bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anatomical observations on the ending of the human thoracic duct
Authors: Zorzetto Neivo Luiz , Ripari Wagner , De Freitas Valdemar , Seullner Geraldo 
Published: February 2005

AbstractFifty‐one cadavers of human adults of both sexes were examined for the raminfications and site of opening of the cervical segment of the thoracic duct. It was found that the duct opened into veins of the neck through either one (84.31%) or two branches (15.69%). The most frequent site of opening was in the junction of the left internal jugular vein with the subclavian vein (18 individuals), but another frequent site (15 individuals) was in the internal jugular vein. The duct opened at the angle formed by the internal jugular vein and the internal posterior jugular vein in five individuals, and at a variety of the other locations in the remaining cadavers. These results are compared with the findings of previous investigators.
Microscopy of the junctional region between human coronal primary and secondary dentine
Authors: Scott John N. , Weber Dennis F. 
Published: February 2005

AbstractThe junction between human primary dentine and regular and irregular secondary dentine was examined with a number of different light and electron microscopic techniques. In decalcified material, a narrow band along the innermost surface of the primary dentine stained intensely. The walls of the tubules within the band stained intensely, whereas the tubular walls within the bulk of the primary dentine were not stained. Generally, the walls of the tubules in both types of secondary dentine were also preferentially stained. Although not readily apparent in ground sections, observations of thin sections revealed a dramatic reduction in the number of tubules in regular secondary dentine. Generally, the radiodensity of the intertubular matrix was the same in primary and secondary dentine and the intensely stained band was not seen radiographically. The pulpal ends of the tubules in primary dentine were often occluded with a material having the same radiodensity as peritubular matrix. Both patent and occluded tubules were seen in irregular secondary dentine. Scanning electron microscopy of acid‐etched specimens of secondary dentine revealed that some tubules had irregular walls of highly mineralized matrix which was less acid‐soluble than the peritubular matrix of primary dentine.
External morphology of Xyleborus ferrugineus (Fabr.) (Coleoptera: Scolytidae). I. Head and prothorax of adult males and females
Authors: Kingsolver Joel G. , Norris Dale M. 
Published: February 2005

AbstractThe overall body dimensions and external morphology of the head, head appendages, prothorax, and prothoracic legs of the adult haploid male and diploid female Xyleborus ferrugineus (Fabricius) were examined by scanning electron microscopy and light microscopy, and analyzed for variation. The female is significantly larger (1.26 X) than the male. The length/width ratio of both the pronotum and elytron, and the pronotum‐length/elytron‐length ratio are significantly different in the male and female. These findings indicate a distinct sexual dimorphism in general body form. There is significantly greater variability in pronotal length and width in the male than the female. There are sexual differences in setal patterns and setal size variabilities on the dorsal pronotum and the terminus of the antennae.
Development of dorsoventral polarity and mesentoblast determination in Patella vulgata
Authors: van den Biggelaar J. A. M. 
Published: February 2005

AbstractIn Patella vulgata the 32‐cell stage represents a pause in the mitotic activity prior to the differentiation of the mesentoblast mother cell 3D. At the onset of this stage, the embryo is radially symmetrical. Nevertheless, the plane of bilateral symmetry is indicated as it passes through the macromeres forming the vegetal cross‐furrow. From the early beginning of the 32‐cell stage, all four macromeres intrude far into the interior and touch the centrally radiating cells of the first quartet of micromeres. The two cross‐furrow forming macromeres (3B and 3D) intrude the farthest and come into contact with the greatest number of micromeres. Finally, the contacts are extended significantly and maintained with only one of these macromeres. From that moment, this cell can be called the macromere 3D and the dorsoventral axis is determined. The evolution of the internal cell contacts between the micromeres of the first quartet and the macromeres indicates an essential role of the former in the determination of one of the latter as the mesentoblast mother cell, and thus in the determination of dorsoventral polarity.
Ultrastructure of the acinar cells in the submandibular gland of the nine‐banded armadillo
Authors: Ruby John R. , Canning Harold B. 
Published: February 2005

