bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aspects of the ultrastructure of the alimentary canal and respiratory ducts in Xenopus laevis larvae
Authors: Fox H. , Bailey Elaine , Mahoney R. 
Published: February 2005

AbstractThe pharynx, intestine and respiratory duct of Xenopus laevis were examined by light and electron microscopy, at different stages of the metamorphic cycle, through climax.It is well known that preclimactic larvae are suspension feeders and that after climax specimens feed on solid food. It is shown that the histology of the pharynx and the alimentary canal changes in adaptation to the change in the mode of feeding.Suspension feeding utilises ciliary activity but after climax cilia have disappeared from the pharynx and alimentary canal, when new neuromuscular mechanisms are utilised in feeding.Other morpho‐histological changes in various intestinal and respiratory tissues are likewise considered in terms of functional activity.
The maxillae of Drosophila melanogaster as revealed by scanning electron microscopy
Authors: Harris William A. 
Published: February 2005

AbstractThe scanning electron micrographs show the external morphology of the maxillae of Drosophila melanogaster. Specifically, they illustrate the patterning of the different types of chemo‐receptive sensilla on the maxillary palpi making possible a clearer understanding of the structure of the tiny maxillary lobes. It appears that the maxillary lobes act as “cleaning brushes” during the feeding process.
Evidence for amylase in avian salivary glands
Authors: Jerrett Steven A. , Goodge William R. 
Published: February 2005

AbstractFour glands of the house sparrow, chicken and turkey were examined histologically and for their content of amylase. These were the external and intermediate mandibular glands, the maxillary gland and glandula anguli oris of the sparrow and the anterior and posterior mandibular, maxillary and anguli oris glands of the chicken and turkey. Amylase was determined by a starch substrate slide method and by biochemical assay. General morphology and mucopolysaccharide staining are described.All four glands of the sparrow demonstrated significant amylolytic activity by the assay. In the external mandibular and anguli oris glands this activity could be traced to mucous and seromucous cells of origin by means of the starch substrate slide procedure. None of the glands of the chicken or turkey displayed significant amylolytic activity.
Skeleton and musculature of the head and thorax of Trichoplusia ni (Hubner), (Lepidoptera: Noctuidae)
Authors: Macfarlane John , Eaton John L. 
Published: February 2005

AbstractThe muscles of the head, neck and thorax of the adult cabbage looper Trichoplusia ni are described for the first time. They are compared to those of Choristoneura fumiferana, Manduca sexta, Smerinthus geminatus, Antheraea polyphemus, Sphinx convolvuli, Crymodes devastator, and Danaus plexippus.
Morphological differences between the Teleosts Couesius plumbeus (Lake chub) and Rhinichthys cataractae (Longnose dace) and their hybrids from Alberta
Authors: Nelson Joseph S. 
Published: February 2005

AbstractMarked external and osteological differences exist between the related cyprinids Couesius plumbeus and Rhinichthys cataractae. C. plumbeus differs from R. cataractae in several external features, such as eye size and mouth shape, any one of which permits identification of individuals. C. plumbeus has postcleithral and nasal bones while R. cataractae does not. Many differences in bone shape also exist. Natural hybrids between the two species from Upper and Lower Kananaskis reservoirs, southwestern Alberta, are intermediate in the average of their external and osteological characters. Some characters in the hybrids, however, are so variable that they fall within the range of both parental species. An individual hybrid may resemble one parental species in one diagnostic character and the other parental species in another. The largest individuals known of the three forms from the Kananaskis system are hybrids.
Musculature and innervation of the neck of the desert locust, Schistocerca gregaria (Forskål)
Authors: Shepheard Peter 
Published: February 2005

AbstractThe innervation of each of the muscles involved in mediating head movement in the desert locust Schistocerca gregaria is described in detail. The number of motor neurones to each muscle and the neutral pathway and ganglion of origin of each are deduced from both histological and electrophysiological evidence. Only two of the muscles are, on histological evidence, innervated by as few as four different neurones, while several receive more than ten, and one at least 13. Individual muscles are shown physiologically to receive, in a few cases, as many as six different motor neurones. At least six muscles are innervated by motor neurones originating in more than one ganglion. One group of four muscles consisting in total of less than 100 muscle fibres receives more than 20 different motor neurones from three different ganglia through three or four different nerve roots. In these muscles, many single muscle fibres receive innervation from at least two different ganglia. It is concluded that the segmental nature of an insect muscle can not be deduced solely from a knowledge of the ganglion of origin of the motor innervation to that muscle. The innervation patterns that exist today must reflect past evolutionary development, but changes in the peripheral distribution of motor neurones, or migration of motor neurone cell bodies from one ganglion to another, or the development of additional motor neurones, or several of these factors together, must have formed a part of that development.
Ultrastructural evidence for the existence of two types of neurosecretory cells in the abdominal ganglia of the chelicerate arthropod, Limulus polyphemus
Authors: Herman William S. , Preus Doris M. 
Published: February 2005

