Oellacher's instances are more valuable, yet sufficient care seems hardly to have been taken, especially when it is not certain for what length of time spermatozoa may be able to live in the oviduct.
The spermatozoa are formed by the breaking up of the male germinal cells, or of cells secondarily derived from them by division.
Fol finds that when the impregnation has been too long delayed the vitelline membrane is formed with comparative slowness, and several spermatozoa are thus enabled to penetrate.
Schulze has found the spermatozoa of this genus of sponge and has been able to shew that the sexes may be distinct, though many species of Halisarca are hermaphrodite.
In Paludina amongst the Mollusca there are two forms of completely developed spermatozoa existing side by side in the same individual.
These groups are the Nematoda and the Crustacea; and the spermatozoa in both of them frequently present very abnormal forms.
The cells which directly give rise by division to the spermatozoa may be called spermospores and are equivalent to the ova or oospores.
In the hermaphrodite forms both ova and spermatozoa are produced in the same pouches (fig.
The development continues, however, to be normal up to the gastrula stage, at any rate, if three or even four spermatozoa enter the egg almost simultaneously.
Although the minute size of most spermatozoa places great difficulties in the way of a satisfactory investigation of them, yet there can be but little doubt that they always have the value of cells.
If at this time the spermatozoa are allowed to come in contact with the egg, their heads soon become enveloped in the investing mucilaginous coat.
The spermatozoa pass through an orifice from the cavity of the testis to the genital capsule, and thence to the spermiduct.
The spermatozoa are no doubt passed into the genital pouch from time to time, and there fertilise the eggs descending from the ovarian tubes.
The convex surface of the chorion is perforated by numerous micropyles, fine pores through which it is probable the spermatozoa gain access to the interior of the egg.
The spermatheca is filled during copulation, and is always found to containspermatozoa in the fertile female.
His reasoning as to the function of the spermatheca wanted nothing but microscopic evidence of the actual transference of spermatozoa to establish it in all points.
By division of the nuclei of the sperm cells spermatozoa are formed, which have at first nucleated heads and long tails.
Composite spermatozoa have been observed with two and three heads and one body and tail-piece, but the significance of these abnormal cells is not known.
The sexual act does not form either thespermatozoa or the ova; these pre-exist.
Only the microscope can tell that the spermatozoa are absent if the fact that he has been vasectomized is not told.
The reduction-division in spermatozoa is similar, but the end process leaves four active spermatozoa, whereas in the ovum the final result is one ovum and three practically inert and cast-off polar bodies.
Although they are not the entire organ of generation, the testicles are together a complete organ in themselves, the function of which is to produce the spermatozoa essential to the procreation of the human species.
There is always doubt that the spermatozoa are present if the microscope is not used, and these canonists all disclaim the use of the microscope in such circumstances.
In such a condition two spermatozoa could fecundate the two nuclei and the development go on as in the case of twins from distinct ova.
There are two essential parts in the semen, the spermatozoa and the carrying liquid.
The human ovum is about half the size of a period in the type of this page, and two hundred and fifty spermatozoa will fit side by side along the horizontal diameter of the lowercase letter o here.
She laid fertile eggs for thirteen years; that is, the spermatozoa in her oviduct retained their vitality for thirteen years.
Muscular peristaltic action presses out the spermatozoa and the secretions of the seminal vesicles and the prostate.
The spermatozoa are always released in a normal sexual act; the ova are not always present when the spermatozoa are released.
The testicles, which the eunuch lacks, have two distinct functions, independent of other organs--they make the spermatozoa and an important internal glandular secretion.
The spermatogenic cycle is completed in the latter half of October when most of the spermatozoa pass into the epididymides.
A few spermatozoa and spermatids remain in the seminiferous tubules during hibernation.
Dewitz, Buller, and the writer have vainly tried to prove the existence of a positive chemotropism of spermatozoa to eggs of the same species.
Loeb and Bancroft made extensive experiments in cultivating spermatozoa of fowl in vitro on suitable culture media.
The first one to recognize the existence of two kinds of spermatozoa was Henking, who stated that in Pyrrhocoris (a Hemipteran) one-half of the spermatozoa of each male possessed a nucleolus, while in the other half it was lacking.
Only when the spermatozoa run against each other with a certain impact will they stick together, as Lillie suggested.
But it happens that of the two types of spermatozoa only one is formed since in one of the cell divisions which lead to the formation of spermatozoa one viable spermatozoon only is formed while the other one perishes.
