medicla purpouse

1. By
Sanjay kumar

3. Site for fertilization
Fertilization of ovum occurs in the ampulla or lateral 1/3rd
of uterine tube
Ampulla is longest and widest part of fallopian tube
>fertilization process
take place 24 hr
>it is completed
within 10-16 days of
menstrual cycle

4. Phases of fertilization
1.Aproximation of gamet
2. Contact and fusion of gametes
3 effect of fertilizatin

5. 1. Aproximation of gametes
>200 to 300 milIion of sperm are deposited
in female genital tract
>Only 300 to 500 sperm reach to ampulla .
>Out of these only one sperm will Have to
chance to fertilized to ovum and form
zygote
before undergoing fertilization
The sperm has to undergo some
pre-fertilization changes in spermatozoa
So this pre-fertilization changes include
main Step called as capacitation

6. Capacitation :-
>In female reproductive tract the sperm were
enabled
to bind zona pelucida receptor .the change are
facilitated by removal of Glycoprotien and seminal
plasma protein from plasma membrane of acrosomal
region within the uterine tract.
>It last in 7 hr.

7. 2. Contact and fusion of gametes
During this process three barrier privent the entry
of sperm into the ova
1. corona radiata
2. zona pellucida
3. Vitlline membran of oocyte

8. > 1.Penetration of corona radiata:-
. it is group of cell that is cumulus ovaricus
. This is the 1st berrier
digestted by hyaluronidase
of capacitated sperm
Pass freely through
corona radita

9. 2. Penetration of zona pellucida
-Zona means layer ,
-pellucida means translucent
. It is translucent layer glycoprotein shell surrounding the egg
funtion : facilitates and maintain sprem binding to Zp3
It induces acrosomal reaction

10. Acrosomal reaction:-
It initiated after binding of sperm to zona pellucida
Induced by zonal protein ZP3 that release of acrosomal
enzyme (hyaluronidase acid phosphatase acrosin And
trypsin ) that facilitate pentration of the zona pellucida.
3. VITELLINE MEMBRANE
> The sperm head fuse with vitelline membrane
there two disintigrin protein or peptide carried by the
sperm Head open the gate for the entry of sperm
> The gate is closed by integrin peptide produced by vitellin
Membrane which privent polyspermy

11. 3. Effect of fertilization
 Stimulate the pentrate oocyte to complete its 2nd
meiotic division
> Restorse the normal diploid number of chromosome in
Zygote
 determine the chromosomal sex of the embryo
 initiate the cleavage of zygote
The oocyte finished it 2nd meiotic division immediately
After the entry of spermatozoa one of the daughter cell
which receives hardly any cytoplasm known as 2nd
polar Body .

12. other daughter cell is known as definite oocyte
Chromosome number will be 22+x or +y .
they arrange Them selves vesicular nuclei known as
female pronucleus
The spermatozoa meanwhile most forward until it lies
Close to the female pronucleus .
both fuse and result farmation of zygote
And the fertilisation is completed .