bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vasculature of the head and respiratory organs in an obligate air‐breathing fish, the swamp eel Monopterus (=Amphipnous) cuchia
Authors: Munshi J. S. D. , Ghosh T. K. , Ojha J. , Olson K. R. 
Published: February 2005

AbstractMethyl methacrylate vascular corrosion replicas were used to examine the macrocirculation in the head region and the microcirculation of respiratory vessels in the air‐breathing swamp eel Monopterus cuchia. Fixed respiratory tissue was also examined by SEM to verify capillary orientation. The respiratory and systemic circulations are only partially separated, presumably resulting in supply of mixed oxygenated and venous blood to the tissues. A long ventral aorta gives rise directly to the coronary and hypobranchial arteries. Two large shunt vessels connect the ventral aorta to the dorsal aorta, whereas the remaining ventral aortic flow goes to the respiratory islets and gills. Only two pairs of vestigial gill arches remain, equivalent to the second and third arches, yet five pairs of aortic arches were identified. Most aortic arches supply the respiratory islets. Respiratory islet capillaries are tightly coiled spirals with only a fraction of their total length in contact with the respiratory epithelium. Valve‐like endothelial cells delimit the capillary spirals and are unlike endothelial cells in other vertebrates. The gills are highly modified in that the lamellae are reduced to a single‐channel capillary with a characteristic three‐dimensional zig‐zag pathway. There are no arterio‐arterial lamellar shunts, although the afferent branchial artery supplying the gill arches also supplies respiratory islets distally. A modified interlamellar filamental vasculature is present in gill tissue but absent or greatly reduced in the respiratory islets. The macro‐ and micro‐circulatory systems of M. cuchia have been considerably modified presumably to accommodate aerial respiration. Some of these modifications involve retention of primitive vessel types, whereas others, especially in the microcirculation, incorporate new architectural designs some of whose functions are not readily apparent.
Structure of the accessory reproductive glands of the male migratory grasshopper, Melanoplus sanguinipes
Authors: Couche Graham A. , Gillott Cedric 
Published: February 2005

AbstractThe accessory reproductive glands of Melanoplus sanguinipes comprise two bilateral masses of 16 tubules each, distinguishable in sexually mature insects as four white, ten short hyaline, one long hyaline, and a seminal vesicle. Over most of its length, the wall of each tubule consists of a simple glandular epithelium resting on a basal lamina, surrounded by a thin layer of circular muscle. However, near the junction with the ejaculatory duct, the wall of each tubule has a much thickened circular muscle layer and squamous or cuboidal epithelium, the region serving to regulate movement of secretion into the ejaculatory duct. Interdigitation of adjacent epithelial cells is common, and several kinds of specialized junctions occur. In the glandular region, all epithelial cells appear the same and may be flattened, cuboidal, or columnar depending on the tubule type. Except for those of the seminal vesicle, the glandular epithelial cells share ultrastructural features typical of cells engaged in the synthesis of protein for export. Despite these general similarities, in most instances subtle differences occur in the cellular ultrastructure of the epithelia of each tubule and in the appearance of their luminal secretions, suggesting that the tubules are functionally specialized.
Golgi study of the anterior dorsal ventricular ridge in a lizard. II. Neuronal cytodifferentiation
Authors: Díaz C. , Yanes C. , Medina L. , Trujillo C. M. , Monzón M. , Puelles L. 
Published: February 2005

AbstractThe development of the morphologic features of neurons in the anterior dorsal ventricular ridge (ADVR) has been followed in Golgi preparations from the lizard Gallotia galloti between embryonic stage 32 and post‐eclosion stages of specimens 3.6–4.5 cm in length. The differentiation sequence of multipolar and bitufted neurons was established. Dendritic growth cones are present after stage 34. Filiform dendritic processes are replaced later on by spines. Clusters of neurons first appear at stage 39 in the periventricular zone, the cells becoming Golgi‐impregnated in pairs. After hatching, the number of impregnated cells per cluster increases.
Structure of the temporal organ of the Japanese house centipede, Thereuonema hilgendorfi Verhoeff
Authors: Yamana Kenjiro , Toh Yoshihiro 
Published: February 2005

