A histological and histochemical study of the development of the amnioallantois in the chick, Gallus domesticus

1970 ◽  
Vol 48 (5) ◽  
pp. 1079-1086 ◽  
Author(s):  
T. P. Kenny ◽  
M. A. Gibson

The amnioallantoic membrane is composed of four layers. (1) An inner amnionic epithelium which is a stratified layer during most of the incubation period. This layer stains positively for glycogen, ribonucleic acid, and neutral and acidic lipids and appears to be most active during the 15 to 17 days of incubation period. (2) A muscle layer composed of dorsoventrally and anteroposteriorly directed bands. During the early incubation stages these bands are organized to form the muscle configurations known as "cross-figures." During the later incubation stages, the organization of these muscle layers is disrupted by invasions of connective tissue and fat. (3) A connective tissue layer which includes blood and lymphatic vessels. (4) An outer allantoic epithelium which is rich in secretory granules. These granules include a sulfated mucopolysaccharide component. The activity of the allantoic epithelium increases progressively during the incubation period and is at peak activity at the 17- to 19-day incubation stage. During the final stages of incubation all layers show signs of decreased activity and degeneration.

2006 ◽  
Vol 57 (5) ◽  
pp. 497 ◽  
Author(s):  
Parichart Laksanawimol ◽  
Praneet Damrongphol ◽  
Maleeya Kruatrachue

The brood pouch of seahorses can be divided into four sequential stages based on the characteristics of the altered tissue layers during gestation: the normal stage, the embryo-carrying stage, the embryo-release stage and the repair stage. The brood pouch is composed of a folded inner pseudostratified columnar epithelium and a smooth outer stratified cuboidal epithelium. Three tissue layers between the inner and the outer epithelia are an inner loose connective tissue layer, a middle smooth muscle layer and an outer dense irregular connective tissue layer. In the normal stage, the inner loose connective tissue layer is thick and vascularised with small blood vessels; the muscle layer consists of scattered unorganised muscle fibres. In the embryo-carrying stage, the inner epithelial and inner loose connective tissue layers become distended and highly vascularised with enlarged blood vessels. In the embryo-release stage, the inner loose connective tissue layer is extensively vascularised with very large blood vessels and the smooth muscle fibres invade the outer dense irregular connective tissue layer. Structures altered during gestation gradually resume their normal condition in the repair stage. Extensive vascularisation of the brood pouch during gestation suggests an intricate paternal–embryo relationship implying other significant roles besides protective function of the pouch.


2009 ◽  
Vol 110 (4) ◽  
pp. 648-655 ◽  
Author(s):  
Tomio Sasaki ◽  
Tadahisa Shono ◽  
Kimiaki Hashiguchi ◽  
Fumiaki Yoshida ◽  
Satoshi O. Suzuki

Object The authors analyzed the tumor capsule and the tumor–nerve interface in vestibular schwannomas (VSs) to define the ideal cleavage plane for maximal tumor removal with preservation of facial and cochlear nerve functions. Methods Surgical specimens from 21 unilateral VSs were studied using classical H & E, Masson trichrome, and immunohistochemical staining against myelin basic protein. Results The authors observed a continuous thin connective tissue layer enveloping the surfaces of the tumors. Some nerve fibers, which were immunopositive to myelin basic protein and considered to be remnants of vestibular nerve fibers, were also identified widely beneath the connective tissue layer. These findings indicated that the socalled “tumor capsule” in VSs is the residual vestibular nerve tissue itself, consisting of the perineurium and underlying nerve fibers. There was no structure bordering the tumor parenchyma and the vestibular nerve fibers. In specimens of tumors removed en bloc with the cochlear nerves, the authors found that the connective tissue layer, corresponding to the perineurium of the cochlear nerve, clearly bordered the nerve fibers and tumor tissue. Conclusions Based on these histological observations, complete tumor resection can be achieved by removal of both tumor parenchyma and tumor capsule when a clear border between the tumor capsule and facial or cochlear nerve fibers can be identified intraoperatively. Conversely, when a severe adhesion between the tumor and facial or cochlear nerve fibers is observed, dissection of the vestibular nerve–tumor interface (the subcapsular or subperineurial dissection) is recommended for preservation of the functions of these cranial nerves.


