摘要:

AbstractIntramuscular nerve branches are covered by a complex of epithelial sheaths which decrease in thickness and complexity as the nerves branch to reach ultimate termination of neuromuscular junctions. The outermost layer (epineurium) of intramuscular nerves is composed of thin processes of fibrocytes lacking basement lamina and associated with parallel bundles of collagen. Internal to this layer are two or three layers of interdigitating perineural cells covered with basement lamina. The innermost layer is frequently incompletely covered by basement lamina within the perineural sheath. Schwann cells covered with basement lamina enclose myelinated and unmyelinated axons.In the region of neuromuscular junctions, the basement lamina of Schwann cell processes merge with the myofiber basement lamina. Thin perineural cell processes form a bell‐shaped covering which does not reach the muscle basement lamina. The relationships of myelin to the axon as the terminal axon emerges from the Schwann cell closely resembles the relationships of these structures in nodes of Ranvie

ISSN:0003-276X    

DOI:10.1002/ar.1091640401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractThe manner of insertion of intrafusal (IF) fibers of muscle spindles has been studied in serial histological sections of spindles from hindlimb muscle of the cat, opossum, mouse, rat, bat and gibbon. Four basic types of IF terminations in relation to the capsule were recognized: (A) direct insertion into the capsule; (B) strong lateral attachments to the capsule, though the fiber may continue beyond the capsule; (C) termination in the connective tissue beyond the limits of the capsule; (D) free extension of the fiber beyond the capsule. Bag fibers in all species generally extended beyond the capsule. The pattern of chain fiber insertion, however, varied with the species. Most rat spindles, for example, followed the D pattern, those in the cat pattern A, and the gibbon chiefly A and B. The bearing of these findings upon a postulated mechanism by which spindles may detect intramuscular pressures, as changes in length, is discussed.

ISSN:0003-276X    

DOI:10.1002/ar.1091640402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractComparative light and electron microscopic study of nuclei in rat trigeminal neurons identified two structures which are the ultrastructural equivalent of the paranucloelar structure and the accessory body of Cajal, two nucleoplasmic structures previously demonstrated in other neurons by light microscope silver staining methods. Ultrastructural evidence indicates that the dense component of the nucleolus is converted into the paranucleolar structure, which then detaches from the nucleolar surface to lie free in the nucleoplasm as the accessory body of Cajal. The cytochemistry, ultrastructure, and antimonate reactivity of the paranucleolar structure and accessory body were identical. Both structures lacked cytochemically demonstrable DNA, RNA, or basic protein.The neuronal nuclei also contained Feulgen‐positive sex chromatin bodies that adhered to the nucleolus, the nuclear membrane, or to both of these structures in specimens of female but not male rats. The ultrastructure and antimonate reactivity of these bodies closely resembled that of heterochromatin clumps but differed markedly from that of the paranucleolar structures and accessory bodies.Additional structures characterized ultrastructurally included patches, granular bodies, and flakes. These structures, like the paranucleolar structure and the accessory body of Cajal, are apparently unique to nuclei of neurons. Cytochemical methods showed that the patches contained basic protein but no nucleic aci

ISSN:0003-276X    

DOI:10.1002/ar.1091640403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractPhotophores inPorichthys notatusconsist of a cellular lens, an underlying area of photogenic tissue and a deep ensheathing reflector. Lens cells exhibit a dense compacted filamentous cytoplasm. Their processes interdigitate and desmosomes exist along their borders. The photogenic tissue, richly supplied by blood vessels, consists of two main cell types: (1) a presumed “photogenic” cell; and (2) a supportive cell. Photogenic cells are characterized by a highly vesiculated cytoplasm and peripheral microvilli. Frequently, they exhibit lamellar membranous whorls. Some whorls display cytoplasmic cores with vesicles. Many of these vesicles communicate via pores with an extracellular channel that envelops the cells. Supportive cells contain cytoplasmic filaments and extend processes around the photogenic cells. Except for isolated desmosomal contact points, a wide extracellular channel intervenes between supportive and photogenic cells. A prominent basal lamina separates supportive cells from the surrounding connective tissue. The strongly birefringent reflector is composed primarily of cells containing guanine crystals. The crystals lie stacked in groups, each membrane‐bounded crystal being separated from its neighbor by an intervening layer of cytoplasm. Such an arrangement produces constructive interference and accounts for the high reflectivity of this multilayered structure. Possible relationships of the above structural features and the production of light are disc

ISSN:0003-276X    

DOI:10.1002/ar.1091640404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractPhotophores inPorichthys notatusare bioluminescent organs composed of a lens, photogenic tissue, and an underlying reflector. Nerves penetrate through the reflector and branch, free of their Schwann cells, among the photogenic tissue elements. The tortuous pathways of axons have been followed by electron microscopical serial sections. After giving off occasional terminal branches, the axons continue into pockets of connective tissue which penetrate among the photogenic, supportive, and lens cells. There they form tuft‐like clusters of nerve endings, some of which contain dense‐cored vesicles. None of these endings was seen to penetrate the basal lamina and make direct intercellular contact with either a supportive cell or a photogenic cell. From these observations, it is concluded that the nerves end outside of the basal lamina surrounding photogenic, supportive, and lens cells. Adhesion sites, which may indicate chemical synaptic contact, were occasionally observed among these neural components.The photophores of the CaliforniaPorichthys notatusoften bioluminesce following intraperitoneal injection of the fish with epinephrine. It therefore appears from experimental, anatomical and fine structural evidence, that these luminescent organs are innervated and controlled by the sympathetic nervous sys

ISSN:0003-276X    

DOI:10.1002/ar.1091640405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractRats, having been given a single subcutaneous injection of testosterone propionate at four days of age, exhibited polyfollicular ovaries, extensive stratified squamous uterine metaplasia and persistent vaginal cornification (90–95% of the smears contained cornified cells) after adulthood was attained. If early androgentreated rats were blinded at 22 days of age the number of vesicular follicles in the ovaries of adults was greatly diminished, the incidence and extent of stratified squamous metaplastic lesions were suppressed and the number of vaginal smears containing cornified cells was reduced by about 50%. The effects of blinding, however, were negated by pinealectomy illustrating that the suppressive influence of light deprivation on reproduction was mediated by way of the pineal glan

ISSN:0003-276X    

DOI:10.1002/ar.1091640406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091640407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091640408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY