Introduction:
The important
basic function of larynx is to provide sphincteric protection to the
lower airway. This is achieved by adduction of vocal folds in
response to stimulation from the internal division of superior
laryngeal nerves. This mechanism is initiated by complex brain stem
response which is polysynaptic in nature. This reflex is sensitive
to variations in body core temperature. In febrile neonates, a
hypersensitive glottal closure reflex have been known to cause sudden
infant death syndrome.
Role of animal
studies in verifying this hypothesis:
Haraguchi etal
in their canine experiments demonstrated that hyperthemia enhances
the glottal closure reflex by decreasing the latency of nerve
stumulation thereby aumenting their conduction. In hypothermic
conditions they also demonstrated depression of glottal closure
reflex. The following are the inferences of this study:
- When the core body temperature raises axonal body temperature also raises.
- Conduction of sodium and potassium ions increase nearly 3 times with every 10 ° C increase in body temperature.
- Temperature drop caused delay in the release of neurotransmitters at the neuronal junctions.
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