Physiology of the female reproductive system

1. Different periods of Female  Neonatal period :  4 weeks  childhood: 4 weeks to age of 12  adolescence: menarche, age of  sexual maturity: begain 18, maintains for 30 years  peri-menopausal period:begain 40, maintains for years pre-menopause, menopause(last time of menorrhae), post-menopause  senility

2.The definition of menstruation  Menarche: the onset of the first menses occurs about two years after the onset of pubert occurs between 13 and 15 years of age anovulatory for first two years

 The first day of menstrual bleeding is considered day 1 of the menstrual cycle  The length of menstrual cycle is 28 –30 days  The duration of flow is 2-7 days  The volume of menstrual blood loss is 30ml-50mL(<80mL),darkness and nonclotting.

The Founction of ovary  Produce oocyte  Endocrine: produce female hormone

3.Reproductive cycle Devided into 3 phases  Menstruation: 1-4days  the follicular phase:5-14 days a number of follicles developing, only one dominant follicle others become atretic ovulation:14th, releasing oocyte  luteal phase: days unless pregnancy occurs

1) Development of ovary Ovarian cycle is divided into four phases  Development of follicles primitive follicles  primary follicles  secondary follicles  antrun/ developing follicles  maturity follicles  ovulation  corpus luteum  corpus albican

2)Ovarian steroid hormones  Estrogens  rise in plasma by 4th day of cycle  from granulosa cells and theca cells  negative feedback to FSH  positve feedback to LH

 Progesterone:  from corpus luteum  maximal production occurs 3-4 days after ovulation and maintained for 11 days  negative feedback on FSH and LH

4.Clinical manifestations of hormone changes 1)Endometrium be sloughed to a basal level in menstruation  proliferative phase: 5-14 days (stroma thickens,gland elongated) in follicular phase, a maximal thickness in ovulation  Secretory phase :15-28 days (stroma loose, edematous, vesseltwisted, gland tortous) in corpus luteum

 Menstrual phase:1-4 days Endomitrium is sloughed and bleeding onset

2)endocervix Cervical also changes in response to the reproductive cycle Cervical gland secrete thin,clear,watery,mucus in follicular phase maximal in ovulation Mucus becomes thick,opaque,tenacious in corpus luteum phase

3)vagina  Thickening and maturation of the surface epithelial cells responed to E2 in follicular phase  thickening and secretory changes of vaginal epithelium in corpus luteum phase

4)Hypothalamic thermoregulating center  Progesterone shifts the Basal body temperature upward(BBT)  BBT record is a useful tool to evaluate the reproductive cycle

5.H-P-O axis The control of menstruation is based on a feedback loop of H-P-O axis Hypothalamus  Producing GnRH(gonadotropin-releasing hormone)  be secreted in a pulsatile manner  be a pulse generator of cycle  be influenced by E and neurotransmitters

Pituitary  Producing Gonadotropins follicle-stimulating hormone(FSH) luteinizing hormone(LH)  be protein hormones secreted by the anterior pituitary gland  be pulsatile manner  be influenced by E,P, and other factors

Ovaries ovarian sex steroid hormones estradiol (E), progesterone(P)

Feedback of H-P-O axis Concept of feedback the magnitude and the rate of GnRH, FSH, LH are determined by E, P,  negative feedback : resulting in decreased secretion ofGnRH FSH,LH  positive feedback: resulting in increased secretion of LH,which triggers ovulation

Key words  reproductive cycle  menstruation  ovarian cycle  H-P-O axis  feedback