AbstractEvidence suggesting the existence of two types of neurosecretory cells in each abdominal ganglion of Limulus polyphemus has been obtained by light and electron microscopy. After Helly fixation the two cell types are readily distinguished from other neurons by the Azan method, but they react weakly when stained by paraldehyde fuchsin. Type I cells are larger, more regular in shape, and found more anteriorly in each ganglion. They contain apparently cylindrical secretory granules, many dictyosomes, and numerous cytoplasmic vesicles. Type II cells produce spherical granules, contain fewer dictyosomes, have less conspicuous cytoplasmic vesiculation and possess more prominent parallel arrays of rough endoplasmic reticulum. Granules similar to those found in both cell types are present in the neuropile and certain nerves, but the specific pathways of the axons of these cells have not yet been determined.
Structure and function of rectal pads in Blattella and Blaberus with respect to the mechanism of water uptake
Authors: Wall Betty J. , Oschman James L. 
Published: February 2005

AbstractThe morphology of the rectal pads of two cockroaches, Blattella germanica and Blaberus giganteus is described and contrasted with that of Periplaneta americana, studied previously. The columnar absorptive cells of the three species are similar in structure. However, Blattella and Blaberus rectal pads have a second type of cell, termed the secondary cell, that is not present in Periplaneta. The secondary cells are embedded in the pad epithelium and have crypts of cavities opening into the subepithelial sinus. In addition, a multilayered sheath is present between the pad cells and the sinus. The sheath acts as a barrier, perhaps of low permeability, between the subepithelial sinus and the pads. It is interrupted only at the borders of the secondary cells. A mechanism for fluid absorption is presented and the possible role of secondary cells is discussed. It is proposed that the secondary cells reabsorb solute from the sinus and that this solute can then be recycled through the pad cells. Structures resembling neurosecretory terminals within the cavities of the secondary cells may be involved in regulation of recycling. The arrangement of the rectal pads in these insects has structural and perhaps functional similarities with other transporting systems, particularly the cryptonephric system.
Potassium pyroantimonate and osmium‐zinc iodide reactivity in the tubular epithelium of the opisthonephric kidney of the sea lamprey, Petromyzon marinus L
Authors: Youson John H. 
Published: February 2005

AbstractPyroantimonate precipitate indicates that the epithelium of the proximal tubule is the only segment of the tubular nephron of the fresh water lamprey where large accumlations of cations are distributed. Unusually large amounts of reaction product are located within the lateral intercellular spaces and within vesicles closely associated with the plasma membrane at the lateral and basal surfaces. This technique suggests the continuity of these vesicles with the plasma membrane and alludes to the possibility of an endomembranous system of vesicles and the intercellular spaces as vehicles for ion transport. Lateral intercellular spaces of proximal tubules of lower vertebrates may play a different role in kidney function that their counterparts in higher vertebrates.Osmium‐zinc iodide has a specificity for certain cells within the proximal, intermediate, and distal segments, but no structural differences are noted when these cells are compared to unstained cells. Smooth endoplasmic reticulum remains unstained in the distal segment but the stain has a strong affinity for elements of the Golgi apparatus, lysosomes, and the nuclear envelope of all cell types. This technique does not suggest a structural or functional similarity between cells of the distal segment and the chloride cells of the gills of teleosts.
Functional anatomy of pulmonary ventilation in the garter snake, Thamnophis elegans
Authors: Rosenberg Herbert I. 
Published: February 2005

AbstractThe functional anatomy of pulmonary ventilation in Thamnophis elegans was studied by electromyography. Flow of air into and out of the lungs follows a triphasic pattern and occurs while the glottis is held open by a dilator muscle. Non‐ventilatory rest periods characterized by a closed glottis and lack of ventilatory movements occur between breaths. Exhalation is caused by contraction of a pair of dorsolateral sheets of muscle that extends from the ventral surface of the vertebral column to the medial surfaces of the ribs and a pair of ventro‐lateral sheets that extends from the medial surfaces of the ribs to the mid‐ventral skin. Inspiration is powered by contraction of a series of rib levators and retractors. The last phase of the ventilatory cycle is a passive expiration that may be caused by elastic recoil of the walls of the filled lungs and relaxation of muscles used during inspiration. The site of respiratory pumping is shifted craniad after large prey items have been completely ingested. The significance of this shift and its anatomical basis are considered.
Morphological and histochemical features of the duodenal glands in six marsupial species
Authors: Krause William J. 
Published: February 2005