2007 ◽  
Vol 44 (3) ◽  
pp. 261-268 ◽  
Author(s):  
Nancy J. M. van Hees ◽  
Johan M. Thijssen ◽  
Rinske W. Huyskens ◽  
Gert Weijers ◽  
Maartje M. Nillesen ◽  
...  

Objective: To investigate the feasibility of echographic imaging of healthy and reconstructed cleft lip and to estimate tissue dimensions and normalized echo level. Methods: Echographic images of the upper lip were made on three healthy subjects and two patients using a linear array transducer (7 to 11 MHz bandwidth) and a noncontact gel coupling. Tissue dimensions were measured using calipers. Echo levels were calibrated and were corrected for beam characteristics, gel path, and tissue attenuation using a tissue-mimicking phantom. Results: At the central position of the philtrum, mean thickness (SD) of lip loose connective tissue layer, orbicularis oris muscle, and dense connective layer was 4.0 (0.1) mm, 2.3 (0.7) mm, and 2.2 (0.7) mm, respectively, in healthy lip at rest; and 4.1 (0.9) mm, 3.8 (1.7) mm, and 2.6 (0.6) mm, respectively, in contracted lip. Mean (SD) echo level of muscle and dense connective tissue layer with respect to echo level of lip loose connective tissue layer was −19.3 (0.6) dB and −10.7 (4.0) dB, respectively, in relaxed condition and −20.7 (1.5) dB and −7.7 (2.3) dB, respectively, in contracted state. Color mode echo images were calculated, showing lip tissues in separate colors and highlighting details like discontinuity of the orbicularis oris muscle and presence of scar tissue. Conclusions: Quantitative assessment of thickness and echo level of various lip tissues is feasible after proper echographic equipment calibration. Diagnostic potentials of this method for noninvasive evaluation of cleft lip reconstruction outcome are promising.


Author(s):  
J. B. Buchanan ◽  
B. E. Brown ◽  
T. L. Coombs ◽  
B. J. S. Pirie ◽  
J. A. Allen

The connective tissue layer of the large intestines of Brissopsis and Echinocardium spp. is shown to contain a massive quantity of ferric iron in the form of ferric phosphate. The ferric phosphate is present as a granular extracellular deposit. In large mature specimens of Brissopsis, the weight of iron present may account for almost 30% of the dry weight of large intestinal tissue. The iron deposit appears to be cumulative with age. It is speculated that the deposit is derived from oxidative deposition of a soluble ferrous salt ingested in reducing conditions.


1969 ◽  
Vol 47 (3) ◽  
pp. 323-331 ◽  
Author(s):  
B. A. Flumerfelt ◽  
M. A. Gibson

The chorioallantoic membrane is composed of three layers. (1) An outer chorionic epithelium consisting of a thin outer layer of cells, an inner stratified cell layer, and a central blood sinus lined with flattened ectodermal cells. (2) A middle connective tissue which provides support and a pathway for the distribution of blood and lymphatic vessels. Numerous capillaries pass from this layer to the chorionic sinuses. (3) An inner allantoic epithelium composed of secretory cells. The components of all three layers increase in number and concentration during the first part of the incubation period. After day 17, however, there is a rapid decrease in the composition of each layer. The allantoic epithelium is rich in secretory granules. These granules include a sulfated mucopolysaccharide component. It is suggested that the liberation of this secretion provides a surface coating which protects the underlying tissues against the increasing toxicity of the allantoic contents.


