ovarian and uterine cycle -my p

8/3/2019 Ovarian and Uterine Cycle -My p

1/23

The ovarian & uterinecycles

DR. Amany El-AgawanyAss. Prof. of Anatomy


2/23


3/23

THE OVARIAN CYCLE- It is the periodic changes which occur in the

ovary under the control of pituitary

hormones. The duration of each cycle isabout 28 days (23-35).- Ovulation is the most important events of the

ovarian cycle.- It is the release of an ovum from the mature

Graafian follicle which occurs approximatelythe middle of each ovarian cycle.

Phases :

1- the follicular phase : ( pre-ovulatory

phase) Characterized by the growth of

primordial follicle into mature Graafianfollicle under the control of the folliclestimulating hormone ( F.S.H )of thepituitary .

The cells of the developing follicle (theca interna & granulosa cells )secretes oestrogen hormone .

The presence of oestrogen hormonein the ovary at this stage is responsible forthe proliferative phase of the uterinecycle.


4/23

HISTOLOGY OF OVARIAN FOLLICLES


5/23


6/23

If fertilization occurs , corpus luteum is

transformed into corus luteum ofpregnancy and continues to secreteprogesterone .

Now the uterine endometrium istransformed into what is called decidua ofpregnancy to receive the blastocyst,

which reaches the uterine cavity 6 daysafter fertilization .


7/23THE OVARIAN AND MENSTRUAL CYCLE OF THE HUMAN FEMALE


8/23

2- ovulation : This is the main event in

the cycle . The Graafian

follicle grows rapidlyproducing a bulge orcystic swelling on theovarian surface

The Graafian follicleraptures and thesecondary oocyte withfollicular fluid is releasedin the peritoneal cavity.

The oocyte is coveredby the zona pellucidaand the corona radiata.


9/23

Time of ovulation :

The ovulation occurs approximately 14 days(+_ one day) before the beginning of the nextmenstruation regardless of the length of themenstrual cycle .


10/23

3- the luteal phase : It is also called the post ovulatory phase . It is stimulated by L.H of the pituitary , it is characterized

by : This phase occupy the second half of the cycle.

The ruptured follicule changes into corpus luteum. The luteal cells secretes progesterone and estrogen which

suppress secretion of F.S.H. This secreated progesteroneis responsible for the changes which take place in theendometrium in the 2nd half of uterine cycle.


11/23


12/23

Fate of corpus luteum :

Depends on whether fertilization (

pregnancy) occurs or not :1- If fertilization does not occurs :

The corpus luteum lives for 9 days only

after ovulation and then decreases rapidlyin size , degenerates and transformed intomass of fibrous tissue called corpusalbicans .

As the corpus luteum degenerates theprogesterone level in blood decreases somenstruation occurs.


13/23

2- If fertilization occurs : The corpus luteum continues to grow

forming corpus luteum of pregnancy

which lives for 4-5 months and secretsprogesterone hormone until placentabecomes functioning then degenerates.


14/23

OVARIAN CYCLE - OVULATION


15/23

THE UTERINE ( MENSTRUAL) CYCLE This is the periodical changes which occur in

the endometrrium in response to thechanges in the level of the ovarian

hormones.Three phases can recognized in the uterine

cycle:

1- The menstrual phase .

2- The proliferative phase ( post- menstrual).

3- The secretary phase (pre - menstrual) .


16/23


17/23

1- THE MENSTRUAL PHASE

Menstruation is the shedding of the superficiallayer of the endometrium with blood and mucusas vaginal discharge occurring every 28 days.

It is due to degeneration of the corpus luteum at

the luteal phase of the ovarian cycle . It is about 3-5 days.

The blood consists of :

1- venous and arterial blood from degenerated

vessels.2- shedded epithelium of endometrium.

3- Secretions of degenerated uterine glands .


18/23



Now the uterine endometrium istransformed into what is called decidua ofpregnancy to receive the blastocyst,which reaches the uterine cavity 6 daysafter fertilization .


19/23

2-THE PROLIFERATIVE PHASE ( POST-MENSTRUAL) Stimulated by estrogen hormone of the ovary. Repair of endometrium occurs following the

menstruation and increase in endometrialthickening.

It is about 10 days, occurs from 4-14 of thecycle.

The endometrium grows in this stage :

The endometrium becomes 3 mm thick. The uterine glands become longer and

straight like test tube .


20/23

3- THE SECRETARY PHASE (PRE -MENSTRUAL)

Stimulated by progesterone and estrogenhormones .

Occurs from day 14-28 of the period.

The endometrium becomes thicker (5-7 mm)

The uterine glands become more convolutedand full of secretion ( mucus & glycogen)

The spiral arteries become dilated and tortuous.

The endometrium becomes edematous and soft.


21/23


22/23



Now the uterine endometrium istransformed into what is called decidua ofpregnancy to receive the blastocyst,which reaches the uterine cavity 6 daysafter fertilization .


23/23

THE OVARIAN AND MENSTRUAL CYCLE OF THE HUMAN FEMALE

ovarian and uterine cycle -my p

Documents