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THE FEMALE REPRODUCTIVE CYCLES These are the rhythmic changes in the ovary and uterus during 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
II. Ovulation = Rupture of the Graffian follicle with liberation of the secondary oocyte out of the ovary (day 14)
Factors causing ovulation
1 -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.
III. The Luteal phase (days 15 to 28):
Fate of corpus luteum
If fertilization does not occur: corpus luteum of menstruation ---------------› corpus
albicans
If fertilization occurs: corpus luteum of pregnancy
Oocyte transport1 -sweeping movements of the fimbriae of the uterine tube.
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.
The Menstrual (Uterine) The Menstrual (Uterine) CycleCycle
- - It is the cyclic changes occurring in the It is the cyclic changes occurring in the endometrium every ~28 days. (menses = endometrium every ~28 days. (menses = months).months).
- Starts at puberty till menopause.- Starts at puberty till menopause.
It is under the control of ovarian hormones.It is under the control of ovarian hormones.
Stages
The menstrual phase (3-5 days):The menstrual phase (3-5 days):
- No fertilization -----> spasm in the uterine arterioles ---- > 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.
II. The Follicular (Proliferative) phase (9 days)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 of mucin, glycogen.
III. The secretory (progestational) III. The secretory (progestational) phase (13 days)phase (13 days)
- Starts 2-3 days after ovulation.- Under the effect of progesterone of the
corpus 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 where estrogen and progesterone levels fall (due to degeneration of the corpus luteum).