The Cuticle of Peripatopsis Moseleyi

1964 ◽  
Vol s3-105 (71) ◽  
pp. 281-299
Author(s):  
ELAINE A. ROBSON
Keyword(s):  
Body Wall ◽  
Light And Electron Microscopy ◽  
Thick Layer ◽  
The Body ◽  
Muscle Fibres ◽  
Terrestrial Arthropods ◽  
Dermal Glands ◽  
Arthropod Cuticle ◽  
Primitive Condition ◽  
Pore Canals

The integument of Peripatopsis moseleyi has been examined by light and electron microscopy with particular reference to the structure and formation of the cuticle. The evidence supports the idea that Peripatus is a true arthropod but not that it has direct affinities with the annelids. The characteristics of arthropod cuticle are present in their simplest form and pore canals and dermal glands are lacking. The cuticle is 1 or 2 µ, thick except in the hardened claws and spines. Above the procuticle (chitinprotein) is a thin 4-layered epicuticle. It is possible that the innermost of the 4 layers (prosclerotin) may correspond to cuticulin of other arthropods. In the claws and spines tanning in this layer extends to the procuticle. Hydrofuge properties of the cuticle probably depend on the outer layers of epicuticle, and it is suggested that the lamina concerned might consist of oriented lipid associated with lipoprotein (Dr. J. W. L. Beament). Wax and cement are absent. Non-wettability of the cuticle is probably ensured by the contours of micropapillae which cover the surface. Similar structures arise in Collembola and other terrestrial arthropods by convergence. The formation of new cuticle before ecdysis is described. After the epicuticular layers are complete, the bulk of the procuticle is laid down in a manner probably common to all arthropods. Secreted materials originate in small vesicles derived from rough endoplasmic reticulum and from scattered Golgi regions. The latter contribute to larger vacuoles which rise to the surface of the cell and liberate material in a fluid state. This later consolidates to form procuticle. Vesicles may also open to the surface directly, and ribosomes probably occur free in the cytoplasm. At this stage the cell surface is reticulate, especially under micropapillae. The ordinary epidermis has only one kind of cell, attached to the cuticle by tonofibrils disposed like the ribs of a shuttlecock, and to the fibrous sheaths of underlying muscle-fibres by special fibres of connective tissue. These features and the presence of numerous sensory papillae are associated with the characteristic mobility of the body wall. The appearance of epidermal pigment granules, mitochondria, the nuclear membrane, and a centriole are noted. No other cells immediately concerned in the formation of cuticle have been found. By contrast myriapods, which do not have wax either, possess dermal glands secreting far more lipid than is found in the Onychophora. The wax layer found in insects and some arachnids constitutes an advance of high selective value which emphasizes the primitive condition of the Onychophora. It is noted that the thick layer of collagen separating the haemocoel from the epidermis probably restricts the transfer of materials. It is suggested that since some features of cuticular structure and formation appear to be common to all arthropods, it is possible that some of the endocrine mechanisms associated with ecdysis may also be similar throughout the phylum.

Gross anatomy of the muscle systems and associated innervation of Apatemon cobitidis proterorhini metacercaria (Trematoda: Strigeidea), as visualized by confocal microscopy

Parasitology ◽  
2003 ◽  
Vol 126 (3) ◽  
pp. 273-282 ◽  
Author(s):  
M. T. STEWART ◽  
A. MOUSLEY ◽  
B. KOUBKOVÁ ◽  
š. šEBELOVÁ ◽  
N. J. MARKS ◽  
...  
Keyword(s):  
Nervous System ◽  
Oral Sucker ◽  
Body Wall ◽  
Circular Muscle ◽  
Gross Anatomy ◽  
The Body ◽  
Muscle Fibres ◽  
Filamentous Actin ◽  
Attachment Structures ◽  
A Site

