A Study on Physical Factors Stimulating the Semicircular Canals Receptors (Cupola)

SUMMARY Although sciences and techniques have been significantly developed, many patients are still suffering from diagnostic and therapeutic problems of vestibular system, specially vertigo. Perhaps, these problems are not solved yet mostly because the neurophysiology of vestibular system and the stimulation mechanisms of the receptors are not known. This difficulty, intum, causes some a mbiguities and contrasts in the teaching of this CNS portion. Different physical factors such as: movement with angular acceleration (1-9), caloric variations (16-21) and sound waves (22-27) interfere in the stimulation of this receptors. To understand the mechanism of stimulation caused by rotation, endolymphatic flow hypothesis and two others called cupula inertia and pressuredifferences produced in both sides of cupula during rotation, are investigated in this research. The method of this research is based on the experimental method and the hypothesis are distinguished according to the variation of the axes of rotation. Therefore,the axes of rotation are selected in the front, back, right and left sides of The Cupula and the impulses transmitted through frogs'vestibular nerve are recorded in all of these four positions. According to the results,the most acceptable hypothesis is the one that indicates the flow of endolymph inside the semicircular canal during the rotation with angular acceleration. the reason for semicircular shape of these canals become more obvious too.