Defn: The condition of an invaginatedorgan or part.
At the same time the ectoderm covering the side of the head thickens and becomes invaginated to form the lens vesicle (see figs.
The superficial layer of head ectoderm, from which the lens has been invaginated and separated, becomes the anterior epithelium of the cornea (fig.
This invaginated layer of cells, brought into a new position with regard to its environment, becomes the endoderm and receives the stimulus to assume the character appropriate to the new environment.
Certain cells do not become invaginated into the segmentation cavity because they possess groups of determinants that impel them to the assumption of inner layer characters.
The cells forming the invaginated layer become gradually more columnar than the remaining cells, and constitute the hypoblast; and a structural distinction between the epiblast and hypoblast is thus established.
The invaginated cells forming the dorsal wall of the mesenteron soon become divided into a pigmented hypoblastic epithelium adjoining the lumen of the mesenteron (fig.
The epiblast along the line of the invaginated cells soon becomes thickened, and forms a medullary plate, which is not very distinct in surface views.
The two cords unite in the median line, and Hatschek, in accordance with his general view on this subject, states that their junction is effected by means of a median cord of invaginated epiblast.
In Mammals there appear to be some mesoblast cells invaginated with the lens, which are not improbably employed in the formation of the vessels of the so-called membrana capsulo-pupillaris.
The fact of these plates originating from an invaginated layer can only be regarded in the light of an approximation to the primitive type found in Amphioxus.
This patch soon becomes invaginated in the form of a pit (fig.
Ranvier[128] finds that the muscles of the sweat-glands are developed from the inner part of the layer of epiblast cells, invaginated to form these glands.
The invaginated portion is termed the intussusceptum, and the lower portion which it enters is known as the intussuscipiens.
In some cases the invaginated gut may be felt protruding through the sphincter.
Their contraction causes the proboscis to be invaginated into its cavity (fig.
Then follows the phenomenon of gastrulation, by which one-half of the blastula is invaginated into the other, so as to obliterate the segmentation cavity.
The oldest leaves were outside, the youngest within, so that the appearance presented was as if the summit of the axis had been pushed or drawn in, much as the finger of a tight glove might be invaginated in withdrawing it from the hand.
On the contrary, the evidence derived from this source supports the ordinary opinion that the carpels are invaginated within the expanded top of the flower-stalk and more or less adherent to it.
In the end this invagination goes so far that the outer or invaginated part of the blastoderm lies close on the inner or non-invaginated part (Figure 1.
The principle is to plug up the passage by the mechanical presence of the invaginated skin, the plug being retained in position by adhesive inflammation between it and the edges of the dilated ring.
Signoroni modified this by fixing the invaginated skin by a piece of female catheter, retained in its place by transfixion by three harelip needles, tied by twisted sutures.
The function of this pouch is to form the spermatophore, which is an elastic tube formed of structureless secretion and invaginated into itself.
The ovary forms a large projection into the genital coelom, and the coelomic epithelium is deeply invaginated into the mass of the gonad, so as to constitute an ovarian cavity communicating with the coelom by a narrow aperture.
The decision does not rest upon the answer to the question, Are these cells in reality the invaginated cells of a single-celled blastula?
It may happen that the part invaginated is the optic sense-plate itself, as would be the case if in the former figure, instead of C, the part B was modified to form a sense-plate.
The simplest way to do this is by a process of invagination, in consequence of which food particles are swept into the invaginated part and then absorbed.
Unless theinvaginated portion of the gut becomes strangulated, probably no symptoms except constipation will be appreciable.
In some rare instances he recovers, even though the invaginatedportion of the gut has become strangulated.
The invaginated portion may be slight--2 or 3 inches only--or extensive, measuring as many feet.
Separation of the invaginated portion and its expulsion, according to Leichtenstern, in the majority of cases takes place from the eleventh to the twenty-first day, but in chronic cases it is often delayed for months.
