ISSN:0002-9106    

DOI:10.1002/aja.1001160102

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

年代:1965

数据来源: WILEY

摘要:

AbstractPortions of the labyrinth or villi of placentas from late pregnancy from nine species in four orders of mammals were examined with the electron microscope. Pronounced patterns of layering of the trophoblast were found in these placentas which were all of the hemochorial type. The laboratory rat, laboratory mouse, hamster, and deer mouse have three layers of trophoblast between the maternal blood space and fetal vessels (hemotrichorial), the rabbit two layers (hemodichorial), the guinea pig and chipmunk one layer (labyrinthine hemomonochorial), and the human and armadillo one layer (villous hemomonochorial).The outer layer of trophoblast of the hemotrichorial placentas (the layer next to the maternal blood) is cellular, but the next two layers are apparently syncytial and are closely apposed to one another. The outer layer of the rabbit placenta is syncytial, while the inner layer contains some pockets of cells. In all of the hemomonochorial placentas examined, the continuous layer of trophoblast was syncytial. It was found that the surface layer of trophoblast of all the placentas studied is rich in granular endoplasmic reticulum, whereas in subsequent layers this element is less abundant. All of the placentas show both surface and basal modifications of trophoblast, but caveolae (pinocytotic vesicles) were found to be most commonly located in crypts, pockets, or other regions somewhat removed from the surface. It is suggested that an area of relative stasis of maternal plasma may be important for absorption of some substances by the placenta.

ISSN:0002-9106    

DOI:10.1002/aja.1001160103

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

年代:1965

数据来源: WILEY

摘要:

AbstractBilateral symmetrical electrolytic lesions were placed in the supraoptic, ventromedial and mamillary areas in groups of albino rats weighing 50, 100, 150, 200, 250 and 300 gm.The localization of the lesions was correlated with the coordinate setting used with the stereotaxic instrument.The diagrams presented contain the data for the antero‐posterior, lateral and dorso‐ventral coordinates plotted against the body weight of the respective groups and allow the extrapolation of coordinates for other hypothalamic structu

ISSN:0002-9106    

DOI:10.1002/aja.1001160104

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe gross and microscopic innervation of the bifurcation and extrapulmonary portion of the pulmonary artery in the adult cat is described. Morphopharmacologic studies indicated that the major efferent and afferent innervation is contributed by the right recurrent cardiac nerve, a branch of the recurrent laryngeal.A morphologic description of the adventitial nerve bundles, preterminal axon plexus and medial, fine unmyelinated neurites as seen in methylene blue and Bielschowsky silver preparations is given. Rare, classical, pressoreceptor arborizations of de Castro type II were identified, but evidence was presented of degenerative and regenerative neural activity in the adventitial and pre‐terminal plexus manifested by irregular axonic swellings, myelin ellipsoids with vacuolation, terminal growth cones and collateral sprouting. In these degenerative zones, the plexus assumed a more discontinuous organization showing features very suggestive of a simple pressoreceptor system composed predominantly of de Castro type I terminations.Thein vitropharmacologic studies using the isolated pulmonary artery‐nerve preparation confirmed the existence of effector, vasoconstrictor adrenergic sympathetic fibers in the recurrent cardiac nerve. Small unmyelinated perivasal and perivasal collateral fibers disappear or show severe degenerative changes following bilateral sympathectomy, and are considered to represent the sympathtic autonomic compon

ISSN:0002-9106    

DOI:10.1002/aja.1001160105

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe rete mirabile cerebri and the hypophysial vascularization were studied by various injection and staining techniques. The rostral hypophysial arteries arose bilaterally from the arterial circle of the cerebrum, while the caudal hypophysial arteries arose from the rete miabile on the dosal and caudal surfaces of the gland. The ramifications of the rostral hypophysial arteries supplied the vascular structures in the hypophysial stalk, which were classified on the basis of their structure into three groups; arborization forms, spike forms, and capillary loops. These structures drained into large portal vessels leading to the pars distalis. The pars distalis received a second smaller group of portal vessels from the capillary bed of the lower infundibular stem. The small group of portal vessels was limited in its extent by a well‐developed hypophysial cleft. No direct arterial supply to the pars distalis could be demonstrated. The findings of this study support the view that the blood in the hypophysial portal system flows distally from the hypophysial stalk to the pars distali

ISSN:0002-9106    

DOI:10.1002/aja.1001160106

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

年代:1965

数据来源: WILEY

摘要:

AbstractSectioned as well as negatively stained preparations of developing myotomal cells from the chick embryo were studied with the electron microscope. The application of these two techniques to similar material made it possible to observe developing muscle cells in successive stages of differentiation and at the same time visualize some of the isolated components making up these cells.The thick and thin filaments observed in the embryonic muscle were morphologically indistinguishable from those observed in adult muscle. The thin filaments, found randomly dispersed in the cytoplasm of the early cells, were present in large concentrations before the first appearance of thick filaments. The first observed thick filaments had lengths of 1.5 μ, equal to that of adult thick filaments. The appearance of large polyribosomes was correlated with the first appearance of the thick filaments. Single and small groups of ribosomes were always present. Early formed thick and thin filament aggregates were found in the same hexagonal array that is typical to the organization of myofilaments in adult myofibrils. Non‐striated myofibrils, associated with a periodic transverse tubular system, were found before striated myofibrils could be observed. Some preliminary observations were made concerning the appearance of glycogen particl