AbstractThere are two discrete lobes comprising the armadillo subman‐dibular gland. These two lobes can be defined grossly, histochemically and morphologically with the light and electron microscope. The minor lobe stains more intensely with PAS and AB. When viewed in the electron microscope, the secretory granules of the acinar cells within this lobe appear mucous‐like. The granules of the demilune cells are slightly different in appearance. The secretory granules of the acinar cells in the major lobe contain many dense foci embedded in a fibrillar matrix, a substructure not described previously. The demilune cells of this lobe contain secretory granules with a mucous‐like structure which is consistent throughout the entire lobe. As in the minor lobe, these demilune cells stain very intensely with PAS and AB.
The preglossale of Passer (Aves: Passeriformes) ‐ a skeletal neomorph
Authors: Bock Walter J. , Morony John 
Published: February 2005

AbstractA skeletal neomorph – the preglossale – is described from the tip of the tongue in Passer. This medial unpaired skeletal element is a dorsally open trough articulating with the anterior tips of the paraglossalia and supporting the heavy epidermal pad of the seed‐cup. The large paired Mm. hypoglossus anterior originate from the posterior half of the preglossale and insert onto the anterior bodies of the paired paraglossalia; they serve to depress the anterior portion of the preglossale. A regular pattern of dermal papillae is present in the seed‐cup; these are arranged in about 20 rows of six to 8 papillae per row. Each papilla contains a series of Merkel cells and associated nerve endings (touch receptors). The seed‐cup serves to orient and hold the seed in place while it is being husked; the battery of tactile receptors provides information on the position of the seed on the tongue. The preglossale serves to support the seed‐cup and to change its shape – the curvature of the dorsal surface – as it is depressed relative to the paraglossalia. The paraglossale and associated features of the seed‐cup in Passer would provide a valuable preparation to study a diversity of problems such as developmental interactions between endomesodermal and ecto‐mesenchymal skeletal features, the ontogenetical development of Merkel cells, and the sensory physiology of Merkel cells and their associated nerve endings as tactile corpuscles.
Insertions and functions of certain flexor muscles in the hind leg of rodents
Authors: Hildebrand Milton 
Published: February 2005

AbstractThis survey includes 58 genera of rodents from 26 families. The medial tarsal bone is probably unique to the order. Its presence, nature, and constant relationship with M. tibialis posterior are discussed. This muscle inverts and supinates the pes at the astragulo‐navicular joint and moves the ankle.The M. flexor tibialis inserts on the medial sesamoid, on this sesamoid and the integument, on the sesamoid and the tendon of M. flexor fibularis, on the latter tendon only, or on the integument only. The occurrence, nature, and cam‐like action of the sesamoid are described. A distal segment of the tendon of M. flexor tibialis usually extends from the sesamoid to either the first phalanx of the first digit or to fascia of an adjacent muscle.Functions of the medial sesamoid include (1) stabilization of the tendon of M. flexor tibialis, (2) deflection of this tendon to benefit flexion of the first phalanx, (3) winching of the medial tarsal ligament to flex the first metatarsal, (4) control of the angle of insertion of the tendon to provide flexion or abduction of the first digit as appropriate during swimming, (5) mechanical multiplication of the tension in the tendon between the segments proximal and distal to the sesamoid, and (6) longitudinal folding of the sole of the pes to grip the substrate, as in climbing.
Cell renewal in the epithelium of the alimentary tract of the larval lamprey, Petromyzon marinus L.
Authors: Hansen Susan J. , Youson John H. 
Published: February 2005

