The Structure of the Unpaired Ventral Nerves in the Blowfly Larva

1964 ◽  
Vol s3-105 (71) ◽  
pp. 325-329
Author(s):  
M. P. OSBORNE
Keyword(s):  
Schwann Cells ◽  
Dorsal Surface ◽  
Lateral Nerve ◽  
Nerve Branch ◽  
Tracheal System ◽  
Electron Microscopical ◽  
Connective Tissue Sheath ◽  
Cytoplasmic Processes ◽  
Longitudinal Muscles ◽  
Transverse Muscle

The anatomy and histology of the unpaired ventral nerves are described from light-and electron-microscopical studies. Seven unpaired nerves arise from the median dorsal surface of the ventral ganglionic nerve-mass, and terminate in abdominal segments 2 to 8 respectively. Each unpaired nerve bifurcates, sending a lateral nerve to both sides of its respective segment. Subsequently the lateral nerve gives rise to 2 nerve-branches. The first branch runs to a multipolar neurone that is associated with the tracheal system, and the second branch passes beneath the ventral longitudinal muscles and terminates on a ventral transverse muscle. Structurally, the unpaired nerve consists of axons ensheathed by Schwann-cells, the cytoplasmic processes of 2 giant Schwann-cells forming the entire neurilemma sheath of the nerve and its branches. A basement membrane, or connective-tissue sheath, about 2 µ thick surrounds the Schwann-cells. Four nerve-fibres are found in the unpaired nerve; 2 of these bifurcate, sending a fibre into both lateral nerves, but the other 2 fibres pass without dividing, into the left and right lateral nerves respectively, making a total of 3 fibres in both lateral nerves. One fibre from the lateral nerve enters the nerve-branch leading to the multipolar neurone associated with the tracheal system, and eventually joins its cell-body. This fibre is the axon of the neurone. The remaining 2 fibres in the lateral nerve pass into the nerve-branch that runs to the ventral transverse muscle. A comparison is made between the unpaired nerves of the blowfly larva and those in other insects.

THE GROSS AND MICROSCOPIC ANATOMY OF THE DIGESTIVE TRACT OF THE OYSTER CRASSOSTREA VIRGINICA (GMELIN)

1957 ◽  
Vol 35 (3) ◽  
pp. 325-347 ◽  
Author(s):  
Barbara L. Shaw ◽  
Helen I. Battle
Keyword(s):  
Epithelial Cells ◽  
Digestive Tract ◽  
Crassostrea Virginica ◽  
Atlantic Coast ◽  
Dorsal Surface ◽  
Adductor Muscle ◽  
Posterior Chamber ◽  
Microscopic Anatomy ◽  
The North ◽  
Cytoplasmic Processes

The gross and microscopic anatomy of the digestive tract of Crassostrea virginica (Gmelin), the common oyster of commerce of the North Atlantic Coast, is described. The dorsoventrally compressed mouth bounded by two pairs of labial palps leads into a crescentic oesophagus, thence to the anterior chamber of the stomach from which a complex caecum extends into anteriorly and posteriorly directed spiral appendices. The posterior chamber of the stomach bears a chondroid gastric shield and leads into an elongated chamber which is incompletely divided by two typhlosoles into a style-sac and mid-gut. The intestine is divisible into ascending, median, and descending limbs, the latter merging into the rectum which terminates on the dorsal surface of the adductor muscle. Extensively branched tubular digestive diverticula exit from the stomach by a series of ducts along the margin of the caecum and the posterior stomach. The complete digestive tract is lined by a simple columnar epithelium which is ciliated throughout with the exception of the upper lip or fused external palps, the lower side of the gastric shield in the posterior stomach, and the tubules of the digestive diverticula. Mucous secreting and eosinophilic epithelial cells occur in varying numbers along the course of the tract. Phagocytes are present between the lining epithelial cells, among the peripheral collagenous and muscle fibers, as well as in the lumen of the tract. The gastric shield is shown to be intimately attached to the underlying epithelium by a central clip as well as by minute cytoplasmic processes. The anatomical relationships are compared with various lamellibranchs including the Chilean oyster, Ostrea chilensis Philippi; the European oyster, Ostrea edulis L.; and the Portuguese oyster, Gryphea angulata Lamarck.

