Bezold-Jarisch reflex

The Bezold-Jarisch reflex involves a variety of cardiovascular and neurological processes which cause hypopnea and bradycardia.cite journal |author=Salo LM, Woods RL, Anderson CR, McAllen RM |title=Nonuniformity in the von Bezold-Jarisch reflex |journal=Am. J. Physiol. Regul. Integr. Comp. Physiol. |volume=293 |issue=2 |pages=R714–20 |year=2007 |month=August |pmid=17567718 |doi=10.1152/ajpregu.00099.2007 |url=http://ajpregu.physiology.org/cgi/pmidlookup?view=long&pmid=17567718]

Physiology

Prolonged upright posture results in some degree of pooling of blood in the lower extremities that can lead to diminished intracardiac volume.

This phenomenon is accentuated if the individual is dehydrated.

The resultant arterial hypotension is sensed in the carotid body baroreceptors, and afferent fibers from these receptors trigger autonomic signals that increase cardiac rate and contractility.

However, pressure receptors in the wall and trabeculae of the underfilled left ventricle may then sense stimuli, indicating high-pressure C-fiber afferent nerves from these receptors.

They may respond by sending signals that trigger paradoxical bradycardia and decreased contractility, resulting in additional and relatively sudden arterial hypotension. [ [http://www.emedicine.com/ped/topic2188.htm eMedicine - Syncope : Article by M Silvana Horenstein, MD ] ]

History

It is named for Albert von Bezold and Adolf Jarisch Junior. [WhoNamedIt|synd|3165]

References