摘要:

AbstractIn the testes of man and some other mammals a structure is formed during reproductive age, designated a “receptacle”. This structure which is not present during infancy represents the first communication of the seminiferous tubules to an extragonadal organ the rete “organ,” the receptacles received the mature spermatozoa which later are transported to the mesonephric excretory duct through the rete tubules. The receptacles are the distal end of the rete tubules and are considered as coelomic funnels.The epithelium of the receptacles, the tubuli recti and rete tubules is identical in infantile and mature testes and of a different type than the epithelium of the seminiferous tubules.The receptacle consists of a distal dilatation of the tubuli recti in which the seminiferous tubule invaginates following the ruptures of their walls. Identical receptacles are present in man, horse (Equus caballus), armadillo (Dasypus novemcinctus mexicanus), white‐tailed deer (Odocoileus virginianus), dog (Canis familiaris), cat (Felix domesticus), hamster (mesocricetus auratus) and woodhuck (Marmota monax). In the mule (sterile offspring of a mare and a jackass) the receptacles lack communications.The presence of mature spermatozoa is believed to be the proper stimulus for the formation of the receptacles which established the communications between the seminiferous tubules and the rete tubules.The receptacles, tubuli recti and rete testis are part of an organ which accomplished the connection of the gonad to its mesonephric excreto

ISSN:0003-276X    

DOI:10.1002/ar.1091480102

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

年代:1964

数据来源: WILEY

摘要:

AbstractThe A‐V node of the dog is composed of closely interwoven fibers which frequently connect with each other within a sparse collagen framework. Fibers from the interatrial septum enter the posterior half of the node along its superior and posterior margins, while the anterior half of the node is isolated from such connections. In addition there are fibers from the interatrial septum which bypass these marginal atrionodal junctions and instead enter the convex surface of the node, which lies beneath the right atrial endocardium. These bypassing fibers circumvent most of the interweaving fibers within the A‐V node. At the posterior margin of the node, lying between it and the coronary sinus, there are ganglia and nerves, with the nerve fibers extending anteriorly through the A‐V node into the A‐V bundle. The only major anatomic difference between the human and canine A‐V nodes is their arterial blood supply, that of man being derived from one source originating from the right coronary artery and that of the dog being from two sources, both of which originate from the left corona

ISSN:0003-276X    

DOI:10.1002/ar.1091480103

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

年代:1964

数据来源: WILEY

摘要:

AbstractThymus of guinea pigs and C3H mice was fixed in 1% osmium tetroxide, embedded in Araldite or Maraglas, and studied under the electron microscope.Hassall's corpuscles showing the typical concentric, lamellated pattern are observed. Reticular cells form layers around central elements of variable appearance. One or more reticular cells or cystic structures often constitute the centers of corpuscles. Nuclear degeneration, swollen cytoplasm, and intracellular fibrils are characteristic findings. Desmosomes may be quite numerous and may cover a large portion of a cell's surface. Intracellular fibrils are particularly dense at membranous sites and often are apparently unrelated to desmosomes. Reticular cells at the periphery of thymic corpuscles may be contiguous with cells of the cytoreticulum. Many reticular cells contain organelles generally associated with protein synthesis or active transport.Intercellular and intracellular cysts are regularly seen and are frequently related to thymic corpuscles. Some cysts may be manifestations of cell synthesis and storage.The epithelial nature of thymic corpuscles and cysts is evident. Thymic corpuscles may arise by localized collapse of the cytoreticulum.

ISSN:0003-276X    

DOI:10.1002/ar.1091480104

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

年代:1964

数据来源: WILEY

摘要:

AbstractThe perineal pigment spot of the C57 Black mouse was examined macro‐ and microscopically in animals ranging in age from 14 days post‐fertilization to 28 days post‐parturition. Dendritic pigment‐containing cells first become evident in the dermis of the area on the sixteenth day post‐fertilization. Throughout later stages of development, these pigmented cells continue to be restricted to the dermis of this area. Since the dopa treatment reveals the presence of a melanin synthesizing system within these cells, they are true melanocytes which have become restricted to this layer of the integument.Histological examination reveals a population of melanocytes in the epidermis and/or hair follicles also. These are rarely found over the center of the area but are seen in increasing numbers laterally from the ventral midline. In contrast, dermal melanocytes are heavily concentrated near the ventral midline but decrease in numbers laterally. There are, therefore, two opposing but complementary gradients of melanocytes in the integument of the pigment spot. This suggests the possibility that a precocious differentiation of the basement membrane in this area during embryonic development inhibits the passage of melanoblasts into the epidermis thereby causing them to be restricted to t

ISSN:0003-276X    

DOI:10.1002/ar.1091480105

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

年代:1964

数据来源: WILEY

摘要:

AbstractNeuroanatomical nuclear configuration corresponding to the projection regions for the chorda tympani, the IXth, and the lingual nerves was studied in the cat thalamus by a combination of electrophysiological, stereotaxic, and histological techniques. Each of the three nerves innervating the tongue was dissected for stimulation in cats deeply anesthetized with Nembutal. Maps of the extent of the thalamic projection for a particular nerve were obtained by recording evoked potentials in the thalamus during the stimulation of one of these nerves. Such maps were correlated with the anatomical structures of the cat thalamus by reconstructing the recording sites from histological sections of the cat brain. It was found that the chorda tympani and the IXth nerve projection regions correspond closely to the ventromedial nuclear complex with slight encorachment on the lingual nerve projection region in the ventrobasal complex. The most medial portions of the taste nerve projection regions do not relay any tactile afferent impulses and the most lateral portion of the lingual nerve projection is not activated by impulses in the taste nerves. Therefore, it is suggested that the thalamic relay of taste is not coextensive with other lingual modalities in the cat thalamus but it has an independent representation in the ventromedial nuclear complex.

