Reproductive System Section 1 Reproductive and Hormonal Functions of the Male Section 2. Reproductive and Hormonal Functions of the Female Section 3. Hormonal control of the menstrual cycle Section 4 Pregnancy Section 5 Oxytocin

Section 1 Reproductive and Hormonal Functions of the Male

Functions of testes spermatogenesis –seminiferous tubules secrete hormones – testosterone - by the instestitial cels of Leydig, – inhibin - by Sertoil cells

I. Endocrine Function of Testes Androgens: testosterone, dihydrotesterone ( 双氢睾酮） and androstenodione （雄烯二酮） Function of testosterone –Maintenance of spermatogenesis –Stimulation of development of genitalia. –Development and maintenance of the male secondary sexual characteristics. –Maintenance of libido. –Effect on metabolism. increases anabolism of protein, causes growth of the bones deposition of calcium salts enhancement of production of red cells.

Plasma Testosterone at Different Age in Male

Endocrine Function of Testes (cont.) Inhibin –a glycoprotein with a molecular weight of 31,000-32,000 –Secreted by by Sertoil cells in testis –potent inhibitory effect on FSH secretion by pituitary gland. –slightly inhibitory in GnRH secretion.

II. Regulation of Testis Function Hypothalamic- Pituitary-Testis Axis –GnRH –FSH, LH –Testerone Negative Feedback Mechanism –Testosterone –Inhibin Local regulation in testes

Relationship between gonadotropin, testerone and age in males

Section 2 Reproductive and Hormonal Functions of the Female

I. Menstruation, Ovulation and Hormonal Regulation Menstruation cycle or female sexual cycle –Uterine cycle Proliferative phase (estrogen phase) Secretary phase (progesterone phase) Menstruation –Ovarian Cycle Follicular phase Ovulation Luteal phase

Uterine Cycle Proliferative phase (estrogen phase) Secretary phase (progesterone phase) Menstruation

Ovarian Cycle Follicular phase Ovulation Luteal phase

Endocrine Functions of Ovaries Physiological function of estrogen –On sexual organs –On secondary female sexual characteristics –On metabolism –others Physiological function of progesterone –on uterus –on breasts –thermogenic effect –others

Section 3. Hormonal control of the menstrual cycle

Section 4 Pregnancy

I. Fertilization and Implantation

II. Hormones of Placenta Human Chorionic Gonadotropin (HCG) Progesterone and Estrogen Human Chorionic Somatommotropin (HCS)

Human Chorionic Gonadotropin (HCG) glycoprotein with a molecular weight of 39,000 secreted by the syncytial trophoblast cells can be measured in the blood 8 to 9 days after ovulation Function: identical to LH in its effect maintain the corpus letum

Progesterone and Estrogen Secreted by corpus luteum before 5-6 weeks of pregancy and by placenta later maintain the endometrium and prevent menstruation Estrogen: cause enlargement of uterus, breasts and mother’s female external genitalia Progesterone: decrease the contractility of pregnant uterus

Human Chorionic Somatommotropin (HCS) protein with molecular weight of 38,000 begins to be secreted by the placenta at the 5th week of pregnancy Secretion in direct proportion to the weight of placenta. Function –stimulates growth of fetus –regulates metabolism of carbohydrate, fat and protein in both the fetus and the mother

Changes of Hormones during Pregancy

妊娠期间 血中激素