United States or Bahrain ? Vote for the TOP Country of the Week !
The union usually takes place in the tube. The spermatozoon, after being deposited in the vagina, travels to the mouth of the womb, then up through the womb into one of the tubes. Here it meets the ovum and unites with it, then the impregnated ovum continues on its way to the uterus. It attaches itself to the lining of the womb by little thread-like filaments which it projects.
Almost at the moment when they touch, the two cells unite so intimately that all trace of the spermatozoon is lost. Fertilization of the ovum, as this event is scientifically termed, has as its main purpose the uniting of the nucleus of a male germinal cell with the nucleus of the female germinal cell.
It may be the initial effect; very probably it is; but since the main function of the spermatozoon must be the introduction of germplasm from the male parent, it is too much for anyone to ask us to believe that its main function is concerned with surface alteration.
Sexual reproduction is quite a distinct matter. Here, in all these cases, what is required is the detachment of two portions of the parental organisms, which portions we know as the egg and the spermatozoon. In plants it is the ovule and the pollen-grain, as in the flowering plants, or the ovule and the antherozooid, as in the flowerless.
Word Of The Day