A contribution to the nomenclature of peripheral sensory structures (sensory nerve endings)

The author has shown the variety in denominating peripheral sensory structures serving for mechanoreception, nociception, thermoreception and chemoreception. To term peripheral sensory structures as nerve endings is considered particularly unsuitable because this denomination is based only on morphogenesis of the ending. From the view of system approach, the peripheral sensory structures forms one unit formed by two or more structural subsystems. Even though the axon or its dendritic zone has the leading role in this unit, the function of the whole formation is influenced (modulated) by further non-nervous components. Although the causes of velocity of adaptation in some sensory structures have been already explained (e.g. in lamellar corpuscles with a thick capsule), different adaptation velocity of Merkel complexes in reptiles and birds on one side, and in mammals on the other, with the same structure has not been clear up to now. From the view of system approach as well as of the share of non-nervous components in the activity of the whole sensory structure, the author has suggested to introduce the term "sensory nerve formation" for peripheral sensory structures serving for mechanoreception, nociception, thermoreception and chemoreception. The term "complex sensory nerve formation" is suggested for more complex sensory structures in which either more sensory nerve formations of the same kind (Pinkus tactile dics) or different kinds of sensory formations (Eimer organ of a mole) are connected constantly or in which the connection of sensory nerve formations with other supporting structures (hairs, feathers) occurs.     

Fiber size and sensory endings of the middle cardiac nerve of the domestic fowl (Gallus domesticus)

The middle cardiac nerve, a branch of the vagus, innervates the ventricles of the avian heart. Of 533 myelinated sensory fibers, the size range was 2 micron. The ratio of myelinated to unmyelinated sensory fibers ranged from 2.17 to 3.48. Sensory endings resembled a network pattern with no distinct receptor-like endings. Frequency of nerve population increased from apex to base of the heart.     

Sarcoma arising from interdigitating cells. Cytology and cytochemistry

The cytologic features of a highly malignant sarcomatous tumor in a 37-year-old male, arising from interdigitating cells and localized in the mediastinum, lymph nodes and skin, are described. Cytologically this sarcoma was characterized by large cells with ill-defined, faintly basophilic cytoplasm, monocytoid or multilobulated nuclei and a reticular chromatin structure; very prominent nucleoli were seen in some of the cells. Some of the tumor cells were spindle shaped. The ultrastructurally characteristic invaginations of the cell membrane were not obvious in the cytologic smear, although the nuclear membrane showed deep, narrow, channel-like indentations. The specific ultrastructural, immunologic and cytochemical characteristics of the interdigitating cells were recognized in the tumor cells. Adenosine triphosphatase was present in the tumor cells in large amounts, while acid phosphatase, acid alpha-naphthyl acetate esterase and other enzymes were absent. The described tumor must be considered another tumor of the mononuclear phagocyte system; the proposed name is "interdigitating-cell sarcoma."     

Autotomy of sensory nerve endings in the area of microvessels]

The phenomenon of autotomy of peripheral receptor terminals, in the area of the intestinal microvessel bed has been analysed. This phenomenon is accompanied with a real separation of the terminal patches or large fragments of receptors with their successive degeneration. The effect of the terminals autotomy is succeeded in reproducing and analysing in dynamics in tissue culture. The computer analysis of the image demonstrates that autotomy is observed not only in developing structures during early period of ontogenesis, but in well developed, as regards all morphological criteria, tissue receptors of mature animals. The investigations have been performed by means of silver nitrate impregnation after Bielschowsky--Gros, as well as using vital microscopy. An idea has been formed that autotomy is a part of the cyclic process of autotomy--regeneration of the terminals. This process is connected with retractile cytopoiesis, apocrine secretion. A high concentration of proteolytic enzymes in the amputated degrading fragment of the receptor can serve as a trophic factor, activating the local metabolic process in the area of microvessels.     

Quantitative evaluation of sensory nerve endings in hypertrophy of labia minora pudendi in women.

The authors studied the types of sensory nerve endings in hypertrophic labia minora pudendi in women aged between 18 and 69. The nervous tissue was impregnated with silver nitrate by Lavrentyev's modification of the Bielschowski-Gross method. The sensory nerve endings were divided into the following groups: free endings and arborizations, spray-like endings, seven types of clew-like nerve endings, and Pacinian corpuscles. It is the clew-like endings that absolutely predominate, they were 2,027 in number. The arborizations and spray-like endings found were 105 in number and only 4 of Pacinian corpuscles were found. As compared with normal labia there are no principal differences among the types of sensory nerve endings. The main difference consists in the rate of occurrence (89.6 as against 57.8) and in the thickness of the capsule, while the nerve clew proper does not grow in diameter. Therefore, we are of theopinion that a more frequent occurrence and larger size of the capsule is associated with local changes in the organ (especially with hypertrophy of the connective tissue). We observed no differences due to age either in the occurrence of the individual types or in the thickness of the capsule. Great individual variability in both directions was seen. The findings corroborated again the rare occurrence of meissner's endings in the labia minora in woman. Therefore it may be assumed that it is rather a random finding and that it is a type of clew-like nerve ending. Finally, we presume that the individually varying rate of occurrence of the nerve endings in the external genitals could also affect general sensitivity in this region, including sexual sensitivity.