Embryo Sentence Examples

After fertilization the female cell, now called the oospore, divides and part of it develops into the embryo (new sporophyte), which remains dormant for a time still protected by the ovule which has developed to become the seed.

The name expresses the most universal character of the class, the importance of which was first noticed by John Ray, namely, the presence of a pair of seed-leaves or cotyledons, in the plantlet or embryo contained in the seed.

Cuscuta has a thread-like, spirally twisted embryo with no trace of cotyledons.

The seeds are filled with the large embryo, the two cotyledons of which are variously folded.

By this time the embryo has all the organs of the adult perfected save only the reproductive; these develop only when the first host is swallowed by the second or final host, in which case the parasite attaches itself to the wall of the alimentary canal and becomes adult.

A, Larva which has just left brood-pouch; B, longitudinal section through a somewhat later stage; C, the fully formed embryo just before fixing - the neo-embryo of Beecher.

It is absurd to call the larva of a newt or of a Caecilian a tadpole, nor is the free-swimming embryo of a frog as it leaves the egg a tadpole.

In the seed-forming plants (Phanerogams) one or more primary leaves (cotyledons) are already formed in the resting embryo.

The rows of cells from which the laticiferous vessels are formed can be distinguished in many cases in the young embryo while still in the dry seed (Scott), but the latex vessels in process of formation are more easily seen when germination has begun.

The seeds are minute and innumerable; they contain a small rudimentary embryo surrounded by a thin loose membraneous coat, and are scattered by means of hygroscopic hairs on the inside of the valves which by their movements jerk out the seeds.

Lecaillon (1898) on various leaf beetles, tend to show that the organ " in the embryos of the lower Arthropoda corresponds with whole of the " mid-gut " arises from the proliferation of cells at the the region invaginated to form the serosa of the hexapod embryo.

They do not long persist in the embryo, but disappear, and the area each one occupied becomes part of the sternite.

The ganglia become greatly changed in position during the later life, and it is usually said that there are only ten pairs of abdominal ganglia even in the embryo.

The germ band evidently marks the ventral aspect of the developing insect, whose body must be completed by the extension of the embryo so as to enclose the yolk dorsally.

The prae-genital somite, after appearing in the embryo, either is obliterated (Scorpio, Galeodes, Opilio and others) or is retained as a reduced narrow region of the body, the " waist," between prosoma and mesosoma.

Embryo taken out of seed.

Weismann has also ingeniously argued from the structure of the egg-cell and sperm-cell, and from the way in which, and the period at which, they are derived in the course of the growth of the embryo from the egg - from the fertilized egg-cell - that it is impossible (it would be better to say highly improbable) that an alteration in parental structure could produce any exactly representative change in the substance of the germ or sperm-cells.

In many embryo Lamellibranchs a centro-dorsal primitive shell-gland or follicle has been detected.

Cohnheim's hypothesis of " embryonic residues " provides that early in the development of the embryo some of the cells, or groups of cells, are separated from their organic continuity during the various foldings that take place in the actively growing embryo.

Some workers regard certain appearances in dividing cells found in cancer as evidence of a reversion of the somatic cell to the germcell type (heterotypical), otherwise found only in the process which results in the formation of an embryo.

This fact gave rise in ancient times to the false idea that the tapeworm originated from the union of these segments; and in modern times it has led to the view that the tapeworm is not a segmented organism (the monozoic view), but is a colony composed of the scolex which arises from the embryo and of the proglottides, which are asexually produced buds that, upon or before attaining their full size and maturity, become separated, grow, and, in some cases, live freely for a time, just as the segments of a strobilating jelly-fish grow, separate and become sexual individuals (the polyzoic view).

The embryo is provided with ten hooks, and appears to select Lamellibranchs (Mactra) for its intermediate host.

G, six-hooked embryo, highly magnified.

The egg gives rise in the uterus to a six-hooked embryo, which reaches the first host in a variety of ways.

In this way bladders as large as an orange and containing secondary bladders, A each with a scolex, may arise from a single embryo.

The embryo undergoes differentiation into an outer layer of cells that produce a chitinoid coat, a middle layer of cells, and a central spherical hexacanth body closely enveloped by the middle coat.

Arrived in the intestine of the intermediate host, the hooked embryo is set free and works its way to some distant site.

On this view, therefore, at least two asexual generations (embryo and scolex) alternate with a sexual one (proglottides); and in the case of Staphylocystis the cyst contains two asexually produced generations, so that in such forms three stages (embryo, primary scolex-buds, secondary scolices) intervene between the proglottis of a Cestode and that of its offspring.

On this view, multiple scolices are, therefore, not buds, but an example of the unlocalized organization of the embryo such as occurs in other groups of animals, and is demonstrated by experiment.

In North Germany the mature tapeworm was found on post-mortem examination once in every 200 bodies examined, while its embryo, the Cysticercus cellulosae, was found in in every 76 bodies.

In the Taenia solium it takes 3 to 3z months from the time of ingestion of the embryo to the passage of the matured segments, but in the Taenia saginata the time is only about 60 days.

The eggs are comparatively few, and development is direct, the embryo after reaching its host remaining attached to it for life.

This anomalous phenomenon is still obscure, for we do not yet know whether the second embryo is developed sexually or asexually from the first.

If the egg with its contained embryo falls into water E (All from Marshall and Hurst, after Thomas.) FIG.

The ovicells are modified zooecia, and contain numerous embryos which in the cases so far investigated arise by fission of a primary embryo developed from an egg.

The ovicells commonly found as globular swellings surmounting the orifices are not direct modifications of zooecia, and each typically contains a single egg or embryo.