ISSN:0002-9106    

DOI:10.1002/aja.1001160107

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe arterial plan of the head and neck of 64 immature rhesus monkeys (Macaca mulatta) was studied using four techniques — dissection, corrosion preparations, cleared specimens, and angiographs. In general, the arterial plan of this area in the monkey is similar to that of man. However, certain outstanding differences were noted. The origin, course, and distribution of all arteries is described as well as the vascular relations to pertinent structure

ISSN:0002-9106    

DOI:10.1002/aja.1001160108

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe cetacean humerus is a short, robust bone without an open medullary cavity. It lies in the base of the resilient, streamlined pectoral limb (flipper) between the only free articulation (the glenohumeral) and approximately the body contour. The humerus is acted upon by muscles of the shoulder complex and receives loadings from the flattened distal portion of the limb as this hydroplane acts against body inertia and water resistance in control of body attitude.This study is an analysis of development and structure of the humerus in terms of the unique functional role of the flipper of finback, beluga and pilot whales. Gross external and internal architecture are depictued by photographs and by whole bone and frontal section radiographs. Structural density (bone/unit volume of humerus, with mineral content known to be constant) is analyzed indirectly by photodensitometry of standardized radiographs of sawed sections. Results are shown in graphic reconstructions of sections and of the whole bone. By comparison of radiodensity with the actual weight/volume of excised samples, sections are also reconstructed in terms of absolute density distribution.It is found that the spongy cetacean humerus, from its origin, is without central resorption and that its definitive structure is produced primarily by differential concentration of bone along endoectad gradients of porosity. Thus, the greatest concentration of bone is on medial and lateral sides while bone only half as dense fills the anterior and posterior sides and underlies the most dense regions. The core region is extremely porous. Within the biological context, this is a most reasonable approximation of the engineered box‐beam as employed in some aircraft wings. Whole bone and frontal section radiographs show that, within this overall density pattern, the distribution of bone trabeculae resembles the classic illustrations of trajectories in the loaded beam.The ontogenetic and phylogenetic factors with possible bearing on this type of bone development and structure are discusse

ISSN:0002-9106    

DOI:10.1002/aja.1001160109

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

年代:1965

数据来源: WILEY

摘要:

AbstractDorsal and ventral roots were dissected bilaterally on spinal cords of adult monkeys: six rhesus, six irus and three baboons. Measurements made were: the distance between the uppermost cord attachments of successive nerve roots (segment length); the distance between the uppermost and lowermost fila within each root (root attachment length); and the distance beween the lowermost fila of one root and the uppermost fila of the subjacent root (interroot length). Segment lengths, dorsally and ventrally, are essentially alike within each species. In rhesus the average at various levels ranges from 4½ mm in cervical and sacral to 12½ mm in lower thoracic; in irus, from 4 mm in cervical and sacral to 10 mm in lower thoracic; in the baboon, from 5½ mm in cervical and sacral to 19 mm in lower thoracic. Within each species the dorsal and ventral root attachment lengths are similar, as are the interroot lengths, except in the lower thoracic levels. There dorsal interroot lengths range up to 3 mm longer than ventral. Cross sectional areas of the various levels were planimetrically determined. Within each species the largest areas are at lower cervical and lower lumbar levels. Individual segment volumes were calculated. In rhesus and irus these vary only about 60 mm3from the largest to the smallest segment, excluding sacrocaudal levels. In baboon this difference is as much as 260 m

ISSN:0002-9106    

DOI:10.1002/aja.1001160110

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

年代:1965

数据来源: WILEY

摘要:

AbstractCytological changes in uterine stromal cells of the rat during induced primary decidua formation have been examined electron microscopically. Decidua forming stroma was examined at daily intervals for the five days during which the reaction reaches maximal hypertrophy and hyperplasia and was compared with pseudopregnant, non‐decidual (control) endometrium. Stromal cells of control uteri resemble embryonic fibroblasts. They appear to be of two types, depending on whether they contain rough – or smooth‐surfaced endoplasmic reticulum. As the decidual reaction progresses, the cells enlarge and become binucleate; cells which contain exclusively rough surface endoplasmic reticulum no longer are evident. Glycogen and fat become abundant, the former in association with smooth‐surfaced membranes of the endoplasmic reticulum. Mitochondria become more numerous, smaller, and show evidence of a rearrangement in internal organization. There is a pronounced increase in a fine intracytoplasmic fibrillar component; and a spectrum of “microbodies” and lysosomes appears. At the height of the reaction, the stroma appears epithelioid. The possible functional significance of these changes i

ISSN:0002-9106    

DOI:10.1002/aja.1001160111

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

年代:1965

数据来源: WILEY