Memoirs: The Loxosomatidae of the Plymouth Area, including L. obesum sp. nov

1932 ◽  
Vol s2-75 (298) ◽  
pp. 321-391
Author(s):  
DAPHNE ATKINS
Keyword(s):  
New Species ◽  
Small Group ◽  
Average Length ◽  
Dorsal Surface ◽  
Valid Species ◽  
Sense Organs ◽  
Small Disc ◽  
Longitudinal Muscles ◽  
Sexually Mature ◽  
A New Species

Four known species of Loxosoma, namely, L. phascolosomatum Vogt, L. crassicauda Salensky, L. singulare Keferstein, and L. claviforme Hincks, and a new species L. obesum are found in the Plymouth region, and are described. L. phascolosomatum is found on Phascolosoma vulgare, and in addition on two molluscs, Lepton clarkiae and Mysella bidentata from the burrows of Phascolosoma (pellucidum) elongatum from the Salcombe Estuary. L. crassicauda lives in the tanks in the Laboratory. Its average length is 1.4 mm. Between March 1929 and February 1930 males only were found: no ova were seen. L. singulare.--Occurs on Aphrodite aculeata; it varies between 0.18 and 0.8 mm. in length. In females carrying embryos the vestibule has two diverticula, one on either side of the rectum. L. claviforme.--It is considered a valid species, and may be distinguished from L. singulare by: (1) its greater size and length of stalk, (2) greater number of tentacles (commonly twelve), (3) position of the budding zone, and (4) the presence of paired sense-organs. Its average length is about 0.8 mm. It occurs on Hermione hystrix. A small group of Loxosoma, found on Aphrodite aculeata, were intermediate in form between L. singulare and L. claviforme, and were peculiar in retaining a number of their buds. The sex of such buds in several instances differed from that of the parent. L. obesum sp. nov. is found on the dorsal surface of Aphrodite aculeata. It may reach a length of 2.4 mm.; average individuals are rather more than 1.0 mm. in length. The lophophore is small, and bears almost invariably eight tentacles. Longitudinal muscles only are present in the stalk, which ends in a small disc of attachment. A foot-gland is present in the bud, and is frequently preserved as a vestige in the adult. The buds are near the lophophore, and may be as many as six on either side. The larva resembles that of L. singulare. Two main forms may be distinguished, differing in shape of the calyx and development of the stomach. The ovary may contain six well-developed ova on either side, and the vestibule twenty-six embryos. With one exception, females greatly exceeded males in number, and it is probable that the male becomes sexually mature at a smaller size than does the female.

Anatomico-Clinical, Histologic and Ultrastructural Features of Neurofibromatosis of the Bladder

1968 ◽  
Vol 54 (3) ◽  
pp. 237-253
Author(s):  
Natale Pennelli ◽  
Ignazio Stoppelli
Keyword(s):  
Schwann Cell ◽  
Schwann Cells ◽  
Intercellular Substance ◽  
Principal Cells ◽  
Basement Lamina ◽  
Unmyelinated Nerve ◽  
Cytoplasmic Processes

Anatomico-clinical, histologic and ultrastructural data of a case of neurofibromatosis of the bladder are reported. The principal cells of the neurofibroma appear isolated in the intercellular substance and have thin cytoplasmic processes, vacuoles, microfibrils, dense osmiophilic bodies and occasional ergastoplasmic tubules. Moreover, the presence of intracytoplasmic axons, a basement lamina of thickened amorphous periplasmalemmatic material and cilia support the theory of the Schwann cell origin of these cells. On the basis of these observations, the hypothesis that neurofibroma, in contrast to neurinoma, arises from the Schwann cells of unmyelinated nerve is advanced.