AbstractLight microscopic autoradiography with 3H‐thymidine demonstrates that the three regions of the alimentary tract in the larval (ammocoete) lamprey, Petromyzon marinus L., possess different patterns for renewing their epithelium. In the oesophagus, columnar and mucous cells originate from stem cells located at the bases of folds and migrate to the tops of the folds where they are apparently extruded. Ciliated cells, located only at the tops of the folds, seem to differentiate from migrating columnar cells. In the anterior intestine, stem cells are present throughout the epithelium so that there is limited migration of cells and their extrusion occurs randomly. In the posterior intestine, the stem cells located at the bases of the typhlosole provide a continuous population that differentiates and migrates to the top of the typhlosole and to the opposite epithelial wall where they are presumably extruded. The rates of cell renewal in all three epithelial regions of the alimentary tract are slower in animals maintained at 10 ± 1°C compared with those kept at 21 ± 1°C. Comparatively, ammocoetes have the least specialized system for cell renewal known in the alimentary tract of a vertebrate.
The cat step cycle: Electromyographic patterns for hindlimb muscles during posture and unrestrained locomotion
Authors: Rasmussen S. , Chan A. K. , Goslow G. E. 
Published: February 2005

AbstractThe telemetered electromyographic activity (EMG) of select hindlimb muscles of unrestrained cats during standing, walking, trotting, and galloping have been recorded. Simultaneous cinematographic records permitted close correlation of muscle activity and locomotor behavior. In general, the pattern of extensor activity of the ankle, knee, and hip during locomotion is fairly consistent, while that of the flexors is more variable.Changes in basic EMG patterns from walk, to trot, to gallop are most evident in the two‐jointed muscles associated with the knee and hip. Progressively greater variation of activity onset and cessation can be seen among extensor muscle groups from the walk, to trot, to gallop. Co‐activation of the joint extensors and flexors, especially of the hip, at the end of the stance phase (E3) is slight in the walk, moderate in the trot, and considerable in the gallop. These EMG changes are necessary to meet the demands imposed upon the musculature at the faster gaits, particularly galloping, which include limb rigidity as related to loading, momentum as related to the limb's directional change from the stance phase to the swing phase, and lower spinal movements.The peroneal muscles of the ankle and the gluteal muscles of the hip show extensor activity and act as joint stabilizers during locomotion. Both biceps femoris anterior muscle and biceps femoris posterior muscle show consistent hip extensor patterns at all gaits. During quiet standing, extensor activity about the knee, ankle, and metatarsophalangeal joints is evident; but the hip extensor and flexor musculature is remarkably silent.EMG data for unrestrained cats are compared to those of dogs on a treadmill (Tokuriki, '73a,b, '74; Wentink, '76) and those recorded from decerebrate cats (mesencephalic preparation) during controlled locomotion (Gambaryan et al., '71). The EMG patterns from decerebrate cats are more consistent at the walk and gallop within functional groups of muscles at the ankle, knee, and hip than the EMG patterns observed in unrestrained cats or animals moving on a treadmill.
Studies on the renal sac of the ascidian Molgula manhattensis. I. Development of the renal sac
Authors: Saffo Mary Beth 
Published: February 2005

AbstractThe renal sac of the ascidian family Molgulidae (Tunicata, phylum Chordata) has been thought to function as a kidney, yet its structure, contents and activities seem incompatible with current generalizations regarding excretory processes in marine animals. The development of the renal sac is described here as part of a general effort to reexamine the organ's role in Molgula manhattensis. Light microscopy of living animals and fixed material has shown the following: (1) The renal sac begins to sequester concretions before the heart starts beating and before feeding begins. Therefore, blood circulation by heartbeat is not necessary for production or transport of the initial concretions, whatever its effects may be on the renal sac in older individuals. Ingested food cannot provide the initial concretion material. (2) In laboratory‐raised animals, concretions appear in the renal sac before “renal sac organisms” (fungus‐like organisms seen in the renal sac of all field‐collected adults) can be detected. Thus, at least some portion of the concretions can be produced by Molgula in the absence of renal sac organisms. (3) No openings have been detected in the renal sac at any stage of its development, nor is there any evidence that concretions are dissolved or transported out of the renal sac. (4) The development and morphology of the renal sac are consistent with the hypothesis that the organ is an epicardial derivative, except that the renal sac arises from post‐pharyngeal (presumptive gut) endoderm, rather than pharyngeal endoderm.
The ultrastructure of the metathoracic femoral extensors of the cockroach, Periplaneta americana
Authors: Fourtner Charles R. 
Published: February 2005