1980 ◽  
Vol 88 (1) ◽  
pp. 281-292
Author(s):  
E. FLOREY ◽  
M. A. CAHILL

Isolated tube feet of Strongylocentrotus franciscanus contract briefly when the outer epithelium is touched. Similar twitch-like contractions can be induced by electrical stimulation of the outer surface of the tube foot. These responses appear to be chemically mediated. The following evidence indicates that the transmitter substance may be acetylcholine (ACh): ACh causes muscle contraction. This effect and that of electrical stimuli is potentiated by anticholinesterase agents and is antagonized by cholinergic blocking agents. Anaesthesia with chloralhydrate or chloretone abolishes responsiveness to mechanical or electrical stimulation but not to ACh. Desensitization with carbachol prevents responses to ACh and to mechanical or electrical stimulation. There are no neuromuscular synapses and no axons can be detected which cross the connective tissue layer which separates the muscle fibres from the subepithelial nerve plexus. The latter is known to contain conspicuous amounts of ACh; nerve terminals containing clear vesicles invest the outer surface of the connective tissue layer. All evidence indicates that chemical transmission involves diffusion of ACh (released from activated nerve terminals) across this connective tissue layer which is around 5 μm thick in fully extended tube feet but may have a thickness of 20 or even 25 μm in less extended ones. Calculations based on equations describing transmitter diffusion prove the feasibility of such a mechanism. Note:


2012 ◽  
Vol 28 (2) ◽  
pp. 75-79
Author(s):  
K. A. Ferdous ◽  
M. N. H. Parvez ◽  
M. T. Rahman

Structure and postnatal development of vagina in 21 ISA brown chickens was studied at three, 23 and 46 weeks of age. At 3 weeks of age the vagina was narrower and thicker then the uterus. The undifferentiated wall of vagina consisted of low primary mucosal folds lined by simple columnar epithelium to a pseudostratified ciliated columnar epithelium and a connective tissue layer underneath. At three weeks of age, scattered smooth muscle fibres were in the subepithelial connective tissue layer. Rapid structural changes occurred at 23 weeks of age in the adult bird, mucosal folds were narrowed and tongue-shaped. Lamina propia was devoid of glands and contained lymphocytes. Tunica muscularis was well developed at 23 and 46 weeks.DOI: http://dx.doi.org/10.3329/bvet.v28i2.10676Bangl. vet. 2011. Vol. 28, No. 2, 75 – 79


1906 ◽  
Vol s2-50 (199) ◽  
pp. 479-492
Author(s):  
J. T. GRADON

We have seen that our trabeculæ are entirely epiblastic in origin, for we have shown that the entrance of the nerve-fibres along the ventral wall of the embryonic optic stalk produces a confluence and stretching of the protoplasmic fibrils of the epiblastic cells of the stalk, which result in a complex framework of supporting elements radiating in every direction from the border of each nucleus of the stalk, and that this complex framework afterwards becomes more or less differentiated into a transverse, oblique, and longitudinal trabeculæ with the multiplication of the nuclei of the stalk and without any admixture of mesoblastic cells, for we have also shown that the nerve-fibres lie, throughout the whole of their course, in the optic stalk, within the membrana limitans externa, on the outside of which we have followed the gradual formation of the connective-tissue layer of the pial sheath. We have noticed the obliteration of the lumen of the stalk, aud have ascribed it to various causes operating within the stalk itself and outside it, though chiefly to the ingrowth of nerve-fibres. We have seen that, in the development of the optic nerve of the frog there is a period of slow growth, followed by one of great activity, and we have felt justified in ascribing this sudden outburst of activity to a greatly increased flow of lymph into it by means of the elaborate system of minute channels that follow the course of each fibril of the epiblastic trabeculas, and consequent upon the formation of the arachnoid sheath and the enclosure of the subarachnoidal lymph We have therefore shown that the cells of the optic stalk perform the following three functions : 1st. They conduct the nerve-fibres, which, in their turn, resolve the constitution of the cells of tbe stalk, so that they--2nd. Provide the nerve-fibres with a supporting framework which--3rd. Provides the whole interior of the optic nerve with an elaborate system of minute lymph channels.


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