scholarly journals The Ultrastructure of Bovine Peripheral Nerve Sheath Tumours

1978 ◽  
Vol 15 (3) ◽  
pp. 292-300 ◽  
Author(s):  
P. Canfield
Keyword(s):  
Peripheral Nerve ◽  
Schwann Cells ◽  
Extracellular Material ◽  
Cell Nuclei ◽  
Principal Cells ◽  
Nerve Sheath ◽  
Cytoplasmic Processes ◽  
Antoni Type ◽  
Perineurial Cells ◽  
Electron Lucent

Bovine peripheral nerve sheath tumours from 30 cattle were similar ultrastructurally to human schwannomas and neurofibromas. Bovine neurofibromatous tissue had large amounts of extracellular material, primarily collagen and electron lucent granular material. The principal cells had basal laminae and a disorganized proliferation of the plasmalemma. Axons were consistently seen and were surrounded by the plasmalemma of principal cells. The principal cells seemed to be Schwann cells or variants of them. Bovine schwannomas had areas similar to Antoni type A tissue with sparse extracellular material, few, if any, axons, and an apparent organized layering of cytoplasmic processes clad in a basal lamina. Cell nuclei often formed palisades. The principal cells in bovine schwannomas might be derived either from Schwann cells or perineurial cells. Bovine schwannomas appeared together with bovine neurofibromatous tissue in affected nerves.

scholarly journals The Spatiotemporal Analysis of Odorants at the Level of the Olfactory Receptor Sheet

1966 ◽  
Vol 50 (1) ◽  
pp. 25-41 ◽  
Author(s):  
Maxwell Mark Mozell
Keyword(s):  
Flow Direction ◽  
Spatiotemporal Analysis ◽  
Olfactory Nerve ◽  
Time Interval ◽  
Lateral Nerve ◽  
Gas Chromatograph ◽  
Nerve Branch ◽  
Relative Response ◽  
The Difference ◽  
Medial Nerve

Activity in two separate regions of the frog olfactory mucosa was sampled by simultaneously recording the summated neural discharges from the olfactory nerve branches originating from them. The difference in the activity from these two regions in response to a stimulus was measured by: (a) the ratio of the response amplitude recorded from the lateral nerve branch to that recorded from the medial nerve branch (LB/MB ratio), (b) the latency difference (or time interval) between these two responses. Equal concentrations of four different odorants were drawn into the nose by an artificially produced sniff of known dimensions. At each concentration in every animal the four chemicals were ranked in order of the magnitudes of their LB/MB ratios and again in order of their latency differences. Regardless of their concentration, the same chemicals fell into the same ranks in different animals. In addition, for each chemical the magnitudes of the ratios and latency differences showed only minimal changes with concentration. Thus, spatiotemporal patterns of relative response magnitudes and latency differences across the mucosa differentially represented the odorants. Such a spatiotemporal code, together with physicochemical considerations, suggested that the nose separates vapors in a manner similar to a gas chromatograph. This is further supported by the previously observed reversal of the ratio patterns with reversal of air flow direction through the olfactory sac.

Morphological Comparison between Neonatal and Adult Human Tongues

2003 ◽  
Vol 112 (9) ◽  
pp. 768-776 ◽  
Author(s):  
Andrew Iskander ◽  
Ira Sanders
Keyword(s):  
Longitudinal Muscle ◽  
Dorsal Surface ◽  
Muscle Group ◽  
Dimensional Model ◽  
Morphological Comparison ◽  
3 Dimensional ◽  
Adult Human ◽  
Human Tongue ◽  
Morphological Differences ◽  
Transverse Muscle

There are currently no descriptions of neonatal tongue anatomy. Therefore, there have been no reports on the morphological differences between it and the adult tongue that would suggest its suitability for suckling. Serial coronal sections of a neonatal tongue were used to create a 3-dimensional model that was compared to that of the adult tongue. Compared to the adult human tongue, the neonatal tongue was found to contain 1) considerably less fat and soft tissue; 2) a thinner mucosa; 3) relatively enlarged extrinsic musculature; 4) a less-developed superior longitudinal muscle, resulting in a flat dorsal surface; and 5) attachments between the extrinsic muscles and the transverse muscle group that have not been identified in the adult tongue. The particular structure of the neonatal tongue suggests how the neonatal tongue is specialized for suckling.

