لطفا منتظر باشید ...
The man-Secure resting place
The process by which the egg settles in
uterus )implantation( is in fact the result
of the interaction between the embryo and
the mother. Therefore , dealing with uterus
transfiguration and also egg cell evolution
after fertilization is essential.
While moving through fallopian tubes,the egg
undergoes a series of mitotic divisions known
as cleavage,as a result of which the number
of cells increase ) the first cell division
takes place 30 hours after fertilization ).
These cells,known as blastomere,get smaller
after each division . As cell division
continues,the egg goes down the oviduct and
when it gets to the 12th to 16th cell steps
it assumes a new name morula )it is so called
because it resembles mulberry up to this step
the egg cell is still enclosed in a hyaline
membrane . Around the 3rd day morula gets to
endometrial cavity.
Uterus wall consists of three layers :
1 - endometrium , or the internal mucous
membrane,2- myometrium,a thick flat muscular
layer,3- perimetrium the lining which covers
the outer portion of the uterus wall.
During the settlement of the egg,the layer of
uterus is in the secretion or progestrone
phase)progestrone is a femal stroid hormone).
At this time uterus glands and arteries
become more meandering and its tissue gets
thick and swollen. Following fertilization
the secretional activity of glands in
endometrium increases and capilaries become
more winding and finally from an intricate
capillary surface exactly under the lower
surface of the uterus . After reaching the
endometrial cavity , morula stays there in
a free state for a few days , during this
period it receives nutrients from the
secretions of the endometrial glands.At the
same time a liquid gathers up in the cell
mass of morula and creates a cavity in it,as
a result of which the cells are divided into
two groups : the one located in the central
parts are called internal cell mass;and the
group located on the peripheral parts are
known as trophoblast ) later , trophoblast
creates placenta and its linings(.During this
stage ) in the 5th and 6th days ( the process
of the settlement begins and trophoblastic
cells penetrate the mucous lining of uterus
with the help of cell division , the action
of enzymes secreted by themselves , and the
readiness of the uterus ) the formation of
the capillary surface under the uterus ).
Gradually and thoroughly these cells gather
under mucous lining of uterus ; little by
little the place they entered endometrium
is repaired.The egg settlement process is
usually completed during the second week
after ovulation.
Generally six days prior to the settlement
process.The egg moves to uterus and settles
in its anterior or the posterior wall ) as
in the processes mentioned (.in case there
is a disturbance in the transfer of the
fertilized egg settlement might not occure
in its normal site.Abnormal settlement of
the fertilized egg away from it normal site
is called out of the womb pregnancy ) ectopic
pregnancy(.Most such pregnancies occur inside
the fallopian tube and generally lead to
abortion.
