Ovarian Cycle & Menestrual Cycle

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THE FEMALE REPRODUCTIVE CYCLES

These are the rhythmic changes in the ovary and uterusduring the female fertility period (from 15 45 years).

These cycles occur approximately every 28 days.

They include the menstrual and ovarian cycles

OVARIAN CYCLE

- It is a regular monthly cycle occurring in the ovary

starting at puberty.Stages of the ovarian cycle:

I- The Follicular phase:

Growth of 1ry follicle to mature follicle by FSH


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II. Ovulation = Rupture of the Graffian follicle with liberation of the

secondary oocyte out of the ovary (day 14)


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Factors causing ovulation1- The sharp increase in LH from ant. pituitary.

2- Local weakness and degeneration of the ovarian surface.

3- The increased intrafollicular pressure.

4- Muscular contraction of the ovarian wall.


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III. The Luteal phase (days 15 to 28):


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Fate of corpus luteum

If fertilization does not occur:corpus luteum of menstruation --------------- corpus albicans

If fertilization occurs: corpus luteum of pregnancy


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Oocyte transport1- sweeping movements of the fimbriae of the uterine tube.


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2. In the uterine tube: the oocyte is pushed towards the uterine lumen by

contractions of the muscular wall and the action of the cilia of its mucosa .

(Fertilization takes 24 hours to occur)In human, the fertilized ovum reaches the uterine lumen 3-4 days after

ovulation.


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The Menstrual (Uterine)

Cycle

- It is the cyclic changes occurring in the

endometrium every ~28 days. (menses =months).

- Starts at puberty till menopause.

It is under the control of ovarian hormones.


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Stages


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The menstrual phase (3-5 days):

- No fertilization -----> spasm in the uterinearterioles ---- > cracks and fissures in the

spongy layer of the endometrium - --- >

shedding + haemorrhage.

- Menses occurs 14 days after ovulation.

Contents of the menstrual flow:

- Non-clotted blood

- Desquamated endometrium, cervical

mucus, vaginal cells.


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II. The Follicular (Proliferative) phase (9 days)

- Occurs after the menstrual phase.

- Under control of estrogen secreted by the

Graffian follicle.

The endometrium in thickness (up to 3 mm),

epithelium columnar,

uterine glands --

tortuous & rich ofmucin, glycogen.


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III. The secretory (progestational)

phase (13 days)

- Starts 2-3 days after ovulation.

- Under the effect of progesterone of thecorpus luteum.

- Endometrium --- thick, soft, velvet in nature.- Uterine glands --- more tortuous, full of

mucin, glycogen, and water.

- The ischemic phase: It is day 14 (day 28 of the

whole period) of the secretory phase whereestrogen and progesterone levels fall (due todegeneration of the corpus luteum).


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Ovarian Cycle & Menestrual Cycle