In the Cyclostomata the primary embryo undergoes repeated fission without developing definite organs, and each of the numerous pieces so formed becomes a free larva, which possesses no alimentary canal.

None the less it is easy to find it in embryo in the speculations of the essentially European philosophers of Greece.

In some families, as many freshwater snakes, the sea snakes, Viperinae and Crotalinae, the eggs are retained in the oviduct until the embryo is fully developed.

When ripe the two carpels separate in the form of two valves and liberate a large number of seeds, each provided at the base with a tuft of silky hairs, and containing a straight embryo without any investing albumen.

The female lays her egg in the egg of a small ermine moth (Hyponomeuta) and the egg gives rise not to a single embryo but to a hundred, which develop as the host-caterpillar develops, being found at a later stage within the latter enveloped in a flexible tube.

The general view was, that the embryo originated in the ovule, which was in some obscure manner fertilized by the pollen.

C. Treviranus, professor of botany in Bonn, roused the attention of botanists to the development of the embryo, but although he made valuable researches, he did not add much in the way of new information.

The whole subject of fertilization and development of the embryo has been more recently investigated with great assiduity and zeal, as regards both cryptogamous and phanerogamous plants, and details must be sought in the various special articles.

After the gastrula stage, which is found as a developmental stage in all Enterozoa, the embryo of the Hydrozoa proceeds to develop characters which are peculiar to the Coelen- a terata only.

The internal structural differences are even more characteristic. In the hydropolyp the blastopore of the embryo forms the adult mouth situated at the extremity of the hypostome, and the ectoderm and FIG.

Great apparent differences may also be brought about by variations in the period at which the embryo is set free as a larva, and since two free-swimming stages, planula and actinula, are unnecessary, one or other of them is always suppressed.

In Cordylophora the embryo is set free at the parenchymula stage as a planula which fixes itself and develops into a polyp, both gastrula and actinula stages being suppressed.

The embryo passes through three stages - (I) still enclosed within the egg and living on its own yolk; (2) free, within the vitelline mass, which is directly swallowed by the mouth; (3) there is no more vitelline mass, but the embryo is possessed of long external gills, which serve for an exchange of nutritive fluid through the maternal uterus, these gills functioning in the same way as the chorionic villi of the mammalian egg.

Many lizards, however, retain the eggs in the oviducts until the embryo is fully developed; these species then bring forth living young and are called ovo-viviparous by purists.

Flowering plants bear a seed containing an embryo, with usually one or two cotyledons, or seed-leaves; while in flowerless plants there is no seed and therefore no true cotyledon.

The embryo of the taenia echinococcus finds its way from the stomach or intestine into a vein passing to the liver, and, settling itself in the liver, causes so much disturbance there that a capsule of inflammatory material forms around it.

Inside this wall is the special covering of the embryo which shortly becomes distended with clear hydatid fluid.

The embryo is now ec, Ectoderm.

The embryo has be found here in thousands in the increased in size by accumulasummer and autumn months.

It must, of course, be understood that the germinal epithelium covering the ridge, and the mesenchyme inside it, are both derived from the mesoderm or middle layer of the embryo.

In the Dibranchia true nephridia have not been detected in the embryo, nor has it been shown that the genital ducts are derived from the renal tubes.

The blastopore, together with the whole embryo, now elongates.

The external form of the embryo meanwhile passes through highly characteristic changes, which are on the whole fairly constant ara (After Lankester, 17.) FIG.

A circlet of cilia forms when the embryo is still nearly spherical in an equatorial position.

The embryo generally fills the seed, and the cotyledons are rolled or folded on each other.

The reproduction of the higher plants takes place either asexually by the formation of buds or organs answering thereto, or sexually by the production of an embryo plant within the seed.

Germination is often slower where there is a store of available food in the perisperm, or in the endosperm, or in the embryo itself, than where this is scanty or wanting.

A large distinct leafy embryo lies in the middle of a dense, oily tissue (endosperm).

By the development of a ciliated ring just in front of the mouth the embryo becomes a trochosphere.

In other species the infection occurs through the style of the flower, but the fungus after reaching the ovule develops no further during that year but remains dormant in the embryo of the seed.

The development of the embryo within the egg takes about three weeks.

The resemblance of Dinophilus to the Rotifera is, however, quite superficial, and the general structure of this genus with distinct traces of segmentation, especially in the embryo, points to its close affinity, if not to Polygordius in particular, at all events to the Annelida.

The greatest merit of this book is the use of the number of cotyledons as a basis of classification; though it must be remembered that the difference between the monocotyledonous and dicotyledonous embryo was detected by Nehemiah Grew.

This remarkable double fertilization as it has been called, although only recently discovered, has been proved to take place in widely-separated families, and both in Monocotyledons and Dicotyledons, and there is every probability that, perhaps with variations, it is the normal process in Angiosperms. After impregnation the fertilized oosphere immediately surrounds itself with a cell-wall and becomes the oospore which by a process of growth forms the embryo of the new plant.

The endosperm-nucleus divides rapidly to produce a cellular tissue which fills up the interior of the rapidly-growing embryosac, and forms a tissue, known as endosperm, in which is stored a supply of nourishment for the use later on of the embryo.

If, on the other hand, the endosperm is the product of an act of fertilization as definite as that giving rise to the embryo itself, we have to recognize that twin-plants are produced within the embryo-sac - one, the embryo, which becomes the angiospermous plant, the other, the endosperm, a short-lived, undifferentiated nurse to assist in the nutrition of the former, even as the subsidiary embryos in a pluri-embryonic Gymnosperm may facilitate the nutrition of the dominant one.