The major muscle systems of the metacercaria of the strigeid trematode, Apatemon cobitidis proterorhini have been examined using phalloidin as a site-specific probe for filamentous actin. Regional differences were evident in the organization of the body wall musculature of the forebody and hindbody, the former comprising outer circular, intermediate longitudinal and inner diagonal fibres, the latter having the inner diagonal fibres replaced with an extra layer of more widely spaced circular muscle. Three orientations of muscle fibres (equatorial, meridional, radial) were discernible in the oral sucker, acetabulum and paired lappets. Large longitudinal extensor and flexor muscles project into the hindbody where they connect to the body wall or end blindly. Innervation to the muscle systems of Apatemon was examined by immunocytochemistry, using antibodies to known myoactive substances: the flatworm FMRFamide-related neuropeptide (FaRP), GYIRFamide, and the biogenic amine, 5-hydroxytryptamine (5-HT). Strong immunostaining for both peptidergic and serotoninergic components was found in the central nervous system and confocal microscopic mapping of the distribution of these neuroactive substances revealed they occupied separate neuronal pathways. In the peripheral nervous system, GYIRFamide-immunoreactivity was extensive and, in particular, associated with the innervation of all attachment structures; serotoninergic fibres, on the other hand, were localized to the oral sucker and pharynx and to regions along the anterior margins of the forebody.

Directed regrowth of axons from a misrouted nerve to their correct muscles in the limb of the adult newt

1984 ◽  
Vol 222 (1229) ◽  
pp. 477-489 ◽  
Keyword(s):  
Electron Microscopy ◽  
Extracellular Matrix ◽  
Nervous System ◽  
Nerve Regeneration ◽  
Body Wall ◽  
Cobalt Chloride ◽  
Light And Electron Microscopy ◽  
Growth Cones ◽  
The Body ◽  
Forearm Flexor

When the forearm flexor nerve (f.f.n.) of the newt forelimb is surgically rerouted to the ventral body wall, regrowth of axons occurs and these axons reinnervate the muscle targets of the f.f.n. This process of nerve regeneration has been studied in detail over a 12 week period by using light and electron microscopy, electrophysiology and nerve fibre tracking after filling with cobalt chloride. The regrowing axons were analysed by electron microscopy and it is shown that they derive from the rerouted nerve at the position at which the f.f.n. leaves its normal ventral limb pathway. Axons in the pathway do not originate from the cut end of the f.f.n. on the ventral body wall. The regrowing axons are identified within the body of the rerouted nerve and they leave the f.f.n. by growing through the perineurium. Schwann cells are invariably associated with the regrowing axons and the pathway through which the growth cones and neurites grow consists predominantly of extracellular matrix fibrils. The stages of maturation of the regenerated f.f.n. including fasiculation of neurites, myelination and reformation of a perineurium are also described. The results of the study are discussed in terms of current ideas as to how specific regeneration of a correct and functional peripheral nervous system is achieved in urodele amphibians.

Differentiation of Ectoderm Implanted into the Primordium of the Limb Bud in the Amphibian Embryo and its Influence upon the Limb

1946 ◽  
Vol 22 (3-4) ◽  
pp. 101-106
Author(s):  
WALTER BRANDT
Keyword(s):  
Body Wall ◽  
Distal Part ◽  
The Body ◽  
Limb Bud ◽  
Muscle Fibres ◽  
Tail Bud ◽  
Amphibian Embryo ◽  
Microscopical Analysis ◽  
Proximal Half ◽  
Host Embryo

1. A microscopical analysis was made concerning the differentiation of ectoderm cut from the tip of the tail-bud of an amphibian embryo (Amblystoma mexicanum, stages 35-37, Harrison) after its implantation into the primordium of the limb-bud of a host embryo 3-5 weeks after operation. 2. The ectoderm which lay deep in the tissues of the limb differentiated either into solid epithelial cords or into cysts. 3. The ectoderm which was attached outside the limb differentiated into notched ectodermal elevations which included a mesenchymal core. 4. A microscopical analysis was made concerning the development of deformities of limbs as the result of the operation. 5. The scapula may be divided into isolated pieces, bundles of muscle fibres separating the pieces from each other. 6. A supernumerary piece of cartilage can develop close to the cartilage of the scapula. 7. The suprascapula may be absent and its place taken by a mass of muscle fibres. 8. A phocomelias may be produced when the whole length of the humerus and the elbow-joint lies inside the body wall. In this case the implanted ectoderm covers the area where the limb would normally develop. 9. The humerus may be reduplicated. 10. The humerus may be too short. 11. The proximal half of the humerus may possess a diameter different from that of the distal half. 12. One skeletal element only of the forearm (radius or ulna) may be present when the place which would normally be occupied by one of these elements was taken by implanted ectoderm. 13. The elements of the carpus and of the hand may appear irregularly scattered throughout the tissues of the distal part of the limb. In these cases the implanted ectoderm was attached to the surface of the distal end of the limb. 14. The fingers can show: (a) abnormal positions, (b) abnormal numbers, (c) syndactylias, (d) one finger too long, others too short.