AbstractThe duodenal glands of four marsupial species, the kangaroo, native cat, marsupial mouse, and bandicoot, form a narrow lobular collar immediately distal to the gastrointestinal junction. In two species, the koala and wombat, the duodenal glands are diffuse and scattered along the intestinal tract distal to the gastrointestinal junction for considerable distances. The glands of all species examined empty independently into the intestinal lumen. Histochemical studies indicate that the latter two species, the koala and wombat, elaborate an acid mucin whereas the former species produce a neutral mucosubstance. Ultrastructural examination shows that generally the duodenal glands are comprised of large pyramidal cells that show a definite polarity, with basally‐placed nuclei and apically‐situated secretory granules. Species differences, with regard both to the morphology and nature of the secretory granules and to the proportions of cell organelles, exist. The diversity of diet between species is discussed.
Vascular supply to the ventral pelvic region of anurans as related to water balance
Authors: Roth Jan J. 
Published: February 2005

AbstractThe ventral pelvic integument of anurans in hypervascular as compared to other skin regions. Recent studies indicate that this area is primarily responsible for water uptake and rehydration. Nine species representing four genera of terrestrial and aquatic Anura were dissected for comparison of vascularity in the pelvic area. Major differences in the ventral pelvic integumental vessels were found between aquatic and terrestrial genera. These variations are described, and names are suggested for previously unnamed vessels. Changes in vascularity are discussed and related to the literature on Anura pertinent to rehydration rates, tolerance of desiccation, resistance to desiccation, and habitat.Data from this study and previous studies suggest a correlation among the parameters discussed and habitat. The suggestion is made that when species are classified as xeric, mesic, or aquatic on the basis of the habitat in which they live, their responses to rehydration, tolerance to desiccation, and vasculatity should be considered, as these characteristics more accurately represent the micro‐habitat.
The distribution of smooth muscle in the cat ovary with a note on its adrenergic innervation
Authors: Burden Hubert W. 
Published: February 2005

AbstractSmooth muscle in the ovaries of estrus and anestrus cats was studied with the TP‐Levanol Fast Cyanine 5 RN technique and adrenergic nerves were visualized with the Falck‐Hillarp fluorescence procedure. Numerous bundles of smooth muscle fibers were observed in the mesovarium, and the hilar, medullary, and cortical regions of the estrus ovary. Also, theca externa of large vesicular follicles contained many smooth muscle fibers. Adrenergic nerves with varicosities were present in ovarian perifollicular tissue. Anestrus animals had a reduced number of cortical and perifollicular muscle fibers and the intensity and density of fluorescent nerves was reduced. It is suggested that contraction of ovarian smooth muscle facilitates ovulation. These contractions may be, at least partially, under local neural control.
The chicken trigeminal ganglion I. An anatomical analysis of the neuron types in the adult,
Authors: Gaik Geraldine C. , Farbman Albert I. 
Published: February 2005

AbstractAn anatomical analysis of the chicken trigeminal ganglion was made using light microscopy on specimens prepared by usual chemical fixation or freeze‐drying methods and by electron microscopy. Two types of neurons were consistently seen, dark and light cells. Dark cells contained a dense cytoplasm with Nissl substance distributed evenly throughout, whereas light cells had a less dense cytoplasm containing clumps of Nissl substance. The Nissl bodies in light cells contained only a few small cisternae of granular endoplasmic reticulum as compared with many stacked cisternae in Nissl bodies of dark cells. The ratio of dark to light cells was approximately 62:38 in all regions of the ganglion. Dark cells were consistently smaller than light cells. In the seven‐day old chick, the mean diameters of the dark and light neurons were 21.4 μ and 29.5 μ respectively; in the adult the values were 29.9 μ and 39.7 μ respectively. It is concluded that the dark and light cells belong to two distinct neuronal cell populations.
The relationship of acetylcholinesterase activity to optic fiber projections in the tiger salamander Ambystoma tigrinum
Authors: Gruberg Edward R. , Greenhouse Gerald A. 
Published: February 2005

AbstractIn the tiger salamnder the distribution of optic fibers, as revealed by the Fink‐Heimer method, is compared with the localization of acetylcholinesterase, as revealed by histochemical methods. AChE activity coincides with optic nerve axons in the optic fiber layer of the retina, in the optic nerve, in the optic tracts and in every optic projection. Reginons of optic fiber terminals show heavier activity than optic fibers of passage. Comparison with other vertebrates is also made.
Retinal projections in a snake, Thamnophis sirtalis
Authors: Halpern Mimi , Frumin Natalie 
Published: February 2005