Assuming it to be true that the chromatin is the important part of the cell in the matter of heredity, then it follows that we have two kinds of spermatozoa that differ from each other in a vital matter.
Unfertilized egg surrounded by spermatozoa (whose flagellum is omitted in the drawing).
A positive chemotropism of the spermatozoa toward an egg of the same species has been demonstrated in a few cases, but it seems that this phenomenon is not determined by that type of substances which give rise to species specificity.
It produces two types of spermatozoawith six and five chromosomes respectively (one-half of the cells losing one chromosome which is left at the line of cleavage between the two cells); and one type with six chromosomes.
The two kinds ofspermatozoa differ in regard to a single chromosome, which is either lacking or different in one-half of the spermatozoa.
Bruchmann[83] found that the spermatozoa of Lycopodium are positively chemotactic to citric acid and salts of this acid, although no citric acid could be shown in the contents of the archegonia.
It also happens at times that when a queen becomes old her supply of spermatozoa is exhausted, at which tune her eggs also develop only into drones.
In mating she receives enough spermatozoa (male sex cells) to last throughout her life.
An opening in the membranes surrounding the ovum, by which nutrition is assisted and the entrance of the spermatozoa permitted.
Defn: An organ in whichspermatozoa are developed; a sperm gland; a testicle.
Bulls with both testicles retained within the abdomen may go through the form of serving a cow, but the service is unfruitful; the spermatozoa are not fully elaborated.
The opinion that the spermatozoa of seminal filaments are real animalculae is now abandoned, but it is held by Dr.
There can be no doubt that it is the contact of the spermatozoa with the ovum, and in the changes which occur as the immediate consequence of that contact, that the act of fecundation essentially consists.
It is essentially necessary for fecundation that the spermatozoa should come into actual contact with the ovum.
In all probability it is, above all, essential, in order that it should occur, that one or morespermatozoa should penetrate the ovum.
At any rate, spermatozoa have been found within the fecundated eggs of the most diverse species of animals.
That the spermatozoa make their way toward the ovarium, and fecundate the ovum either before it entirely quits the ovisac or very shortly afterward," says Dr.
In urine or vaginal discharges these organisms might be mistaken for spermatozoa by one who is entirely unfamiliar with the appearance of either.
Spermatozoa are generally present in the urine of men after nocturnal emissions, after epileptic convulsions, and in spermatorrhea.
The spermatozoa are readily seen with a one-sixth objective (Fig.
As in the species previously described the spermatozoa are evidently dimorphic.
In all of these insects the spermatozoa are distinctly dimorphic, forming two equal classes, one of which either contains one smaller chromosome or lacks one chromosome.
In many cases the spermatozoa of one species will not impregnate the eggs of another species.
For these reasons, ova and spermatozoa can arise only when the germplasm which has been handed on from the original nucleus to certain cells is able to overcome the histogenous plasm of these cells.
Spermatogenesis, the formation of spermatozoa in the testis, 13.
So far as microscopical characters go, egg cells and spermatozoa are wonderfully alike in all the mammalia; in many cases we could not distinguish between those of different animals.
Spermatozoa must not be mistaken for the Trichomonas vaginæ found in the vaginæ of some women.
Several days may elapse before the spermatozoa meet with an ovum and fertilize it.
The protamines are a well-characterized class of albumins found in the ripe spermatozoa of fishes.
In the ova of certain fishes, small openings have been observed through which the spermatozoa find entrance.
The spermatozoado not have time to become maturely developed.
In man, the formation ofspermatozoa continues with greater or less rapidity from puberty to old age, though at the two extremes of existence they are imperfectly developed.
The composition of the nerves and that of spermatozoa is nearly identical.
When the female is about to deposit her eggs, the male mounts upon her back and rides about until the eggs are all deposited, discharging upon them the fertilizing spermatozoa as they are laid by the female.
Spermatozoa originate in the testis as cells, which are filled with granules.
Human spermatozoa are about 1/600 of an inch in length.
The oviducts may have diverticula serving as receptacles for thespermatozoa (in cases where internal impregnation takes place), and may be provided with glands secreting envelopes or shells around the eggs.
The male ducts often have glandular walls, secreting capsules or spermatophores within which the spermatozoa are packed for transference to the female.
The eggs are thus each either male or female and the spermatozoa are indifferent.
