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The fine morphology of the sensory receptor organs in the auricle of the rat
Author(s) -
Cauikolajs
Publication year - 1969
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.901360106
Subject(s) - free nerve ending , anatomy , biology , axon , sensory receptor , auricle , sensory system , hair follicle , microbiology and biotechnology , neuroscience
The fine structure, distribution of cholinesterase activity and microtopography of the sensory receptor organs of the rat's auricle were studied in six animals. It was found that the skin of the auricle consisted of minute but well defined receptor territories each supplied by a morphologically distinct nerve ending. The horizontal endings, derived from non‐myelinated nerve fibers, supplied linear skin areas covering the intervals between the hair orifices and sending fine twigs into the epidermis. They had the simplest morphology and showed no cholinesterase activity. The papillary endings were restricted to the immediate vicinity of the hair orifices. They exhibited butyrocholinesterase activity and showed a typical fine morphology. The expanded axon terminals were filled with mitochondria and enclosed by Schwann cells of some complexity. The nerve endings of the fine hairs were derived from myelinated axons. The endings showed acetyl‐ and butyrocholinesterase activity. The terminal fibers ended in spindles that were arranged longitudinally in a semicircle around the epithelial root sheath of the hair forming a single layer between the orifices of the sebaceous glands and the base of the hair follicle. The endings were characterized by the accumulation of mitochondria and microvesicles in the terminal spindles and by the high pinocytotic activity in the associated Schwann cell processes. The deep tissues contained at least one kind of simple beaded nerve ending that gave a negative cholinesterase reaction. It was concluded that the morphological diversity of the sensory apparatus was adequate to account for a considerable degree of specificity or at least selectivity of its end organs.