If this is so, and the endosperm like the embryo is normally the product of a sexual act, hybridization will give a hybrid endosperm as it does a hybrid embryo, and herein (it is suggested) we may have the explanation of the phenomenon of xenia observed in the mixed endosperms of hybrid races of maize and other plants, regarding which it has only been possible hitherto to assert that they were indications of the extension of the influence of the pollen beyond the egg and its product.

The antipodal cells aid more or less in the process of nutrition of the developing embryo, and may undergo multiplication, though they ultimately disintegrate, as do also the synergidae.

In Dicotyledons the shoot of the embryo is wholly derived from the terminal cell of the pro-embryo, from the next cell the root arises, and the remaining ones form the suspensor.

In many Monocotyledons the terminal cell forms the cotyledonary portion alone of the shoot of the embryo, its axial part and the root being derived from the adjacent cell; the cotyledon is thus a terminal structure and the apex of the primary stem a lateral one - a condition in marked contrast with that of the Dicotyledons.

The developing embryo at the end of the suspensor grows out to a varying extent into the forming endosperm, from which by surface absorption it derives good material for growth; at the same time the suspensor plays a direct part as a carrier of nutrition, and may even develop, where perhaps no endosperm is formed, special absorptive "suspensor roots" which invest the developing embryo, or pass out into the body and coats of the ovule, or even into the placenta.

As the embryo develops it may absorb all the food material available, and store, either in its cotyledons or in its hypocotyl, what is not immediately required for growth, as reserve-food for use in germination, and by so doing it increases in size until it may fill entirely the embryo-sac; or its absorptive power at this stage may be limited to what is necessary for growth and it remains of relatively small size, occupying but a small area of the embryo-sac, which is otherwise filled with endosperm in which the reserve-food is stored.

The position of the embryo in relation to the endosperm varies, sometimes it is internal, sometimes external, but the significance of this has not yet been established.

Its segmentation always begins before that of the egg, and thus there is timely preparation for the nursing of the young embryo.

If in its extension to contain the new formations within it the embryo-sac remains narrow, endosperm formation proceeds upon the lines of a cell-division, but in wide embryo-sacs the endosperm is first of all formed as a layer of naked cells around the wall of the sac, and only gradually acquires a pluricellular character, forming a tissue filling the sac. The function of the endosperm is primarily that of nourishing the embryo, and its basal position in the embryo-sac places it favourably for the absorption of food material entering the ovule.

It may be wholly absorbed by the progressive growth of the embryo within the embryo-sac, or it may persist as a definite and more or less conspicuous constituent of the seed.

In cases where the embryo has stored reserve food within itself and thus provided for self-nutrition, such endosperm as remains in the seed may take on other functions, for instance, that of water-absorption.

Parthenogenesis, or the development of an embryo from an egg-cell without the latter having been fertilized has been described in species of Thalictrum, Antennaria and Alchemilla.

Isolated cases show that any of the cells within the embryo-sac may exceptionally form an embryo, e.g.

In two Malayan species of Balanophora, the embryo is developed from a cell of the endosperm, which is formed from the upper polar nucleus only, the egg apparatus becoming disorganized.

As the development of embryo and endosperm proceeds within the embryo-sac, its wall enlarges and commonly absorbs the substance of the nucellus (which is likewise enlarging) to near its outer limit, and combines with it and the integument Fruit and to form the seed-coat; or the whole nucellus and even the integument may be absorbed.

The presence or absence of endosperm, its relative amount when present, and the position of the embryo within it, are valuable characters for the distinction of orders and groups of orders.

Their function is the twofold one of protecting the embryo and of aiding in dissemination; they may also directly promote germination.

If the fruit is a dehiscent one and the seed is therefore soon exposed, the seed-coat has to provide for the protection of the embryo and may also have to secure dissemination.

On the other hand, indehiscent fruits discharge these functions for the embryo, and the seed-coat is only slightly developed.

Their fortuitous dissemination does not always bring seeds upon a suitable nidus for germination, the primary essential of which is a sufficiency of moisture, and the duration of vitality of the embryo is a point of interest.

This pause, often of so long duration, in the growth of the embryo between the time of its perfect development within the seed and the moment of germination, is one of the remarkable and distinctive features of the life of Spermatophytes.

The aim of germination is the fixing of the embryo in the soil, effected usually by means of the root, which is the first part of the embryo to appear, in preparation for the elongation of the epicotyledonary portion of the shoot, and there is infinite variety in the details of the process.

In albuminous Monocotyledons the cotyledon itself, probably in consequence of its terminal position, is commonly the agent by which the embryo is thrust out of the seed, and it may function solely as a feeder, its extremity developing as a sucker through which the endosperm is absorbed, or it may become the first green organ, the terminal sucker dropping off with the seed-coat when the endosperm is exhausted.

When the cells of the morula stage of an embryo are shaken asunder, each, instead of forming the appropriate part of a single organism, may form a complete new organism.

A slight change in the structure or activity of a gland, by altering the internal secretion, may produce widespread alterations even in an adult organism; and we have good reason to suppose that, if compatible with viability, such minute changes would have even a greater ultimate effect if they occurred in an embryo.

In England, after receiving such modifications - attributed to Burke - as adapted it to the purposes of the opposition, this pamphlet ran through many editions, and procured for its author, as he said, "the honour of having his name inserted in a long list of proscriptions enrolled in a bill of attainder commenced in one of the two houses of parliament, but suppressed in embryo by the hasty course of events."

Symmetrical at their first appearance in the embryo, the somites (from which the myotomes are derived) early undergo a certain distortion, the effect of which is to carry the somites of the left side forwards through the length of one half-segment.

The embryo now consists of two layers of cells, epiblast and hypoblast, surrounding a cavity, the archenteron, which opens to the exterior by the orifice of invagination or blastopore.

