Endocrinology 13 - Reproductive Endocrinology Male Reproductive Physiology - Testes o Sperm development Testosterone is produced and site of action for testosterone - Epididymis & Ductus deferens o Sperm maturation · Storage o Exit - Seminal vesicle o Site of production of Seminal fluid o High conc. of fructose/prostaglandins o Clotting factors - Prostate o Provides material for the seminal fluid o Alkalinises vagina . Make the vaginal environment more alkaline . Triggers clotting factors o Triggers clotting factors o When the sperm enters the vagina, we want them to stay where they are, so the seminal fluid needs to be viscous so its stays there Sertoli Cells - Blood-testes barrier - Continuous sheet of cells with tight junctions - They form a protective barrier around the developing sperm - They are phagocytic o Eat up organisms that are seen as a threat - Secrete fluid to flush sperm into the epididymis - Secrete ABP (sex steroid binding protein) o Binds to testosterone to keep the local conc. high but in inactive form - Site of action for testosterone - Arranged into seminiferous tubules o Form an outer ring around the seminiferous tubules o Between the tubules are another type of cell and there are blood vessels Leydig cells - Interstitial cells (sit in between) - Endocrine cells - een the seminiferous tubules ised and secreted Lumen of seminiferous tubule - Spermatids Spermatozoa Secondary spermatocyte Sertoli cells Primary spermatocyte Spermatogonium Basement membrane Fibroblast- Tight junction between Sertoli cells Leydig cells Capillary
Spermatogenesis - Continuous process - Single sperm takes 64 days to mature - 200 million sperm present at any one time Female Reproductive Physiology - Ovary o Female gonad o Egg development - Oviduct o Site of fertilisation o If not fertilised will travel down the oviduct and outside - Uterus o Implantation o Endometrium The female reproductive system occurs in a cycle with three distinct phases: - Follicular Phase o Primary follicles grow and mature into secondary follicle o One follicle per cycle will mature into oocyte o Then mature into mature follicle - Ovulation o Mature follicle is released from the gonad - Luteul phase o Remains of the ruptured follicle will form another endocrine cell . Corpus luteum o If fertilisation doesn't occur, this structure will degenerate o If fertilisation occurs, the corpus luteum will go on to form a major source of progesterone Hypothalamic-Pituitary-Gonadotrophin (HPG) Axis Same for both males and females - Stimulus o E.g. puberty - Hypothalamus o Arcuate nucleus o Sends a gonadotropin rele anterior pituitary - Anterior Pituitary o Gonadotrophs cells o Sends luteinising hormone hormone (FSH) to the targ Hypothalamus Gonadotropin Releasing Hormone (GnRH) Anterior Pituitary Luteinising Hormone (LH) Follicle Stimulating Hormone (FSH) arcuate nucleus gonadotrophs Testes/Ovary Testosterone Inhibin Oestrogen Progesterone
- Testes/Ovary O Testosterone o Inhibin o Oestrogen/progesterone Feedback Loop - Testosterone will negatively feedback to the hypothalamus In males; o To stop the release of GnRH - And the anterior pituitary o To stop the release of LH/FSH