Reproductive Cycle Lecture Notes PDF

 Reproductive cycles Ovarian cycle Definition Cyclic changes in the ovary every lunar month Extension Begin at puberty till menopause wy Hormonal...

 Reproductive cycles Ovarian cycle Definition Cyclic changes in the ovary every lunar month Extension Begin at puberty till menopause wy Hormonal 1. Follicle stimulating hormone (FSH): control o Stimulates growth of ovarian follicles o Stimulate estrogen production by the follicles 2. Lutenizing hormone (LH): da a. Stimulates ovulation. b. Stimulates formation of corpus luteum Menstrual cycle en Definition Cyclic changes of endometrium every lunar month Extension Begin at puberty till menopause Hormonal 1. Estrogen: control o Stimulates proliferation of the endometrium. 2. Progesterone: H o Stimulates secretory changes in endometrium R. D Anatomist “Reproductive cycles”  Phases of ovarian cycle Follicular"pre-ovulation" phase “last for 14 days under control of FSH”  Primordial Follicles: wy 1ry oocyte is surrounded by layer of follicular cells.  Growing Follicle:  Zona pellucida surrounds the oocyte da  Follicular cells proliferate 3. Mature Graffian follicle:  Formation: en  The oocyte is surrounded by: 1. Zona pellucida 2. Corona radiate 3. Cumulus oophorus.  The capsule is formed of: H R. 1. Theca externa: outer fibrous layer 2. Theca interna: inner vascular layer D 3. Granulosa cells  Follicular cavity is filled with fluid containing estrogen.  Fate of follicle: undergo ovulation at 14th day to liberate the oocyte Anatomist “Reproductive cycles”  Ovulation  Definition: rupture of mature Graffian follicle  Onset: around 14th day  Causes: 1. Prostaglandins: stimulate contraction of theca externa. 2. Hormonal factor: LH. wy 3. Increased tension of the follicular cavity  Fate of Oocyte: fertilized by the sperm or degenerates within 24 hours if not fertilized da  Signs of ovulation: 1. increase of body temperature. 2. Heightened senses. 3. Breast tenderness. en 4. lower abdominal pain. 5. Increased sexual desire. Luteal "post-ovulation" phase H "last for 14 days under effect of LH"  Formation of corpus luteum R.  After ovulation, ruptured follicle becomes filled with blood forming corpus hemorrhagicum.  LH makes the follicular cells filled with yellow pigment forming the corpus luteum  Function of Corpus luteum: secretes progesterone D  Fate of the Corpus Luteum:  If fertilization occurs: corpus luteum increases in size & remains active till 4th month  If fertilization doesn’t occur: Corpus luteum decreases in size & form corpus albicans. Anatomist “Reproductive cycles”  Phases of menstrual cycle Menstrual phase Duration: 3 – 5 days Causes: Degeneration of corpus luteum →↓ progesterone →spasm of arteries →ischemia & degeneration of endometrium wy Features: 50 ml of unclotted blood containing: 1. Unfertilized ovum 2. Compact & spongy layers of endometrium Proliferative phase (corresponds to Follicular phase of ovarian cycle) da Duration: from 6th day to the 14th day Hormonal Control: estrogen secreted by the ovarian follicles. Features: Proliferation of endometrium & its thickness become 3 mm en Secretory phase (corresponds to Luteal phase of ovarian cycle) Duration: from 14th day to 28th day Hormonal Control: Progesterone from corpus luteum. Features: H  ↑thickness of endometrium (6 mm)  Glands filled with secretions & marked ↑in vascularity endometrium R. Fate of Secretory Phase: If fertilization occurs: corpus luteum grows → ↑progesterone → dilatation of arteries→↑thickness of endometrium → ↑secretions. D If fertilization doesn’t occur: Degeneration of corpus luteum → ↓ progesterone → spasm of arteries → degeneration of endometrium → menstruation. Anatomist “Reproductive cycles”