After invagination is completed, the embryo begins to elongate, the blastopore becomes narrower, and the dorsal wall of the gastrula loses its convexity, and becomes flattened to form the dorsal plate, the outer layer of which is the primordium of the neurochord and the inner layer the primordium of the notochord.

About the eighth hour after commencement of development the membrane ruptures and the oval embryo escapes, swimming by means of its flagella at the surface of the sea for another twenty-four hours, during which the principal organs are laid down, although the mouth does not open until the close of this period.

In this genus alone of the known Sympoda the eyes sometimes form a pair, in accordance with the custom of all other malacostracan orders except this and of this order itself in the embryo (Sars, 1900).

Brown's views as to the structure of the unimpregnated ovule (with the introduction of the term "sac embryonnaire"); and in that it shows how nearly Brongniart anticipated Amici's subsequent (1846) discovery of the entrance of the pollen-tube into the micropyle, fertilizing the female cell which then develops into the embryo.

Cleavage leads to the formation of an epibolic gastrula and ciliated embryo which hatches as a free-swimming larva remarkably like that of a Polychaete worm (D).

The position of the embryo is plainly visible on the front side at the base of the grain.

The embryo presents many points of interest.

The scutellum meanwhile feeds the developing embryo from the endosperm.

The persistent bracts (glume and pale) afford an additional protection to the fruit; they protect the embryo, which is near the surface, from too rapid wetting and, when once soaked, from drying up again.

Seeds albuminous, with one integument; the single embryo, usually bearing two partially fused cotyledons, is attached to a long tangled suspensor.

After fertilization the ovum-nucleus divides and cell-formation proceeds rapidly, especially in the lower part of the ovum, in which the cotyledon and axis of the embryo are differentiated; the long, tangled suspensor of the cycadean embryo is not found in Ginkgo.

The structure of the seed, the presence of two neck-cells in the archegonia, the late development of the embryo, the partially-fused cotyledons and certain anatomical characters, are features common to Ginkgo and the cycads.

In the Abietineae the cells of the middle tier elongate and push the lowest tier deeper into the endosperm; the cells of the bottom tier may remain in lateral contact and produce together one embryo, or they may separate (Pinus, Juniperus, &c.) and form four potential embryos.

The ripe albuminous seed contains a single embryo with two or more cotyledons.

In Ephedra helvetica, as described by Jaccard, no proembryo or suspensor is formed; but the most vigorous fertilized egg, after undergoing several divisions, becomes attached to a tissue, termed the columella, which serves the purpose of a primary suspensor; the columella appears to be formed by the lignification of certain cells in the central region of the embryo-sac. At a later stage some of the cells in the upper (micropylar) end of the embryo divide and undergo considerable elongation, serving the purpose of a secondary suspensor.

One embryo only comes to maturity.

The embryo of Gnetum forms an out-growth from the hypocotyl, which serves as a feeder and draws nourishment from the prothallus.

A ring-shaped plate of calcite, secreted by the ectoderm, is then formed, lying between the embryo and the surface of attachment.

The early segmentation of the embryo differs in the several groups, but usually the first leaf or leaves, the apex of the stem and the first root are differentiated early, while a special absorbent organ (the foot) maintains for some time the physiological connexion between the sporophyte and the prothallus.

The half of the embryo directed towards the archegonial neck gives rise to the apex of the stem and a sheath of three leaves, the, other half to the small foot and the primary root.

After fertilization the embryo forms a short suspensor; the apex of the stem, with a leaf on each side of it, is first distinguishable; at the base of this is the foot; while the root arises on the farther side of the latter.

Important points of difference are found in the multiciliate spermatozoids, and in the embryo, which has no suspensor.

In Peripatus the prostomium of the Chaetopod-like ancestor is atrophied, but it is possible that two processes on the front of the head (FP) represent in the embryo the dwindled prostomial tentacles.

The three prosthomeres or prae-oral somites of Crustacea due to the sinking back of the mouth one somite farther than in Arachnida are not clearly indicated by coelomic cavities in the embryo, but their existence is clearly established by the development and position of the appendages and by the neuromeres.

Three neuromeresa proto-, deutero-, and trito-cerebrum - corresponding to those three prosthomeres are sharply marked in the embryo.

It appears from observation of the embryo that whilst the first prosthomere of Centipedes has its appendages reduced and represented only by eye-patches (as in Arachnida, Crustacea and Hexapoda), the second has a rudimentary antenna, which disappears, whilst the third carries the permanent antennae, which accordingly correspond to the second antennae of Crustacea, and are absent in Hexapoda.

The somites of the abdomen all may carry rudimentary appendages in the embryo, and some of the hinder somites may retain their appendages in a modified form in adult life.

The seeds contain a large embryo and no endosperm.

C, Ventral view of embryo with three pairs of mesoblastic somites, dumb-bell shaped blastopore and primitive s t r e a k.

D, Ventral view of embryo, in which the blastopore has completely closed in its middle portion.

For an account of the further development of the megaspore, and the formation of the egg-cell, from which after fertilization is formed the embryo, see Gymnosperms and Angiosperms.

Consequent upon this, after a longer or shorter period, those changes commence in the embryo-sac which result in the formation of the embryo plant, the ovule also undergoing changes which convert it into the seed, and fit it for a protective covering, and a store of nutriment for the embryo.

The vegetable oils and fats occur chiefly in the seeds, where they are stored to nourish the embryo, whereas in animals the oils and fats are enclosed mainly in the cellular tissues of the intestines and of the back.

It is a curious fact that in no case has an embryo been found in any of these seeds; probably fertilization took place after they were shed, and was followed immediately by germination.

I I, Bennettites seed in longitudinal section, showing the dicotyledonous embryo; p, cotyledons; r, radicle; s, testa.