AbstractThe ultrastructure of the femoral extensors of the metathoracic leg of the cockroach, Periplaneta americana was studied to determine morphological correlations with the known patterns of innervation, physiological properties and biochemical properties. Three different types of muscle fibers were described. Type 1 consisted of short sarcomeres (mean 3.7 μm), few mitochondria and sparse glycogen‐like material; Type 2, short sarcomeres (4.2 μm), numerous mitochondria, large amounts of glycogen; Type 3, long sarcomeres (7.5 μm), numerous mitochondria and large amounts of glycogen. A qualitative examination of the sarcoplasmic reticulum (SR) and transverse tubular system (TTS) revealed the density of SR and TTS to be greatest in Type 1 and least in Type 3. There were obvious correlations between the morphological features and the other known characteristics of these muscle fibers. The role of these different muscle fiber types in different locomotory behaviors was discussed. In summary, the three types of muscle fibers are used in three different behaviors: Type 1, rapid walking; Type 2, slow walking; Type 3, postural control.
Functional analysis of the shoulder girdle of cats during locomotion
Authors: English Arthur William 
Published: February 2005

AbstractThe movements of the shoulder girdle of eight adult cats during overground stepping were studied, using standard slow motion cinematographic techniques. The patterns of activity of shoulder muscles were examined, using simultaneous intramuscular electromyography. Walking, trotting and galloping steps were analyzed from digitized single motion picture frame images. Angular movements of the shoulder girdle consist of biphasic flexion and extension of the shoulder joint and a monophasic flexion‐extension alternation of the scapula on the thorax during each step cycle. In addition, the center of the scapula moves craniad during the swing phase and caudad during the stance phase with respect to a fixed reference point on the animal. Similar vertical movements of the center of the scapula also occur in each step cycle. Results of EMG studies of the 17 muscles capable of acting on the shoulder girdle indicate that three overall patterns of activity are found: (1) a pattern typical of extensor muscles, active during all the extension epochs; (2) a pattern typical of flexor muscles, active during the flexion epoch; and (3) a biphasic pattern of activity, active twice in each step. These data are used, along with a re‐examination of previous models of the mechanics of the shoulder girdle of carnivores to examine the function and mechanics of shoulder motion. It is concluded that the rotary and translatory movements of the shoulder girdle during stepping combine to enhance step length.
Ultrastructural studies on the formation of yolk granules in the statoblast of a fresh‐water bryozoan, Pectinatella gelatinosa
Authors: Terakado Kiyoshi , Mukai Hideo 
Published: February 2005

AbstractThe formation of protein‐carbohydrate yolk in the statoblast of a fresh‐water bryozoan, Pectinatella gelatinosa, was studied by electron microscopy. Two types (I and II) of yolk cells were distinguished. The type I yolk cells are mononucleate and comprise a large majority of the yolk cells. The type II yolk cells are small in number; they become multinucleate by fusion of cells at an early stage of vitellogenesis. In both types of yolk cells, electron‐dense granules (dense bodies) are formed in Golgi or condensing vacuoles, which are then called yolk granules. For the formation of yolk granules, the following processes are considered: 1. Yolk protein is synthesized in the rough‐surfaced endoplasmic reticulum (RER) of the yolk cells. 2. The synthesized protein condenses in the cisternal space of the RER and is packaged into small oval swellings, which are then released from the RER as small vesicles (Golgi vesicles, 300‐600 A in diameter). 3. The small vesicles fuse with one another to form condensing vacuoles, or with pre‐existing growing yolk granules. 4. In the matrix of the condensing vacuoles or growing yolk granules, electron‐dense fibers are fabricated and then arranged in a paracrystalline pattern to form the dense body. 5. After the dense body reaches its full size, excess membrane is removed and eventually the yolk granules come to mature. Toward the end of vitellogenesis of the yolk cells, the cytoplasmic organelles are ingested by autophagosomes derived from multivesicular bodies and disappear.
Early events in sea urchin metamorphosis, description and analysis
Authors: Cameron R. Andrew , Hinegardner R. T. 
Published: February 2005