AbstractThe ultrastructure of the temporal organ of the Japanese house centipede, Thereuonema hilgendorfi Verhoeff (Chilopoda), has been examined. The temporal organ of this species is known to be a carbon dioxide receptor. It appears externally as a small protuberance with a small opening (5 μm) on its summit. There is a small cuticle‐lined cavity beneath the protuberance, and a mushroom‐shaped projection protrudes from the base of the cavity into its interior. Below the cavity is an encapsulated, bulb‐shaped cellular mass (sensory bulb), which contains about ten receptor cells and 100 supporting cells. Nuclei of both receptor and supporting cells occur basally in the sensory bulb. Each receptor cell has a single dendrite, which gives rise to a pair of sensory cilia. The cilia enter the mushroom‐shaped projection, and course along the inner surface of its calyx. The supporting cells have distal processes, which accompany the cilia into the calyx. The surface cuticle of the calyx consists of a fabric of fibrils, but in not layered like the cuticular integument. The fabric is permeable to water. The observed structure is discussed in relation to carbon dioxide reception and in comparison with the structure of olfactory receptors and hygroreceptors.
Comparative studies on the vascular organization of carotid labyrinths of anurans and caudates
Authors: Kusakabe Tatsumi 
Published: February 2005

AbstractThe three‐dimensional structures of the carotid labyrinth in five species of anurans representing four families (Rana nigromaculata, Rana catesbeiana, Bufo japonicus, Hyla arborea, and Xenopus laevis), and three species of caudates representing three families (Cynops pyrrhogaster, Hynobius nebulosus, Ambystoma mexicanum) were compared using vascular corrosion castings and scanning electron microscopy (SEM). Anuran carotid labyrinths are spherical in shape and are classified into two groups according to the origin of the external and internal carotid arteries. One group, which included Rana, Hyla, and Bufo, is characterized by the presence of a vascular ring at the proximal end and some vascular routes at the distal end of the labyrinth. The external and internal carotid arteries originate from these structures. The other group, which includes only Xenopus, is characterized by the external carotid artery opening directly from the central chamber or the common carotid artery, and by the internal carotid artery originating from within the vascular maze. The vascular maze is most complex in Xenopus, less so in Rana and Bufo, and simplest in Hyla. The carotid labyrinths in Cynops and Hynobius are oblong in shape. The fundamental organization in salamanders is similar to that in anurans. The vascular maze, however, is much simpler than in Hyla. There is no specialized swelling in Ambystoma mexicanum. The present findings suggest that most amphibian carotid labyrinths have the appropriate architecture for controlling vascular tone.
Functional organization of the arctiid moth tymbal (insecta, lepidoptera)
Authors: Fullard J. H. , Heller B. 
Published: February 2005

AbstractThe exoskeletal morphology, muscular organization, and innervation patterns of the tymbals of seven sound‐producing species of tiger moths (Arctiidae) were compared with the undifferentiated episterna of two silent species. At least three muscles are involved in sound production: the tymbal muscle, pv2, and the accessory muscles, pvl and/or pv6. All of the tymbal muscles are innervated by the IIIN2a branch of the metathoracic leg nerve, which contains two axons larger than the others. Backfills of the tymbal branch of the IIIN2a reveal a medial sensory neuropil and a population of five ipsilateral motor neurons whose somata are clustered into three groups along the anterior edge of the metathoracic ganglion. The dendritic arborizations of the motor neurons extend to the ganglionic midline but are separate from one part of the auditory neuropil observed in other noctuoids. The study concludes that the arctiid tymbal reveals only minor modifications (e.g., cuticle thinning) of the episterna of silent moths and represents a primitive form of the tymbal compared to those of the Cicadidae.
The chiton gill: Ultrastructure in Chiton olivaceus (Mollusca, Polyplacophora)
Authors: Fischer Franz Peter , Alger Monika , Cieslar Daniela , Krafczyk Hans‐Ulrich 
Published: February 2005