Development and Metamorphosis.-In a great number of batrachians, including most of the European species, the egg is small and the food-yolk is in insufficient quantity to form an external appendage of the embryo.

It was suggested that universal abhorrence at experimentation would be felt if the embryo was regarded as " human " .

Front and back At six days old, the embryo, now called a blastocyst, consists of only a few hundred cells.

He compares the tube heart of an embryo to that of the primitive chordate, Amphioxus.

He supports the use of the human embryo for experiments and the production of the embryonic human clone for the same purpose.

Expansion of the extra-embryonic coelom cavity allows the yolk sac and allantois to expand into the coelom cavity allows the yolk sac and allantois to expand into the coelom cavity from the gut of the embryo.

The " Folders " section covers a number of bioethical topics, including embryo research, stem cells, cloning, and pre-implantation diagnosis.

Tides have a vital role to play in the formation of embryo dunes, by depositing tidal litter.

The first cells of this sort to form in the embryo are called the ectoderm, the mesoderm and the endoderm.

A cloned human embryo is created in both cases.

Proteins in the growing ridge (dark band) of a limb bud in a chick embryo.

The rats will be humanely killed to supply serum, which is essential for the in vitro culture of mouse embryo tissues.

It is possible to remove cells from early pre-implantation embryos without damage to the original embryo.

Even the Warnock Committee had a minority report which regarded the human embryo as unsuitable for destructive experimentation.

Thus abortion, the " morning after " pill and embryo experimentation remain illegal, but the " x " case exception still stands.

Budding of Rous sarcoma virus and vesicular stomatitis virus from localized lipid regions in the plasma membrane of chicken embryo fibroblasts.

But surprisingly, mice embryo fibroblasts (MEFs) derived from these embryos proliferated normally and ERK activation was also completely normal.

In flowering plants, anther s produce pollen which contains male gametes, and the embryo sac within the ovary contains a female gamete.

The embryo has also been subject to linguistic gymnastics.

You consider the Gnostic heresy that is here in embryo in this book.

Embryo research will always remain morally impermissible for a large section of the population.

The early embryo is not in able to make informed consent in plans concerning its own future.

Further developments in DNA technology now allow technicians to determine a pre- implantation embryo ' s histocompatibility leukocyte antigen (HLA ).

Pregnancies and deliveries after in vitro maturation culture followed by in vitro fertilization and embryo transfer without stimulation in women with polycystic ovary syndrome.

Mr Paul Szabo MP has called for an indefinite moratorium on embryo research.

A tiny embryo is aware, even before the central nervous system is formed.

Just like a leech derives nourishment from its host's blood, the embryo derives nourishment from the decidua or the pregnant endometrium.

Sunday Post Quiz Answers, June 8, 2003 1 To provide nourishment for the bird or animal embryo.

A cloned embryo is created by cell nuclear transfer from an adult cell into an enucleated oocyte.

It was unfortunate that the definition of an embryo in the HFEA overlooked that cloning could be done using an unfertilised ovum.

Human cloning produces an embryo by fusing the nucleus of a body cell with an enucleated ovum.

The initial segmentation of the embryo is dependent upon concentration biases in the fertilized egg.

The brine shrimp embryo also requires less energy to break through a hatching membrane than a thick outer shell.

Mr Slope, great as he was with embryo grandeur, still came to see the signora.

The HFEA will not license research projects involving embryo splitting with the intention of increasing the number of embryos for transfer.

These procedures are utilized in somatic cell nuclear transfer (SCNT ), a type of embryo stem cell research, and in IVF.

Excess non-protein nitrogen in the form of dietary urea reduced embryo quality.

One of the sperm fuses with egg to form a single cell called a zygote, which then starts dividing and becomes an embryo.

The fruit is berry-like, and the seeds are remarkable for having their embryo surrounded by an endosperm as well as by a perisperm.

The vast majority of the mammalia are provided with an organ in the uterus, by which, before the birth of their young, a vascular connexion is maintained between the embryo and the parent animal.

This theory of Brahma being born from a golden egg is, however, a mere adaptation of the Vedic conception of Hiranya-garbha (" golden embryo"), who is represented as the supreme god in a hymn of the tenth (and last) book of the Rigveda.

There is no free-swimming planula larva, but the stage corresponding to it is passed over in an enveloping cyst, which is secreted round the embryo by its own ectodermal layer, shortly after the germ-layer formation is complete, i.e.

Protected by the double envelope, the embryo is set free as a so-called " egg," and in Europe it passes the winter in this condition.

In the spring the embryo bursts its shell and is set free as a minute actinula which becomes a Hydra.

The embryo is generally surrounded by a larger or smaller amount of foodstuff (endosperm) which serves to nourish it in its development to form a seedling when the seed germinates; frequently, however, as in pea or bean and their allies, the whole of the nourishment for future use is stored up in the cotyledons themselves, which then become thick and fleshy.

Protected between the cotyledons and terminating the axis of the plant is the first stem-bud (the plumule of the embryo), by the further growth and development of which the aerial portion of the plant, consisting of stem, leaves and branches, is formed, while the development of the radicle forms the root-system.

Vezhdovsky to exist in the embryo of certain forms. The blood in the Chaetopoda consists of a plasma in which float a few corpuscles.

But in these epibolic forms, just as in the embolic Paludina, the embryo proceeds to develop its ciliated band and shellgland, passing through the earlier condition of a trochosphere to that of the veliger.

On this view Wheeler, however, compares with the " dorsal organ " the peculiar the entire food-canal in most Hexapoda must be regarded as of extra embryonic membrane or indusium which he has observed ectodermal origin, the " endoblast " represents mesoderm only, between serosa and amnion in the embryo of the grasshopper and the median furrow whence it arises can be no longer compared Xiphidium.