ISSN:0003-276X    

DOI:10.1002/ar.1091480106

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

年代:1964

数据来源: WILEY

摘要:

AbstractAnalysis of age changes in physical characteristics of mouse limb bones requires a sensitive, consistent and relatively simple apparatus for determination of transverse breaking strength. The developed instrument is essentially a one meter counter‐balanced 4‐to‐1 lever with a tracked, motor‐driven weight on its upper surface. At the beam's short end a loading tool impinges upward on a bone mounted in an adjacent holder; at the opposite end is a mercury switch connected to a relay halting the weight motor when fracture occurs. Bones, with proximal ends embedded in convex securing blocks of impression medium, may be positioned in a standard relationship to the holder, loading tool edge, and the balanced beam.Repetitive loading of a steel spring indicates instrument error of 1.8%. Preliminary tests with a random series of paired mouse femora show no significant difference between left and right bones. In the long‐term study it will be possible to correlate physical strength with other characteristics of opposite bones.An air‐gap capacitor across loading tool and bone holder and coupled to a variable frequency oscillator permits monitoring of specimen elasticity on a strip‐c

ISSN:0003-276X    

DOI:10.1002/ar.1091480107

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

年代:1964

数据来源: WILEY

摘要:

AbstractElectron microscopic studies reveal that the red pulp of the rabbit spleen is composed of reticular cells, reticulum and elements of the blood circulating through it. The three types of reticular cells described follow no definite pattern as to types of spaces they line and are not always adjacent to a basement membrane. Similar or dissimilar cells may line a basement membrane on the same or opposing sides. The entire red pulp area is intercommunicating through pores and junctions of the several spaces and in that area in which no basement membrane exists, the cytoplasmic projections of the reticular cells form a meshwork of spaces. Terminal arterioles are seen to end in collapsed type channels with a change from endothelium to Type I reticular cells. These rapidly join dilated areas. The reticular network of the spleen appears as four types: homogeneous, fibrillar, a combination of these, and reticular cells only. Isolated cilia are found in the reticular cell cytoplasm and are shown to be associated with a basal body and a centriole. The investigation supported the hypothesis that the red pulp of the spleen in the adult rabbit is a functionally dynamic area constantly changing its histological structure, both regarding cells and state of the vascular channels.

ISSN:0003-276X    

DOI:10.1002/ar.1091480108

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

年代:1964

数据来源: WILEY

摘要:

AbstractA malformed human fetus with multiple congenital anomalies including absence of an umbilical artery is described. These anomalies include malpositioning of the apex of the heart; a “mirror image” position of the liver; mal‐rotation of the gut with absence of external demarcation into small and large intestine; failure of development of the cloacal region with imperforate anus and absence of a urethra; undescended testes and bilaterally mal‐placed scrotal sacs, but the presence of a median phallus in spite of the failure of the ventral abdominal wall to develop fully.Factors known to influence the production of fetal anomalies in man and animals are discussed and a brief review of the literature on single umbilical arteries, which are known to be associated frequently with congenital anomalies, i

ISSN:0003-276X    

DOI:10.1002/ar.1091480109

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

年代:1964

数据来源: WILEY

摘要:

AbstractThe excessive growth of fatty tissue around atrophic organs has been described in humans as “hypertrophy ex vacuo”. Since adipose tissue receives its blood supply from smaller branches of arteries which also supply organs or muscles, it has been suggested that increased amounts of blood could be diverted from the inactive organs to the surrounding fatty tissue and promote its growth. This theory was investigated, using rats and mice of different strains. One testis, the artery of which also supplies the epididymal fat pad, was removed, and the animals sacrificed 3‐4 weeks later. Growth of the affected fat pad in both rats and mice of normal body composition was significantly reduced. Removal of the testis in adult yellow‐obese mice during periods of weight gain produced a moderate but significant weight increase of the affected f

ISSN:0003-276X    

DOI:10.1002/ar.1091480110

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

年代:1964

数据来源: WILEY

摘要:

AbstractNOrmal and atypical follicular structures were classified and counted in the ovaries of guinea pigs 3 to 11 weeks of age. The per cent of primary and secondary follicles remain almost constant throughout the period of observation. Corpora lutea appeared at the fifth week and reached what appeared to be the mature level by the sixth week. The per cent of follicles having polynuclear ova reached an early peak at four weeks and decreased sharply at five weeks postpartum. The per cent of polyovular follicles increased to a low peak at nine weeks and decreased in frequency thereafter. The frequencies of atretic follicles with polynuclear ova and of quency thereafter. The frequencies of atretic follicles with polynuclear ova and of atretic polyovular follicles were significantly higher than that of atretic normal follicles. The results of this study were compared to simular observations on the Swiss mouse, Golden Hamster and Sprague‐Dawley rat. The data were discussed in relation to gonadotripic hormone level

ISSN:0003-276X    

DOI:10.1002/ar.1091480111

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

年代:1964

数据来源: WILEY