AbstractGills of Chiton olivaceus, a primitive mollusc, are relatively simple in their structure and ultrastructure but are well adapted to a life in the intertidal zone. In contrast to some other molluscs, there is no differentiation of the gill epithelium into functional regions other than respiratory ones. Ciliation of the epithelium in certain areas may optimize water flow from the outer to the inner part of the mantle cavity. The hemolymph sinuses are oriented so that hemolymph flows in the opposite direction. Interstitial cells link epithelial cells with nerve endings. Muscle cells as well as the collagenous matrix in the connective tissue differ within the main gill axis and the lateral lamellae. The life cycle of immunoactive cells within the connective tissue and the hemolymph is described.
The digestive system of the fish ectoparasite Dolops ranarum (Crustacea: Branchiura)
Authors: Avenant‐Oldewage Annemarie , van As J. G. 
Published: February 2005

AbstractReconstructions from serial sections reveal that the digestive system consists of a pharynx esophagus, crop, midgut, and rectum. Two main stems from the branched enteral diverticula are connected to the lateral regions of the crop by right rind left arms. Glandular tissue surrounds the enteral diverticula proximally. A strong sphincter separates the crop and midgut, whereas the midgut and rectum are separated by a weak sphincter. Cuboidal epithelium lines the pharynx, esophagus, crop, and rectum, whereas cuboidal and club‐shaped epithelia line the midgut. The cuboidal cells possess elongated nuclei and numerous vacuoles, suggesting that absorption takes place in the midgut.
Differential scaling of the long bones in the terrestrial carnivora and other mammals
Authors: Bertram John E. A. , Biewener Andrew A. 
Published: February 2005

AbstractWe measured the lengths and diameters of four long bones from 118 terrestrial carnivoran species using museum specimens. Though intrafamilial regressions scaled linearly, nearly all intraordinal regressions scaled non‐linearly. The observed non‐linear scaling of bone dimensions within this order results from a systematic decrease in intrafamilial allometric slope with increasing body size. A change in limb posture (more upright in larger species) to maintain similar peak bone stresses may allow the nearly isometric scaling of skeletal dimensions observed in smaller sized mammals (below about 100 kg). However, strong positive allometry is consistently observed in a number of large terrestrial mammals (the largest Carnivora, the large Bovidae, and the Ceratomorpha). This suggests that the capacity to compensate for size increases through alteration of limb posture is limited in extremely large‐sized mammals, such that radical changes in bone shape are required to maintain similar levels of peak bone stress.
The relationship of pores and mammillae on the inner surface of the eggshell of the alligator (Alligator mississippiensis)
Authors: Wink Carole S. , Elsey Ruth M. , Bouvier Marianne 
Published: February 2005

AbstractThe morphology of the eggshell of the alligator, Alligator mississippiensis, is similar to that of birds. In many avian species there is a positive linear correlation between the numbers of pores and mammillae on the inner surfaces of eggshells, indicating that the distribution and density of mammillae may determine the porosity of the shell. It is not known, however, if a relationship exists between pores and mammillae on the shell of the alligator. Using a scanning electron microscope, we counted pores and mammillae on the inner surfaces of pieces of shell from the middle of fertile and infertile eggs from wild and captive, pen‐reared alligators. Data were analyzed by ANOVA, Duncan's multiple range tests and linear regression equations. Results demonstrate a positive linear correlation between the numbers of pores and mammillae on the shells of unincubated fertile and infertile eggs from wild and captive alligators; however, there is no correlation between pores and mammillae on shells of eggs that were incubated for 55 days. It is suggested that initially the porosity of the eggshell of the alligator is related to the density of mammillae on the inner surface of the shell and that erosion of the shell during incubation destroys the original relationship between pores and mammillae.
Histochemical and ultrastructural study of the digestive tract of the tortoise Testudo graeca (Testudines)
Authors: Perez‐Tomas R. , Ballesta J. , Madrid J. F. , Pastor L. M. , Hernandez F. 
Published: February 2005

AbstractThe digestive tract of the tortoise Testudo graeca (Testudines) was investigated by means of light and electron microscopy. The esophagus of T. graeca was lined by two types of epithelium: non‐keratinized stratified squamous in the upper portion and stratified columnar in the lower. The lamina propria of the esophagus contained tubular or tubuloacinar glands. The mucosa of the stomach showed similar characteristics to those of other reptiles. The small intestine exhibited longitudinal folds lined by absorptive and goblet cells. The large intestine was lined by columnar mucous cells. Within the lamina propria of the large intestine, masses of 10–15 epithelial cells connecting with the surface epithelium by means of slender cytoplasmic processes were observed. A battery of six lectins (Con‐A, PNA, WGA, DBA, SBA, and LTA) was used to identify the epithelial mucins. WGA and DBA reacted with all types of mucous cells throughout the alimentary canal. PNA was only unreactive in the intestine, LTA in the esophagus, and SBA in the large intestine. These results indicate a similar lectin‐binding pattern throughout the gut of T. graeca.
Ultrastructure of the blood vessels in the harderian gland of the hamster (mesocricetus auratus): Existence of sinusoids
Authors: Menendez‐Pelaez A. , Tolivia D. , Rodriguez‐Colunga M. J. , Reiter R. J. 
Published: February 2005

