Hello! I am Dr Amna Ijaz from medicovisual.com and
today I am going to present you a review lecture on the female reproductive cycle.
Consists of series of monthly cyclical changes in the female body that makes a pregnancy possible.
It consists of two cycles that are going side by side that is uterine cycle and the ovarian cycle.
The average length of the female reproductive cycle is of 28 days.
It can be divided into pre ovulatory, ovulation and post ovulatory phases.
So, under the influence of gonadotropin releasing hormone there is a release of FSH and LH from the
anterior pituitary which causes these primordial follicles to grow from uni-lamellar primary
follicle to Multi-lamillar primary follicle, with the formation of this theca cell around it.
This theca cell secrete testosterone that is converted by this granulosa cell into oestrogen
and there is formation of small fluid filled cavities inside it.
As the follicles are growing we can call it follicular phase of the ovarian cycle.
This follicle is growing in size and it producing more and more oestrogen. So, oestrogen level will
start increasing and what happens in the uterus? In initial days there is bleeding
from the previous cycle that is menstruation and then under the influence of oestrogen
it start proliferating then we can call it proliferative phase of the uterine Cycle.
Then the small fluid filled cavities coalesce to form this antrum and size of the follicle
further increases and it produces more and more oestrogen. So, oestrogen level start rising
due to the rise in oestrogen level there is a slight decline in the level of FSH but
LH level remains unchanged. As the level of oestrogen reaches to its peak
it causes a sudden rise in the level of LH and we call this LH surge.
There is also rise in the FSH that is FSH surge but that is not that much significant. Then
there is ovulation that at about day 14 and this secondary oocyte is released and the remaining
follicle is converted into the yellow progesterone producing body then we call it corpus luteum.
As the corpus luteum is produced we call it luteal phase of the ovarian cycle.
The function of this corpus luteum is to produce large amount of the progesterone.
So, its levels start rising. Progesterone causes three changes in the uterus that is these blood
vessels become engorged and tortures and there is formation of glycogen filled cells and these
glands will become deepened and more torturous and there is a secretion of the uterine milk to meet
the nutritional requirement of coming baby. And we can call it secretory phase of the uterine cycle.
Corpus luteum is producing large amount of progesterone and relatively less amount of
oestrogen and during all these phase level of FSH and LH remain at the Baseline.
But what if pregnancy doesn't occur? This corpus luteum is turned into a white scarred structure
called corpus albicans. As corpus luteum has degenerated the level of progesterone
and oestrogen will fall and there will be slight increase in the level of FSH and
LH to begin the new cycle. And what happens to this uterus that was ready for the baby?
Its wall will shed off and there will be bleeding and the new cycle will start Again.
So, we can see it in a different angle that there is you can see follicular phase of ovarian cycle
and the uterus is proliferating and that is proliferative phase of uterine cycle
then ovulation will occur corpus luteum will be formed and that is luteal phase of ovarian cycle
and uterus is secreting the uterine milk and preparing for the baby and that is secretory
of uterine cycle and if pregnancy doesn't occur corpus albican will be formed and then bleeding
will occur and the cycle will continue. Thank you so much for watching this video.