Sensory Organs: Organs of Hearing, Equilibrium, and Taste
8 topics with a brief review: definitions, key facts, and classroom questions.
In this section, we analyze the microscopic structure of the peripheral parts of analyzers responsible for the perception of sound, body position in space, and the chemical composition of food (taste).
The material covers the general characteristics of the sensory organs and details the histology of the auditory and vestibular systems: from the outer and middle ear to the complex bony and membranous labyrinth of the inner ear. Special attention is paid to the cochlea, the spiral organ (organ of Corti), the receptor zones of the vestibular apparatus, as well as the structure of the gustatory organ.
During practical classes and exams, instructors most frequently ask about the cellular composition of the organ of Corti, the mechanism of transformation of mechanical vibrations into a nerve impulse, and the histophysiology of the hair cells of the maculae and ampullary crests. A firm knowledge of these structures is an absolute minimum for understanding the pathogenesis of sensorineural hearing loss and vestibular disorders.
What acts as the receptor in secondary sense organs?
In these organs, reception is performed not by neurons, but by specialized epithelial (epitheliosensory) cells.
What type of cartilage tissue forms the basis of the auricle?
The basis of the auricle is formed by elastic cartilage, which provides its flexibility and resilience.
With which anatomical structure does the Eustachian tube connect the tympanic cavity?
The auditory tube connects the tympanic cavity with the nasopharynx. This is necessary for air entry and pressure equalization.
Where exactly is the spiral organ located?
The spiral (cochlear) organ is located strictly within the membranous labyrinth, specifically inside the membranous cochlea (cochlear duct).
What is the histological uniqueness of the stria vascularis of the lateral wall?
The stria vascularis is formed by a stratified epithelium containing blood capillaries. Normally, epithelial tissues lack their own blood vessels, but here they are necessary to supply the process of endolymph secretion.
How is the inner tunnel formed, and what is it filled with?
The inner tunnel is formed by the diverging bodies of the inner and outer pillar cells, whose apices are in tight contact with each other. The space inside the tunnel is filled with endolymph.
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