One view, the monozoic, regards the whole development as a prolonged metamorphosis; another, the polyzoic view, considers that not only is the Cestode a colony, the proglottides being produced asexually, but that the scolex which buds off these individuals is itself a bud produced by the spherical embryo or onchosphere.

The result of this process is a minute ovoid embryo consisting of a solid mass of cells surrounded by a follicle of flattened yolk-cells.

On the news of the battle (coupled with that of a fresh army appearing on the Korean coast),' Kuropatkin instantly sent off part of his embryo central mass to bar the mountain passes of Fenshuiling and Motienling against the imagined relentless pursuit of the victors, and prepared to shift his centre of concentration back to Mukden.

In some plants the nucellus is not thus absorbed, but itself becomes a seat of deposit of reserve-food constituting the perisperm which may coexist with endosperm, as in the water-lily order, or may alone form a food-reserve for the embryo, as in Canna.

Recent investigations (Folsom, 4) show the existence in the embryo of a prae-maxillary or supra-lingual somite which is suppressed during development.

Allowing embryo research in the UK to include the investigation of regenerative cell therapies will pave the way for treatments for hitherto incurable diseases.

By the sixth week of pregnancy the embryo is already encased in an amniotic sac of fluid.

These procedures are utilized in somatic cell nuclear transfer (SCNT), a type of embryo stem cell research, and in IVF.

Dolly, the lamb born from the test-tube embryo, is an identical twin of the " parent " ewe that donated the cell.

Remember that incubator thermometer readings will not be the same as embryo temperatures when cooling or heating occurs.

Nevertheless, some mice will be operated on during the embryo transfer and vasectomy procedures but these operations will be performed under general anesthesia.

I saw the face of an embryo with large, wide-open eyes.

All the nutrients required for embryo development are already present within the fertilized egg, stored in the form of yolk protein molecules.

The most likely explanation for this phenomenon is that a cat with two faces is actually the result of a protein that disrupts embryo development.

Identical twins represent the splitting of a single fertilized zygote (union of two gametes or male/female sex cells to produce a developing embryo) into two separate individuals.

Their use is controversial because such stem cells cannot be used in research without destroying the living embryo.

Teratogen-Any drug, chemical, maternal disease, or exposure that can cause physical or functional defects in an exposed embryo or fetus.

Urogenital-Refers to both the urinary system and the sexual organs, which form together in the developing embryo.

Birth defects can result from the variation in a woman's blood sugar level during the first eight to 12 weeks, which is the time period when the embryo is developing.

Between 10 and 14 weeks of pregnancy, physicians may use an ultrasound to look for a thickness at the nuchal translucency, a pocket of fluid in back of the embryo's neck, which may indicate a cardiac defect in 55 percent of cases.

The neural tube of the embryo develops into the brain, spinal cord, spinal column, and the skull.

Studying prenatal human development is difficult because the embryo and fetus develop in a closed environment-the mother's womb.

Until the end of the eighth week the developing organism is called an embryo.

During the first eight weeks of pregnancy, organogenesis (the formation of organs) is taking place, which places the embryo at a higher risk of deformities when exposed to teratogens.

In the first stage, four to 20 weeks gestation, rapid cell division and multiplication (hyperplasia) occurs as the embryo grows into a fetus.

Preimplantation genetic diagnosis (PGD) is a relatively new technique that involves in-vitro fertilization followed by genetic testing of one cell from each developing embryo.

Sometimes a child may end up with more than 46 chromosomes because of problems with the father's sperm or the mother's egg or because of mutations that occurred after the sperm and the egg fused to form the embryo (conception).

A condition called trisomy occurs when three, instead of two, copies of a chromosome are present in a developing human embryo.

The most well-known trisomy-related disorder is Down syndrome (trisomy 21), in which the developing embryo has an extra copy of chromosome 21.

Patau syndrome is trisomy 13, in which the developing embryo has three copies of chromosome 13.

Most girls with Turner syndrome do not have ovaries with healthy oocytes capable of fertilization and embryo formation.

Prenatal development refers to the process in which a baby develops from a single cell after conception into an embryo and later a fetus.

As the embryo develops, each germ layer differentiates into different tissues and structures.

The embryo is now referred to as a fetus.

When an embryo becomes a fetus at eight weeks, it is approximately 3 centimeters (1.2 inches) in length from crown to rump and weighs about 3 grams (0.1 ounce).

The age, health status, nutritional status, and environment of the mother are all closely tied to the health of a growing embryo or fetus.

Purified chick embryo cell (PCEC) vaccine became available in the United States in 1997.

Purified chicken embryo cell vaccine (PCEC)-A rabies vaccine in which the virus is grown in cultures of chicken embryo cells, inactivated, and purified for IM injection.

Iodine is needed to make thyroid hormone, which has a variety of roles in human embryo development.

Congenital brain defects may be caused by inherited genetic defects, spontaneous mutations within the genes of the embryo, or effects on the embryo due to the mother's infection, trauma, or drug use.

An autosomal dominant form of VWD can be inherited from either parent or can occur as a spontaneous gene mutation (change) in the embryo that is formed when the egg and sperm cells come together during fertilization.

By the end of the fifth week, the embryo has doubled in size and has grown a tail-like structure that becomes the coccyx (lowermost tip of the backbone).

By the seventh week the embryo is about 2 cm (1 in) long and facial features are visible.

Androgens regulate the development of the embryo, determining whether it is a male or a female (male in the presence of androgens and female in the absence of androgens).

Female is the default sex of the embryo, so most of the sex organ deficits at birth occur in boys.