The musculature of Peripatus and its innervation

1980 ◽  
Vol 288 (1031) ◽  
pp. 481-510 ◽  
Keyword(s):  
Body Wall ◽  
Fibre Length ◽  
Gross Anatomy ◽  
Small Degree ◽  
The Body ◽  
Muscle Fibres ◽  
Neuromuscular Synapses ◽  
Thick Filaments ◽  
Small Muscle ◽  
Tubule Diameter

The musculature of the Onychophoran Peripatus dominicae , its ultrastructure and details of innervation are described. Significant differences were noted between its gross anatomy and that reported in previous accounts, notably in the presence of inner circular body wall muscle and a prominent, functionally significant, levator of the leg. The former is important in regard to the evolutionary position of the Onychophora while the latter helps us to understand the control of walking in a lobopodial leg, and therefore the evolution of arthropod locomotion, which was the focus of our interest. Individual muscle fibres are either directly or indirectly attached to the body wall by collagen. There is a small degree of branching of fibres, with or without anastomosis, near their insertions, but most are as long as the muscle of which they are part, and are unbranched except for an occasional thin arm, emerging at an angle, that becomes invaded by collagen fibres and inserts in the skin. Diameters of muscle fibres vary from 1 to 45 pm. They are invaginated by two separate systems of unique wide (0.3 pm) tubules, longitudinal and radial. These are lined with similar material to that forming the basement material of the sarcolemma, and also contain fine strands with collagen-type cross-banding that connect to collagen bundles outside the fibres. In addition there are narrow tubules of ordinary T-tubule diameter. Both wide and narrow tubules make contacts with sarcoplasmic reticulum cysternae. Dense Z bodies are attached to both kinds of wide tubule, to the inside of the sarcolemma, and are scattered, without any obvious array, in the sarcoplasm. Thin myofilaments emerge from the Z bodies parallel to the fibre axis. Thick filaments occur in clusters with a loosely hexagonal array, but without any regular relation to thin ones: relatively few orbits of thin around thick filaments were seen in many muscle fibres regardless of fibre length and conditions during fixation. A unique innervation pattern was found, consisting of a combination of muscle arm to nerve contacts, which appear to be the commonest, and nerve on muscle fibre synapses. At least 13 motor axons were found to supply each small muscle or cluster of muscle fibres in a large muscle. Each muscle arm simultaneously makes synaptic contact with 3 to 7 axons. Nerve on muscle junctions contain from 1 to 8 axons, each making synaptic contacts. The details of the postsynaptic endplate-specializations resemble those seen in mammalian endplates and are markedly different from both arthropod and annelidan neuromuscular synapses.

scholarly journals THE STRUCTURE OF THE SMOOTH MUSCLE FIBRES IN THE BODY WALL OF THE EARTHWORM

1957 ◽  
Vol 3 (1) ◽  
pp. 111-122 ◽  
Author(s):  
Jean Hanson
Keyword(s):  
Smooth Muscle ◽  
Phase Contrast ◽  
Body Wall ◽  
Longitudinal Muscle ◽  
Lumbricus Terrestris ◽  
Mirror Image ◽  
The Body ◽  
The Other ◽  
Muscle Fibres ◽  
Muscle Coat