AbstractThe Harderian gland blood supply of female and male hamsters was studied using light and electron microscopy. A profuse vascularization surrounding secretory acini was observed. Among the blood vessels, the existence of large and irregular sinusoidal capillaries was apparent. These sinusoids appeared in close association to the basal aspect of the secretory cells. Typical, small, fenestrated capillaries were also observed within the connective tissue. The existence of this particular vascularization together with other morphological features of the secretory cell basal pole suggest a possible endocrine function of these orbital glands.
Histology and ultrastructure of the gut of the black mollie (poecilia spp.), a hybrid teleost
Authors: Caceci Thomas , Hrubec Terry C. 
Published: February 2005

AbstractA light and electron microscopic (TEM and SEM) study of the gut of the black mollie (Poecilia spp.) shows that the gut is a relatively undifferentiated muscular tube lined with a simple columnar epithelium. The mucosa and underlying lamina propria are formed into folds. The apices of the folds form obtuse angles at the cranial end and more acute ones caudally. The mucosal epithelium is a simple columnar sheet with PAS‐positive goblet cells interspersed throughout. The enterocytes are covered apically with uniform microvilli in most of the tract, and the plasma membrane deeply infolded basally. Mitochondria are located in the basal folds. A continuous basal lamina separates the epithelial mucosa from the underlying lamina propria. Enterocytes have a PAS‐positive Golgi apparatus in the supranuclear region. The enterocytes of the cranial and middle thirds of the gut are morphologically indistinguishable, but those in the caudal third display shorter and sparser microvilli. There is no evidence of pinocytotic activity in the enterocytes of the cranial two thirds of the gut tube, but some apical pinocytotic vesicles are seen in the cells in the caudal third. The tunica muscularis consists of two layers of smooth muscle, inner circular and outer longitudinal. We observe lateral separation of enterocytes from each other deep to the junctional complexes in the caudal and midgut regions. The gut of the mollie lacks some of the specialized cell types commonly found in other fishes. It cannot create an acidic gastric environment; overall control of digestive activity, osmolarity, and ionic balance presumably rest in the structural relationships between epithelial cells and between the epithelium and its supporting tissues. Regional specialization of cells and of the gut as a whole may confer digestive function equivalent to that found in more complicated systems.
Thymus of Rana perezi: Presence of interdigitating cells
Authors: Alvarez Rafael 
Published: February 2005

AbstractIn the thymus of Rana perezi, as in other anuran amphibians, there exist two different portions, cortex and medulla. In both sections epithelio‐reticular cells are observed as are lymphocytes, macrophages, and granulocytes. In addition, the medulla shows cysts and secretory, myoid, and hypertrophied epithelio‐reticular cells. In the cortex, plasma cells and interdigitating cells were also observed. Interdigitating cells make contact with lymphocytes. This finding provides morphological support for the hypothesized role of interdigitating cells in antigen presentation.
Morphological changes in the oviductal endometrium during the reproductive cycle of the tortoise,Gopherus polyphemus
Authors: Palmer Brent D. , Guillette Louis J. 
Published: February 2005