The error that causes the extra Y chromosome can occur in the fertilizing sperm or in the developing embryo.

It is awe inspiring as you marvel at the beauty of a flower, the magnificence of the pyramids or the miracle of the growth of a human embryo.

When a baby is conceived and the human embryo begins to grow, the spine begins to unfold.

The embryo is about a quarter of an inch long at the end of the first month and has little bumps where his or her arms and legs will later develop.

By the end of the second month, the embryo has grown to about one and a half inches.

A lot of focus in the second month of prenatal development is on the brain, so if you saw a embryo during this stage it would have a very big forehead compared to the size of the rest of the embryo.

One woman from the study had her embryo thawed and used a surrogate.

Another woman (the Letrozol group), however, completed an embryo transfer and gave birth to a healthy baby.

Once fertilization occurs, however, the embryo is at risk.

Embryo preservation is the preferred method, as eggs can be more fragile.

The embryonic age is the age of the embryo from the time of fertilization.

An early pregnancy discharge could also be a sign of an ectopic pregnancy, which occurs when the embryo implants itself outside of the womb.

The ectopic pregnancy is possible because the medical team placed the placenta and embryo into the man's abdominal cavity.

During in vitro fertilization, the gender of each embryo can be determined in advance of having them implanted in the uterus.

Since the embryo's DNA is analyzed, this method has the highest chances of producing a girl.

After the fertilization occurs, physicians can determine the sex of the embryo even before it's implanted.

Implantation bleeding occurs when the embryo implants itself into the wall of the uterus.

They may also have some implantation bleeding from when the embryo attaches to the wall of the uterus.

Conception occurs when a sperm fertilizes the egg, creating an embryo that attaches to the uterine wall.

Research continues to look at genetics and the developing chromosomes of the human embryo in hopes of reducing the number of incidences where alterations in chromosomes occur during and after fertilization.

While a normal pregnancy involves an embryo implanted inside the uterus and growing into a fetus there, pregnancies outside of the uterus are always miscarried, due to insufficient space for the baby to grow.

The only clear diagnosis of ectopic pregnancy is seeing the embryo implanted in the fallopian tube or some other area outside the uterus.

The gender of the embryo is selected and implanted.

This hormone starts changing the embryo into a fetus while it also begins to cause changes in the mother's body as well.

The short embryo transfer procedure is the core of the infertility treatment.

Pregnancy tests can begin two weeks after the embryo transfer procedure.

The doctor conducts an ultrasound about two weeks after the confirmed pregnancy to ensure that the embryo is developing normally.

Human embryo development is a fascinating topic that many expecting moms explore.

Discover how a baby develops in the womb and learn about changes that take place as a fertilized egg develops into a cluster of cells that gradually form an embryo.

Conception is the beginning of human embryo development.

The National Institutes of Health's Medline Plus describes two stages an egg cell goes through before becoming an embryo.

The inner cells gradually develop into an embryo.

The cells in the blastocyst continue to divide and grow to form an embryo.

Differentiation occurs during the first trimester and it is a very important time of the embryo's development.

In addition to differentiation, human embryo development in the first trimester includes major developments in different parts of the body's systems.

The heart begins to develop in the embryo and begins to beat regularly.

The structures are not fully developed in an embryo, but they are forming rapidly as they become ready for the next stage.

Many important changes occur as the developing baby grows from a cluster of cells to an embryo.

The fetal period is an exciting time because the embryo has transformed into a fetus that gradually develops into a baby.

These devices cause changes that make it difficult for the fertilization of an egg or implantation of an embryo to occur.

You may feel cramps when the embryo implants in the uterus, and they can continue intermittently as your uterus expands.

The reason we hear about this vitamin so often is that it is a vital in the diet of women who plan to get pregnant or who are already pregnant for proper development of the embryo.

Fans were outraged when scribes altered her 1970's abortion by retroactively saying the embryo was stolen and implanted in another woman, but Susan's portrayal remained as graceful as ever.

All the way back in 1902, scientist and embryologist Hans Spemman, meticulously sliced a 2-celled salamander embryo by using a single hair from his infant son's head.

Later he separated one single cell from a 16-celled embryo.

The female gametophyte is extremely reduced; there is a sexual apparatus of naked cells, one of which is the egg-cell which, after fusion with a male cell, divides to form a large siispensorial cell and a terminal embryo.

In moths and certain saw-flies there is no rupture of the membranes; the Russian zoologists Tichomirov and Kovalevsky have described the growth of both amnion and embryonic ectoderm around the yolk, the embryo being thus completely enclosed until hatching time by both amnion and serosa.

In the cockroach embryo, before the segmentation of the germ-band has begun, the primitive germ-cells can be recognized at the hinder end of the mesoderm, from whose ordinary cells they can be distinguished by their larger size.

The presence of rudiments of the genital ducts of both sexes in the embryo of either sex is interesting and suggestive.

Hence we are inclined to look on the imaginal disks as cellular areas that possess in a latent condition the powers of growth and development that exist in the embryo, powers that only become evident in certain special conditions of the organism.

In the egg of these insects a small number of nuclei are formed by the division of the nucleus, and each of these nuclei originates by division the cell-layers of a separate embryo.

Aristotle and Harvey (De generatione animalium, 1651) had considered the insect larva as a prematurely hatched embryo and the pupa as a second egg.

In the embryo, however, what have been regarded as remnants of limbs may be seen.

The embryo thus passes from the body of the female into the alimentary canal of the host and leaves this with the faeces.

In the subdivision of the order into tribes use is made of differences in the form of the fruit and the manner of folding of the embryo.

But on the 19th of May 1841 he preached at Boston a sermon on "the transient and permanent in Christianity," which presented in embryo the main principles and ideas of his final theological position, and the preaching of which determined his subsequent relations to the churches with which he was connected and to the whole ecclesiastical world.