1. The structure of the smooth muscle fibres in the longitudinal muscle coat of the body wall of Lumbricus terrestris has been investigated by phase contrast light microscopy and electron microscopy. 2. The muscle fibre is ribbon-shaped, and attached to each of its two surfaces is a set of myofibrils. These are also ribbon-shaped, and they lie with their surfaces perpendicular to the surfaces of the fibre, and their inner edges nearly meeting in the middle of the fibre. These fibrils are oriented at an angle to the fibre axis, and diminish greatly in width as they approach the edge of the fibre. The orientation of the set of fibrils belonging to one surface of the fibre is the mirror image of that of the set belonging to the other surface; thus, when both sets are in view in a fibre lying flat on one face, the fibre exhibits double oblique striation. A comparison of extended and contracted fibres indicates that as the fibre contracts, the angle made between fibre and fibril axes increases (e.g. from 5 to 30°) and so does the angle made between the two sets of fibrils (e.g. from 10 to 60°). 3. The myofibril, throughout its length, contains irregularly packed filaments, commonly 250 A in diameter, which are parallel to its long axis and remain straight in contracted muscles. Between them is material which probably consists of much finer filaments. Thus A and I bands are absent. 4. Bound to one face of each fibril, but not penetrating inside it, is a regularly spaced series of transverse stripes. They are of two kinds, alternating along the length of the fibril, and it is suggested that they are comparable to the Z and M lines of a cross-striated fibril. The spacing of these stripes is about 0.5 µ ("Z" to "Z") in extended muscles, and 0.25 µ in contracted muscles. A bridge extends from each stripe across to the stripeless surface of the next fibril.

The spatial relationship between the musculature and the 5-HT and FMRFamide immunoreactivities in cercaria, metacercaria and adult Opisthorchis felineus (Digenea)

2010 ◽  
Vol 55 (2) ◽  
Author(s):  
Oleg Tolstenkov ◽  
Nadezhda Terenina ◽  
Elena Serbina ◽  
Margaretha Gustafsson
Keyword(s):  
Nervous System ◽  
Body Wall ◽  
General Pattern ◽  
Spatial Relationship ◽  
The Body ◽  
Muscle Fibres ◽  
Neuromuscular System ◽  
Opisthorchis Felineus ◽  
Larval Stages ◽  
The Individual

AbstractThe organisation of the neuromuscular system in cercariae, metacercariae and adult Opisthorchis felineus was studied. The patterns of nerves immunoreactive (IR) to antibodies towards serotonin (5-HT) and FMRFamide are described in relation to the musculature, stained with TRITC-conjugated phalloidin. The general organisation of the musculature in the body wall, suckers, pharynx, intestine and sphincter of the excretory pore remains the same from the larval stages to the adult worms. However, the diameter of the individual muscle fibres increases distinctly in the adult worms. The general pattern of 5-HT IR fibres in cercariae, metacercariae and adult O. felineus remains the same. Despite the large increase in body size, the number of 5-HT IR neurones remains almost the same in the cercariae and metacercariae and only a modest increase in number of neurones was observed in the adult worms. Thus the proportion of 5-HT IR neurones/body mass is greatest in the actively moving cercariae. Anti-FMRFamide stains the nervous system strongly.

Neuromuscular Junctions in the Body Wall Muscles of the Earthworm, Lumbricus Terrestris Linn

1970 ◽  
Vol 7 (1) ◽  
pp. 263-271
Author(s):  
P. J. MILL ◽  
M. F. KNAPP
Keyword(s):  
Synaptic Vesicles ◽  
Body Wall ◽  
Neuromuscular Junctions ◽  
Lumbricus Terrestris ◽  
The Body ◽  
Dense Material ◽  
Muscle Fibres ◽  
Membrane Material ◽  
Axonal Membrane ◽  
Body Wall Muscles

The fine structure of the neuromuscular Junctions in the body wall muscles of the earthworm is described. The segmental nerves send branches into the muscle layers. Axons in the nerve branches contain numerous synaptic vesicles and contact is established between these axons and muscle fibres or muscle tails; the latter may extend for a considerable distance from the muscle fibre. The cleft between the axolemma and sarcolemma is 85-120 nm wide and contains basement membrane material. At intervals small aggregations of electron-dense material are attached to the axonal membrane and synaptic vesicles are associated with these. The sarcolemma bears rather larger masses of dense material and is also specialized extracellularly.

scholarly journals Muscular and Hydrostatic Action in the Sea-Anemone Metridium Senile (L.)