AbstractThe larval epithelium of the sea urchin, Lytechinus pictus, consists of squamous cells and bands of columnar epithelial cells bearing cilia. During metamorphosis this tissue undergoes a series of rapid, complex changes. Through the scanning and transmission electron microscope, we describe and analyse these changes. The changes can be divided into three steps. (1) The larval arms bend away from the left side of the larva, exposing the urchin rudiment. Cells which are identical to smooth muscle cells are in a position to bring about this bending. (2) The squamous epithelial cells assume a cuboidal shape. This change in shape results in the collapse of the larval epithelium onto the presumptive aboral surface. These cells possess a subapical band of microfilaments. The cellular shape change but not the bending of the arms is reversibly inhibited by Cytochalasin B. These observations suggest a mechanism for this change. (3) The former lining of the vestibule of the urchin rudiment comes to lie over the collapsed larval tissue and forms the adult epithelium. At this point, after only one hour, the larva has assumed the external shape of an adult sea urchin.
Histological and ultrastructural specialization of the digestive tract of the intestinal air breather hoplosternum thoracatum (teleost)
Authors: Huebner Erwin , Chee Ghan 
Published: February 2005

AbstractThe digestive tract of Hoplosternum thoracatum consists of an esophagus, gastric area, anterior digestive intestine with elaborate folds, digestive intestine with decreasing folds and thin, smooth‐surfaced respiratory intestine. The upper tract has a mucoid columnar lining which is gently folded, whereas the gastric area has numerous pits opening into the tubular secretory glands. Striated muscle comprises the anterior muscularis but is replaced by inner circular and outer longitudinal smooth muscle layers in the gastric region. The digestive intestinal mucosa is elaborately folded, consisting of columnar cells with prominent brush borders. Mucosa, submucosa, circular and longitudinal muscularis and serosa layers are present throughout the tract. Goblet cells occur in both the digestive and respiratory intestine. Major changes that appear in the respiratory intestine are a drastic reduction in mucosa epithelial thickness and the penetration of an elaborate capillary bed into the epithelium. The other basic layers are not significantly reduced in thickness. The air‐blood barrier consists of the thin epithelium, basement lamina and very thin capillary endothelium. Regional cellular composition and ultrastructural features are correlated with respective digestive and respiratory functions.
The anatomy of the forelimb in the anteater (Tamandua) and its functional implications
Authors: Taylor Bruce K. 
Published: February 2005

AbstractThe forelimbs of anteaters play a major role in obtainment of food, defense, and locomotion. The greatly enlarged claws on the manus are used for ripping open insect nests and insect‐infested wood; the claws also serve as the animals' only defensive weapons, since they lack teeth. Specialization of the claws for these functions has also had a substantial effect on the ways in which the forelimb is used for posture and locomotion.Modifications of the forelimb in the anteater Tamandua include the following. Attachments of the medial head of triceps are rearranged so as to greatly increase capability for powerful flexion of the claws. Ability to flex the elbow and to retract the humerus is also augmented; these movements would assist digital flexion in applying traction with the claws to material being torn away during food procurement. This traction can be supplemented by a variety of powerful side‐to‐side and/or twisting movements of the hand, brought about primarily by axial rotation of the upper arm and forearm. The digital joints are reinforced to resist the deviational and torsional loading to which the digits would be subjected during such movements.The morphological modifications of the forelimb in Tamandua are discussed in terms of how they affect the mechanical capabilities of the limb, what functions the limb is best designed to perform, how they may relate to what little is known about the specialized behavior of this animal, and what behavioral predictions may be made based on mechanical design.