In 1893, some years after the identification of the somites of Limulus with those of Scorpio, thus indicated, had been published, zoologists were startled by the discovery by a Japanese zoologist, Kishinouye (8), of a seventh prosomatic somite in the embryo of Limulus longispina.

In the case of Scorpio this segment is indicated in the embryo by the presence of a pair of rudimentary appendages, carried by a well-marked somite.

Previously to this, Lankester's pupil Gulland had shown (1885) that in the embryo the coxal gland is a comparatively simple tube, which opens to the exterior in this position and by its other extremity into a coelomic space.

Then we have Beard's " germ-cell " hypothesis, in which he holds that many of the germ-cells in the growing embryo fail to reach their proper position - the generative areas - and settle down and become quiescent in some somatic tissue of the embryo.

The testa is thin and membranous but occasionally coloured, and the embryo small, the great bulk of the seed being occupied by the hard farinaceous endosperm (albumen) on which the nutritive value of the grain depends.

In the case of the great grey kangaroo, for instance, the period of gestation is less than forty days, and the newly-born embryo, which is blind, naked, and unable to use its bud-like limbs, is little more than an inch in length.

Such cannulated cells are characteristic of the nephridia of many worms, and the organs thus formed in the embryo Limnaeus are embryonic nephridia.

The body thus formed ment of is called the embryo, and this develops into the adult Primary plant, not by continued growth of all its parts as in an animal, but by localization of the regions of cell-division and growth, such a localized region being called a growing-point.

It is absent in the Ratitae, which from this feature have received their name, but considerable traces of a cartilaginous keel occur in the embryo of the ostrich, showing undeniably that the absence of a keel in the recent bird is not a primitive, fundamental feature.

The foot is always simple, with its flat crawling surface extending from end to end, but in the embryo Limnaea it shows a bilobed character, which leads on to the condition characteristic of Pteropoda.

When the middle and hinder regions of the blastopore are closing in, an equatorial ridge of ciliated cells is formed, converting the embryo into a typical trochosphere.

The embryo consists of an axis bearing two or more cotyledons and ending below in a radicle; it lies in a generally copious food-storing tissue (endosperm) which is the remains of the female prothallus.

If we go back to the first instance cited, the embryo in the seed and its development during germination, we can ascertain what is necessary for its life by inquiring what are the materials which are deposited in the seed, and which become exhausted by consumption as growth and development proceed.

The preconchylian invagination or shell-gland is formed in the embryo behind the velum, on the surface opposite the blastopore.

The Pulmonata have a straight visceral nerve-loop, usually no operculum even in the embryo, and a multidenticulate radula, the teeth being equi-formal; and they are hermaphrodite.

If the three principal organ-systems of the medusa, namely mouth, tentacles and umbrella, be considered in the light of phylogeny, it is evident that the manubrium bearing the mouth must be the oldest, as representing a common property of all the Coelentera, even of the gastrula embryo of all Enterozoa.

When the young sporophyte first begins its independent lifewhen, that is, it exists in the form of the embryo in the seedits living substance has no power of utilizing the simple inorganic compounds spoken of.

If the embryo is set free as a free-swimming, so-called planula-larva, in the blastula, parenchymula, or gastrula stage, then a free actinula stage is not found; if, on the other hand, a free actinula occurs, then there is no free planula stage.

It is not true, for example, that a fish is a reptile arrested in its development, or that a reptile was ever a fish; but it is true that the reptile embryo, at one stage of its development, is an organism which, if it had an independent existence, must be classified among fishes; and all the organs of the reptile pass, in the course of their development, through conditions which are closely analogous to those which are permanent in some fishes.

The female is viviparous, and the young, which, unlike the parent, are provided with a long tail, live free in water; it was formerly believed from the frequency with which the legs and feet were attacked by this parasite that the embryo entered the skin directly from the water, but it has been shown by Fedschenko, and confirmed by Manson, Leiper and others, that the larva bores its way into the body of a Cyclops and there undergoes further development.

The embryo consists of an axis bearing one (Monocotyledons) or two (Dicotyledons) cotyledons, which protect the stem bud (plumule) of the future plant, and ending below in a radicle.

Chun and Woltereck, on the other hand, regard the stem as a stolo prolifer arising from the aboral pole, that is to say, from the ex-umbrella, similar to that which grows out from the ex-umbral surface of the embryo of the Narcomedusae and produces buds, a view which is certainly supported by the embryological evidence to be adduced shortly.

In fact, there is a period when, as Aristotle long ago said, the embryo of the highest animal has the form of a mere worm, and, devoid of internal and external organization, is merely an almost structureless lump of polype-substance.

He showed that all the organs of plants are built up of cells, that the plant embryo originates from a single cell, and that the physiological activities of the plant are dependent upon the individual activities of these vital units.

In germination of the seed the root of the embryo (radicle) grows out to get a holdfast for the plant; this is generally followed by the growth of the short stem immediately above the root, the so-called "hypocotyl," which carries up the cotyledons above the ground, where they spread to the light and become the first green leaves of the plant.

It has been ascertained that the nephridia of Oligochaeta are preceded in the embryo by a pair of delicate and sinuous tubes, also found in the Hirudinea and Polychaeta, which are larval excretory organs.

The external form of the embryo goes through the same changes as in other Gastropods, and is not, as was held previously to Lankester's observations, exceptional.

Later, the axis branches by the formation of new growing-points, and in this way the complex system of axes forming the body of the ordinary vascular plant is built up. In the flowering plants the embryo, after developing up to a certain point, stopf growing and rests, enclosed within the seed.