1950 ◽  
Vol 27 (3) ◽  
pp. 264-289 ◽  
Author(s):  
E. J. BATHAM ◽  
C. F. A. PANTIN
Keyword(s):  
Body Wall ◽  
Circular Muscle ◽  
Muscular Activity ◽  
Isometric Tension ◽  
The Body ◽  
Muscle Fibres ◽  
Skeletal System ◽  
Metridium Senile ◽  
Pressure Changes ◽  
Muscular Action

1. In contrast with most other Actinians, Metridium senile exhibits a great variety of shapes of the body. These are brought about by continual slow muscular activity. The mechanics of muscular action are discussed. The action of most of the muscles is extremely slow. An isotonic contraction of the parietal muscles requires 40-60 sec. to reach its maximum and many minutes to relax. The body wall is capable of extension by about 400%. There are limits to extensibility in the normal animal. The mechanisms by which the animal itself increases or reduces extension by controlling its coelenteric volume are described. Fluid is gained chiefly through the siphonoglyph, though under certain conditions there may be suction into the coelenteron. Fluid is lost chiefly through reflex opening of the mouth. From time to time Metridium empties itself of fluid, and then refills in a few hours. A rate of refilling of 14 c.c./hr. has been measured. 2. Pressure changes in the coelenteron which occur during activity show that both retraction and extension of the column are active processes involving a rise in pressure which enforces reciprocal extension of the opposing musculature. 3. The relation of normal activity and shape to the coelenteric pressure is shown. This average pressure is extremely low; about 2-3 mm. of water. In a moderately filled unstimulated animal the natural muscular contractions are accompanied by a rise in pressure not generally exceeding 6-7 mm. of water. In such animals the natural contractions are of considerable extent, reaching over 30% of the body length. 4. By experimental inflation of the coelenteron with sea water, the system can be made to work more isometrically. The extent of movement is reduced and the animal may appear inactive. The presence of considerable though ineffective muscular activity is shown by the fact that large pressure changes (up to about 12 mm. of water) now take place. By raising the coelenteric pressure increased contractile activity in the body wall may actually reduce the extent of movement. 5. The isometric pressure which the body wall can develop in the coelenteron has been estimated. Pressures developed during natural contractions of a moderately filled animal demand muscular tensions in the body wall ranging between 20 and 50% of the isometric tension. The range of tension corresponds to that which would be most mechanically efficient if Metridium muscle resembles that of other animals. 6. An estimate is deduced from the coelenteric pressure of the isometric tension developed by the circular muscle of the column of Metridium. It is about 3-5 g./cm. of body wall transverse to the muscle. This is in agreement with direct observation of the isometric tension developed by strips of circular muscle. This tension in the column may correspond to a tension of 40 kg./sq.cm. of the individual muscle fibres and is very much greater than the values obtained from the frog's sartorius. 7. The extensive responses of the powerful retractor muscles involve much greater pressures (40-100 mm.) than those against which the column muscles can operate. The development of these muscles is related to the necessity of speed of action in a system undergoing great deformation. 8. Muscular action in a hydrostatic skeletal system is contrasted with that in the jointed skeletal system of Vertebrates and Arthropods. The former system is characterized by slowness of action and great change of length. In contrast with the Vertebrate skeletal system, in the hydrostatic system reciprocal muscular action is not localized. The movement of every muscle influences the mechanical conditions of every other in the system. Each muscle has two actions, a local direct action, and an indirect action, as in the elongation of Metridium on contraction of the circular muscles. The consequences of this are discussed.

scholarly journals The Contractile Mechanism in Obliquely Striated Body Wall Muscle of the Earthworm, Lumbricus Terrestris

1971 ◽  
Vol 8 (2) ◽  
pp. 413-425 ◽  
Author(s):  
M. F. KNAPP ◽  
P. J. MILL
Keyword(s):  
Body Wall ◽  
Striated Muscle ◽  
Lumbricus Terrestris ◽  
The Body ◽  
Band Width ◽  
Physiological Data ◽  
Muscle Fibres ◽  
Contraction Mechanism ◽  
Cross Links