Scanning electron microscopical studies on the tegument of adult worms of Schistosoma mansoni originating from ultraviolet-irradiated and non-irradiated cercariae

1999 ◽  
Vol 73 (2) ◽  
pp. 157-161 ◽  
Author(s):  
S.H. Mohamed
Keyword(s):  
Schistosoma Mansoni ◽  
Surface Topography ◽  
Dorsal Surface ◽  
Ultrastructural Changes ◽  
Electron Microscopical ◽  
Scanning Electron

The surface topography and ultrastructural changes ofSchistosoma mansoniworms developed from ultraviolet-irradiated cercariae were compared with those from non-irradiated cercariae. The tegument of worms developed from irradiated cercariae showed a variety of changes including the occurrence of oedemata and most of the tubercles being torn at the tip and having lost their spines on the dorsal surface of some male worms. In females, parts of the tegument were devoid of spines and surface lesions were present. The range and extent of these changes differed not only among individual worms but also between different regions of individual worms resulting in generalized deformities in those worms originating from irradiated cercariae.

scholarly journals The pruned gene encodes the Drosophila serum response factor and regulates cytoplasmic outgrowth during terminal branching of the tracheal system

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1353-1362 ◽  
Author(s):  
K. Guillemin ◽  
J. Groppe ◽  
K. Ducker ◽  
R. Treisman ◽  
E. Hafen ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Ternary Complex ◽  
Serum Response Factor ◽  
Response Factor ◽  
Loss Of Function ◽  
Tracheal System ◽  
Expression Of Genes ◽  
Serum Response ◽  
Cytoplasmic Processes ◽  
Ternary Complex Factor

We identified a Drosophila gene, pruned, that regulates formation of the terminal branches of the tracheal (respiratory) system. These branches arise by extension of long cytoplasmic processes from terminal tracheal cells towards oxygen-starved tissues, followed by formation of a lumen within the processes. The pruned gene is expressed in terminal cells throughout the period of terminal branching. pruned encodes the Drosophila homologue of serum response factor (SRF), which functions with an ETS domain ternary complex factor as a growth-factor-activated transcription complex in mammalian cells. In pruned loss of function mutants, terminal cells fail to extend cytoplasmic projections. A constitutively activated SRF drives formation of extra projections that grow out in an unregulated fashion. An activated ternary complex factor has a similar effect. We propose that the Drosophila SRF functions like mammalian SRF in an inducible transcription complex, and that activation of this complex by signals from target tissues induces expression of genes involved in cytoplasmic outgrowth.

Locomotion of the cercaria of Parorchis acanthus, Nicoll and the ultrastructure of the tail

Parasitology ◽  
1971 ◽  
Vol 62 (3) ◽  
pp. 489-503 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Electron Micrographs ◽  
Technical Assistance ◽  
Dorsal Surface ◽  
Cyst Formation ◽  
The Body ◽  
Parorchis Acanthus ◽  
Tail Tip ◽  
Longitudinal Muscles ◽  
Vesicular Secretion

The cercaria of Parorchis acanthus swims by a series of spasmodic ventral flexions of the body moving with the dorsal surface of the body foremost. The wave of contraction continues along the tail which therefore moves dorso-ventrally. Creeping movements precede cyst formation. The structure of the tail is admirably suited to swimming movements and to rapid shortening and lengthening. The wall is provided with circular and longitudinal muscles and abundant mitochondria. The centre of the tail contains fluid in which is a network of large myoblasts the processes of which overlap and probably slide over one another during the tail movements. Glands opening into the terminal tail invagination secrete an adhesive substance consisting of mucoprotein and glycoprotein which together with the vesicular secretion around the aperture enables the tail tip to attach itself to the substratum.I would like to express my sincere thanks to Dr I. ap Gwynn of this department for invaluable help in the preparation of the electron-micrographs and Mr R. A. Moore and Mr M. C. Bibby for technical assistance.

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