AbstractThe retinofugal projections of the snake Thamnophis sirtalis were studied by the method of experimentally induced Wallerian degeneration stained by the Fink‐Heimer method. The retinal ganglion cells project to all parts of the contralateral lateral geniculate complex, nucleus lentiformis mesencephali, nucleus geniculatus pretectalis, nucleus posterodorsalis, basal optic nucleus and superficial layers of the optic tectum. In addition, the retinofugal projections were observed terminating in portions of the ipsilateral lateral geniculate complex and nucleus posterodorsalis.Examination of the morphology of the retinal terminal areas stained for Nissl substance with cresyl violet led to the conclusion that these regions are well differentiated and should not be considered poorly developed when compared with other reptilian forms such as turtles.
Neuronal connections and the function of the corpora pedunculata in the brain of the American cockroach, Periplaneta americana (L.)
Authors: Weiss Mitchell J. 
Published: February 2005

AbstractThe fiber constituents and connections of the calyces — the input‐receiving regions — of the corpora pedunculata (“mushroom bodies”) were studied in reduced silver preparations from the American cockroach, Periplaneta americana (L.). In the outer synaptic layer of the calyces five fiber classes were distinguished, the first three of which arise outside the mushroom body. (1) Four highly similar neurons with somata near the optic lobe branch into different parts of the ipsiateral protocerebrum, including both calyces. Their fibers are highly constant in arrangement and position and contain small nucleus‐like bodies. (2) The tractus olfactorio‐globularis (sensu lato) emits fiber groups which course along the calycal walls as “calycal tracts” before ultimately dissipating into the synaptic layer. Variability within these tracts is described. (3) Fibers of undertermined origin outside the mushroom body radiate from the calycal center outwards through the synaptic layer. (4) From the inner calycal layer of neurites belonging to intrinsic mushroom‐body neurons, perpendicular collaterals enter the synaptic layer. (5) Intrinsic‐neuron somata near the calycal rim emit fibers which course tangentially within the synaptic layer from calycal rim to center. These fibers form a special peripheral zone in the pedunculus.The predominant presumably afferent calycal fiber class is that derived from the tractus olfactorio‐globularis. No evidence was found for tracts from optic lobe to calyces. On this basis, and in light of the experimental and comparative anatomical literature, it is suggested that the corpora pedunculata of P. americana and other pterygotes are fundamentally second‐order antennal sensory processing centers.Conflicting observations in earlier reports are critically discussed.
Ultrastructure of Lyonet's gland in the silkworm (Bombyx mori L.)
Authors: Waku Yoshio , Sumimoto Ken‐Ichi 
Published: February 2005

AbstractThe gland cells of Lyonet's gland, which is accessory to the silk gland in the silkworm larva, is characterized by the presence of complicated canaliculi bearing microvilli on their inner surface, large numbers of mitochondria and remarkably convoluted basal plasma membrane. On the other hand, the cell lacks the well‐developed cytoplasmic membrane system such as rough‐ and smooth‐surfaced endoplasmic reticula and Golgi bodies, though free ribosomes are numerous. Secretory vesicles are absent, and the canaliculi contain no dense material. From such ultrastructural observations, it was suggested that a possible role of the gland may be the exchange of the small molecules such as water and ions, rather than the hitherto supposed secretory role of a cementing sunstance of silk proteins. The lumen of the proximal part of the glandular duct contains a kind of proteinaceous substance which can be demonstrated histochemically and is regarded as similar to one of the silk proteins in the silk gland, not to the real product of the Lyonet's gland.
Relative thickness of the renal medulla in birds
Authors: Johnson Oscar W. 
Published: February 2005

AbstractThe intraspecific mean length of medullary cones in avian kidneys is analogous to medullary thickness in the mammalian kidney. Hence, relative medullary thickness (based upon kidney volume) can be calculated for birds as was done in mammals years ago. Comparative figures are given for 26 species from nine avian orders. The organizational pattern of cortex and medulla in the bird kidney is reviewed, and a simplified diagram of this relationship is presented. With some exceptions, urine concentrating ability and relative medullary thickness are directly proportional in mammals. Contrarily, no similar trend was evident in birds when current information on water economy was compared to relative medullary thickness in various species. There are a number of factors (such as the respective functional roles of reptilian and mammalian‐type nephrons, interspecific variations in ion transport, etc.) which require study before the significance of relative thickness in the avian medulla can be evaluated more thoroughly.
Horny cell formation in the epidermis of Rana pipiens
Authors: Lavker Robert M. 
Published: February 2005

AbstractWell preserved transitional cells were found between differentiated cells and horny cells of the frog epidermis, thus facilitating the study of the sequential events involved in horny cell formation. Autolysosomes appear to play an important role in the formation of horny cells. These structures preferentially digest those cytoplasmic components which are not necessary constituents of the terminal horny cell. The release of the contents of the small mucous granules into the intercellular spaces is one of the initial events in horny cell formation. Filaments and large mucous granules seem to be resistant to the lytic digestion and contribute to the bulk of the horny cell. Loss of fluids through the plasma membrane and consolidation of the remaining constituents, results in a flattened horny cell. The appearance of a thickened membrane around the horny cell signifies the completion of the transformation process.