Process of Fertilization Video Lecture - Class 8

fertilization to understand the meaning
of fertilization let us review the
structure of a male gamete or the sperm
and the female gamete or the ovum
observe the diagram shown here entry of
sperm into the oviduct during copulation
or sexual union between the male and the
female the sperms are released in the
vagina of the female near the cervix of
the uterus a single ejaculation of human
nail may contain more than 400 million
sperms the sperms are highly motile they
swim with the help of their tail and
enter the uterus through its opening the
cervix from the cavity of the uterus
they climb upwards to reach the oviduct
out of millions of sperms discharged in
the uterus only a few are able to reach
the upper parts of the oviduct the
remaining died and are absorbed on the
way to oviduct out of the few that
reached the upper part of the oviduct
many surrounds the ovum if it happens to
be there
entry of the sperm in egg the acrosome
of the sperm secretes an enzyme which
digests the wall of the egg to make its
way inside the egg as soon as one sperm
enters the egg the entry of the other
sperms is prevented by some chemical
barrier at this stage the tail of the
sperm is lost within the cytoplasm of
the own the nuclei of the sperm and the
oocyte are called as pronuclei
the male pronucleus containing 22 plus X
or 22 plus y chromosomes fuses with
female pronucleus containing 22 plus X
chromosomes thus restoring the normal
numbers of 23 pairs of chromosomes this
is the actual act or fertilization the
process of union of a haploid
spermatozoon with a haploid own to form
a diploid zygote is called fertilization
the brand-new nucleus formed by the
fusion is diploid and restores the
original number of chromosomes