AbstractThe oviducts of 24 tortoises (Gopherus polyphemus) were examined using histological techniques and scanning electron microscopy to determine endometrial morphology. Measurements of endometrial characteristics (epithelial cell height, cilia length, thickness of endometrial glandular layer, and glandular diameter) in the uterus and tube (tuba uterina) were obtained to determine changes during the reproductive cycle. Epithelial cell height increases in both the uterus and the tube during vitellogenesis and remains hypertrophied during gravidity. Cilia length increases in the uterus during late vitellogenesis and gravidity, but the length of tubal cilia does not change during the reproductive cycle. The ratio of secretory to ciliated epithelial cells in the oviduct increases from quiescence to gravidity. The thickness of the glandular endometrial layer increases in both the uterus and tube during vitellogenesis. In the uterus, the glandular layer decreases in thickness during gravidity. The diameter of the uterine glands increases throughout vitellogenesis and gravidity; however, following ovulation glandular cells become depleted of secretory granules and cell height diminishes. The diameter of the tubal glands is unchanged during the reproductive cycle. Oviductal hypertrophy during vitellogenesis coincides with elevated circulating estradiol, whereas during gravidity progesterone concentrations peak (Taylor, '82, PhD Dissertation, University of Florida, Gainesville) and may induce secretion of albumen and eggshell components.
Interhemispheric connections through the pallial commissures in the brain of Podarcis hispanica and Gallotia stehlinii (Reptilia, Lacertidae)
Authors: Martíanez‐Garcíaa Fernando , Amiguet Miguel , Schwerdtfeger Walter K. , Olucha Francisco E. , Lorente María Joséa 
Published: February 2005

AbstractThe cells‐of‐origin and the mode and site of termination of the interhemispheric connections passing through the anterior and posterior pallial commissures in the telencephalon of two lizards (Podarcis hispanica and Gallotia stehlinii) were investigated by studying the anterograde and retrograde transport of unilaterally injected horseradish peroxidase. The commissural projections arise mainly from pyramidal cells in the medial, dorsomedial, and dorsal cortices (medial subfield). Additionally some non‐pyramidal neurons in the medial and dorsal cortices contribute to the commissural system. Medial cortex neurons project to the contralateral anterior septum through the anterior pallial commissure. The dorsomedial cortex projects contralaterally via the anterior pallial commissure to the dorsolateral septum and to the medial, dorsomedial, and dorsal cortices. The projection to the medial cortex terminates in two bands at the inner and outer border, respectively, of the cell layer; the projection to the dorsomedial and dorsal cortex ends in a zone in layer 1 which previously has been described to be Timm‐negative, and in a diffuse band in the inner half of layer 3. The medial subfield of the dorsal cortex projects through the anterior pallial commissure to the dorsomedial and dorsal cortices with a similar pattern of termination to that found for the dorsomedial cortex. The posterior pallial commissure contains only the projections from the ventral cortex to its contralateral counterpart and to the ventral part of the caudal medial cortex. The similarities found between this commissural system and the mammalian hippocampal interhemispheric connections are discussed.
Development of the extraembryonic membranes and histology of the placentae in Virginia striatula (Squamata: Serpentes)
Authors: Stewart James R. 
Published: February 2005

AbstractDevelopment of the extraembryonic membranes and their structural alignment in the formation of the four placental categories that occur in Virginia striatula is similar to that of other Serpentes. The vascularized trilaminar omphalopleure contacts the uterine epithelium early in development to form the choriovitelline placenta, which subsequently extends over the surface of the yolk to its limit at the margin of the isolated yolk mass. As in other squamates, the isolated yolk mass is separated from the yolk sac by the growth of intravitelline cells into the yolk. The bilaminar omphalopleure (ectoderm, endoderm) of the isolated yolk mass contributes the fetal epithelium of the omphaloplacenta. During formation of the omphidoplacenta, the allantois makes its initial contact with the chorion dorsal to the embryo. As the allantois expands, the chorioallantoic placenta gradually replaces the choriovitelline placenta. The terminal placental stage is defined by an extensive chorioallantoic placenta and an omphalallantoic placenta associated with the isolated yolk mass. Although similar in most aspects to the omphalallantoic placentae of other snakes, a secondary yolk cleft develops in V. striatula. This structure, which separates the outer allantoic membrane from the isolated yolk mass, has not been described in other squamates. The choriovitelline placenta and most of the surface of the chorioallantoic placenta are characterized by close vascular apposition, whereas the omphaloplacenta and omphalallantoic placenta feature uterine and fetal epithelial cell hypertrophy in the absence of fetal vascular support. A narrow zone within the chorioallantoic placenta, lying on either side of the omphalallantoic placenta, contains hypertrophied epithelial cells with supporting capillaries on both fetal and maternal aspects.