lungs are innervated by myelinated and unmyelinated vagal fibers. The unmyelinated fibers are C fibers. The receptors innervated by myelinated fibers are commonly divided into slowly adapting receptors and rapidly adapting receptors on the basis of whether sustained stimulation leads to prolonged or transient discharge in their afferent nerve fibers (Table 36-2). The other group of receptors presumably consists of the endings of C fibers, and they are divided into pulmonary and bronchial subgroups on the basis of their location.

The shortening of inspiration produced by vagal afferent activity (Figure 36-3) is mediated by slowly adapting receptors. So are the Hering-Breuer reflexes. The Hering-Breuer inflation reflex is an increase in the duration of expiration produced by steady lung inflation, and the Hering-Breuer deflation reflex is a decrease in the duration of expiration produced by marked deflation of the lung. Because the rapidly adapting receptors are stimulated by chemicals such as histamine, they have been called irritant receptors. Activation of rapidly adapting receptors in the trachea causes coughing, bronchoconstriction, and mucus secretion, and activation of rapidly adapting receptors in the lung may produce hyperpnea.

Because the C fiber endings are close to pulmonary vessels, they have been called J (juxtacapillary) receptors. They are stimulated by hyperinflation of the lung, but they respond as well to intravenous or intracardiac administration of chemicals such as capsaicin. The reflex response that is produced is apnea followed by rapid breathing, bradycardia, and hypotension (pulmonary chemoreflex). A similar response is produced by receptors in the heart (Bezold-Jarisch reflex or the coronary chemoreflex; see Chapter 31). The physiologic role of this reflex is uncertain, but it probably occurs in pathologic states such as pulmonary congestion or embolization, in which it is produced by endogenously released substances.

Edited by new_n_lost on 04/10/08 - 01:05 AM. Reason: Corrected the Edition Number,

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mjbapana
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01/20/08 - 07:35 PM

thanx Tiff & new_n_lost.

macintosh
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04/09/08 - 09:09 PM

new_n_lost wrote:
In other words Ganong explained it the best on pg 678 27th Ed.

Are you sure it is the 27th edition. The most latest edition I can find is edition 22 here

new_n_lost
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04/10/08 - 01:06 AM

macintosh wrote:

Are you sure it is the 27th edition. The most latest edition I can find is edition 22 here

Sorry mate wrote the wrong edition. Corrected it and REally thanks for pointing it out.

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WolfgangWhite
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04/14/08 - 07:29 AM

Additionally,
You can find this information summarized on pg. 141 of Costanzo's BRS Physiology.

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