Obliquely striated muscle fibres from the longitudinal and circular layers of the body wall of the earthworm were prepared in extended and contracted states for study in the electron microscope. Contracted fibres differ from extended ones in the following respects: (i) the I-bands are narrower, (ii) the A-bands are wider, and (iii) there are more rows of thick myofilaments in each A-band. The arrangement of the thick and thin myofilaments in interdigitating arrays and the occurrence of cross-links between the 2 types of myofilament indicate a classical sliding-filament mechanism of contraction as in cross-striated muscle, resulting in a reduction in the I-band width. The increase in the A-band width could be due to a moving apart of the myofilaments during contraction to preserve constant volume of the lattice. The third change, the increase in the number of rows of thick myofilaments in the A-band, can be explained only by a shearing of these filaments past one another in such a way as to increase the amount of their overlap. The role of the sliding-filament and shearing contraction mechanisms in bringing about the changes observed in earthworm muscle fibres is considered and the possible correlation of these mechanisms with certain physiological data is discussed. The function of the sarcoplasmic reticulum in the transmission of impulses to the interior of the fibre and/or in the control of the contraction mechanism is also discussed.

The Organization of the Muscular System of Metridium senile

1951 ◽  
Vol s3-92 (17) ◽  
pp. 27-54
Author(s):  
E. J. BATHAM ◽  
C. F.A. PANTIN
Keyword(s):  
Body Wall ◽  
Functional Organization ◽  
Circular Muscle ◽  
Muscle Layer ◽  
The Body ◽  
Whole Body ◽  
Retractor Muscle ◽  
Muscle Fibres ◽  
Muscular System ◽  
Longitudinal Contraction

I. The muscular system of Metridium consists of fields of relatively short muscle-fibres. In extension these may exceed I mm. in length but are only about 0.5µ thick. They can shorten to about a fifth of the extended length. The fibres consist almost entirely of densely staining material. They form a connected network. At least in some cases the cells seem to be in contact rather than to form syncytial connexions. 2. Deformation of the body-wall is in part controlled by the contractility of the muscle-fibres and in part by the properties of the mesogloea. Longitudinal contraction of the body-wall is accompanied by great thickening of the substance of the mesogloea. That part of the mesogloea which carries the circular muscle-fibres of the body-wall does not thicken. It buckles, thereby throwing the muscular layer into folds. Buckling occurs during the shortening of almost every actinian tissue. The familiar folding seen in cross-sections of the retractors is a special case of excessive buckling which is permanent. 3. A natural limit to the extension of anemone tissue is reached when the muscle-layer is completely unbuckled. If contraction proceeds to a maximum, there is a second order of buckling by which the whole body-wall is thrown into folds. Con-traction ca n then proceed no further. 4. The function of the muscle-fields is analysed. The youngest cycles of mesenteries (‘imperfect microcnemes’) supply the longitudinal musculature of the column (parietal muscle). The older ‘imperfect retractor-bearers’ have only feeble parietal musculature, but possess a retractor muscle connecting the oral with the pedal disk. The perfect mesenteries have a similar organization to the imperfect retractor-bearers, and parti-cularly in the non-directive perfect mesenteries there is a well-developed sheet of radial (exocoelic) muscle whose reflex contraction opens the mouth. The vertical endocoelic muscle-fibres of all non-directive mesenteries fan out on to the pedal disk. On the exocoelic side, the parieto-basilarfans out from the pedal disk to the body-wall. As usual, the muscle-fields of the directives are developed on opposite sides from those of the non-directives. 5. The muscular plan of the pedal disk is compared with the tube foot of Asterias as described by J. E. Smith. There is a significant functional similarit y in the opera-tion of vertical, oblique, and radial muscles (basilars) bearing on the adhesive disk. The circular layer of the actinian foot has no analogue in the tube foot. It is primarily concerned with locomotion and not with adhesion. 6. The functional organization of the oral disk and tentacles is discussed. It differs from the rest of the body in the retention of ectodermal longitudinal muscle. This layer is responsible for the special movements executed in feeding. The significance of its physiological separation from the endodermal system is noted.

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