The numerical excess of the spermatozoa over the ova in the sea-water is the only guarantee that the eggs are fertilised, for the spermatozoa are carried to the eggs by chance and are not attracted by the latter.
The eggs are indifferent and thespermatozoa are each male, OR female.
The sea-urchin eggs which were fertilised in the laboratory by the spermatozoa of the starfish, as a rule, died earlier than those of the pure breeds.
Spermatozoa were found in the genital vesicle, as well as in the epididymis and its caecum.
On the other hand, if this were not so,--if these spermatozoa were active for a longer period, pregnancy would almost be certain to take place every time the womb was not already occupied with a pregnancy.
When a mother reaches this stage of the wondrous tale she will be asked by an innocent girl,--"How do these spermatozoa get there?
The womb is above the vagina, and the female egg is in the womb, consequently, to reach this egg, the spermatozoamust travel upward.
Leucorrhea or "the whites" may be of such an acid character as to kill the spermatozoa in the vagina, or it may be of such volume as to render impregnation impossible.
When the male semen is deposited in the female vagina, there are thousands of these minute, living, moving spermatozoa in it.
It is by this act that the male spermatozoa is enabled to complete the function of fecundation.
This is proved by the fact that the supernumeraryspermatozoa which sometimes enter the egg do not conjugate with the polar bodies.
Hence the spermatozoa of 1874 must have retained their life and energy for thirteen years, a fact, I believe, unparalleled in physiology.
The males appear at the beginning of July; their spermatozoa are mature in August, and pairing then takes place with certain ‘special females which require fertilization’ which have in the meantime emerged from their cocoons.
In this case an influence might be exerted by these nuclei upon the specific form of the sperm-cells, for the former arise and develope in the form of bundles of spermatozoa in the interior of the mother-cell.
These observations appear however to be erroneous, for Pflüger has since shown that the eggs of frogs never develope if the necessary precautions are taken to prevent the access of anyspermatozoa to the water.
The latter alone possess the power of producing a new colony, and this takes place by the asexual and sexual methods alternately: in the latter a typical fertilization of large egg-cells by small spermatozoa occurs.
In animals it is only known as yet that spermatozoa and ova do attract each other, so that the former find the latter and bore their way through its membranes.
Male discharging thespermatozoa by the breaking up of the ectoderm (ekt); sp spermatozoa; m muscle.
I am here referring to observations made by Carnoy[261] on the cells which form the spermatozoa in various Arthropods.
The recent observations of Born[274] upon the eggs of the frog also make it very probable that a double development is produced by the entrance of two spermatozoa into the egg, but here also only monstrosities, and not twins, were produced.
Among all forms of animal life, the spermatozoa proceed from the male sex, and the egg is the product of the female.
An organ in which spermatozoa are developed; a sperm gland; a testicle.
But in this case the spermatozoa are specially adapted to perform such acts of penetration—being spear-like bodies provided with a sharp point.
Romanes goes on to describe how there may be millions of spermatozoa and “thousands of millions” of their contained “ids” around the ovaries, to which these secondary effects are due.
The tubes through which the spermatozoa pass to effect fertilization, and through which the ova pass from the ovary to the uterus.
Millions of spermatozoa must have been playing around the ovaries after the first copulation, and only one of them was needed to fertilize the mature ovum.
The possibility of any spermatozoa of the first impregnation surviving to take part in the second is excluded by the fact that the phenomenon occurs in mammals, and, apparently, may extend over two or three litters.
It is said that he masturbated on all opportunities and had vigorous erections, although no spermatozoa were found in the semen issued.
The number in which the semen was examined microscopically was 16, and in three spermatozoa were found in the semen; one case was dubious, spermatozoa being found two weeks afterward on a boy's shirt.
Beigel, in Virchow's Archives, mentions a cryptorchid of twenty-two who had nocturnal emissions containing spermatozoa and who indulged in sexual congress.
Spermatozoa have been found days and weeks after castration, and the individuals during this period were capable of impregnation, but in these cases the reservoirs were not empty, although the spring had ceased to flow.
There is little doubt of the possibility of spermatozoa deposited on the genitalia making progress to the seat of fertilization, as their power of motility and tenacity of life have been well demonstrated.
It was alleged that no traces of testicles were found externally or internally yet semen containing spermatozoa was found in the seminal vesicles.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "spermatozoa" in a variety of sentences. We hope that you will now be able to make sentences using this word.