Dislodging the invaginated bowel is not always practicable, and the opium or expectant treatment may end in spontaneous cure by the bowel righting itself or by sloughing of the intussuscepted part.
The concavity of this curve looks {845} toward the mesenteric edge of the invaginated portion of bowel, and the convexity toward the opposite side of the receiving portion.
In this instance the invaginatedportion is tightly compressed by the valve, and strangulation is speedy and complete.
Leichtenstern believes that the paretic portion is turned in and invaginated into the normal bowel below, and that the clinical course of intussusception and post-mortem appearance correspond with this explanation.
The entering or invaginated portion does not always lie in the axis of the enveloping tube, but is more or less curved, until very often its lower orifice is in contact with the wall of the outer layer.
Where primitively the hypoblast cells are very bulky, though invaginated in a normal way, the wall of the hepatic region becomes immensely swollen with food-yolk, e.
More especially from the figures given by Agassiz, and from the explanation of his plates, it would seem that a large chamber is formed in the hypoblast at the end of the invaginated tube, into which this tube soon opens (fig.
The blastopore soon narrows to become the permanent anus, while the invaginated hypoblast forms a small prominence with an imperfectly developed lumen, which does not nearly fill up the segmentation cavity (fig.
At the aboral pole the epiblast becomes thickened and invaginated to form the shell-gland, and shortly afterwards the velum and foot are formed in the normal way, and a stomodaeum appears close to the ventral edge of the velum (fig.
This difference in the position of the yolk is rendered possible by the fact that the invaginated hypoblast cells in Palaemon do not, at first, form a continuous layer enclosing a central cavity, while they do so in Astacus.
With the rapid growth of the larva the invaginated mesenteron becomes relatively reduced in size.
While these changes are taking place, there are budded off from the invaginated discs a number of fatty cells, which fill up the space between the discs and the archenteron, and eventually form the mesoblastic reticulum.
C) external layer of the invaginated discs as the external skin of the young Nemertine.
By the time the larva has become free, the semi-invaginated granular cells have increased in bulk and become everted so as to project very much more prominently than in the encapsuled state.
The invaginated tube would seem to give rise to the so-called stomach, while the chamber at its aboral extremity is no doubt the infundibulum, which as may be gathered from Kowalevsky's statements, is lined by a flattened epithelium.
Dieck finds that in Cephalothrix the invaginated mass simply vanishes.
Barrois' statements about the fusion of the syncytium derived from the epiblast cells with the invaginated cells must be regarded as very doubtful.
The invaginated cells (derived from the division of the four big cells) form the endoderm or arch-enteron; the outer cells are the ectoderm.
To the right (in the figure) of the rectal peduncle is seen the deeply invaginated shell-gland ss, with a secretion sh protruding from it.
The mass of the arch-enteron or invaginated endodermal sac has taken on a bilobed form, and its cells are swollen (gs and tge).
The dead outer layer or ectocyst lines part of the portion thus invaginated and forms the walls of a cavity within the orifice.
The diaphragm, however, does not constitute the limit of the invaginated portion of the zooecium, for the living inner wall or endocyst is dragged in still further and forms a sheath round the retracted tentacles.
The embryo is invaginated into the yolk, but the surface edges of the blastoderm do not close over, so that a groove or pore puts the insunken space that represents the amniotic cavity into communication with the outside.
Heymons believes that the "dorsal organ" in the embryos of the lower Arthropoda corresponds with the region invaginated to form the serosa of the hexapod embryo.
The embryo of a moth, a dragon-fly or a bug is invaginated into the yolk at the head end, the portion of the blastoderm necessarily pushed in with it forming the amnion.
The embryo has increased in size by accumulation of liquid between the outer and the invaginated cells.
These invaginated cells are the arch-enteron; they proliferate and give off branching cells, which apply themselves (fig.
A new aperture, m, the mouth, has eaten its way into the invaginated endodermal sac, and the cells pushed in with it constitute the stomodaeum.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "invaginated" in a variety of sentences. We hope that you will now be able to make sentences using this word.
