Reproductive System. Testes. Accessory reproductive organs. gametogenesis hormones. Reproductive tract & Glands

Transcription

1 Reproductive System Testes gametogenesis hormones Accessory reproductive organs Reproductive tract & Glands transport gametes provide nourishment for gametes

2 Hormonal regulation in men Hypothalamus - puberty GnRH: Pulsatile secretion (peaking every 1.5h) Pituitary FSH (=> sertoli cells) LH (=> Leydig cells) Testes Sertoli cells: androgen-binding protein ABP: maintains testosterone in seminiferous tubules Inhibin: sperm # => (-)-feedback to ant pituitary Interstitial (Leydig) cells: testosterone body wide effects Spermatogenesis in seminiferous tubule

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4 Spermatogenesis begins during puberty & continues throughout life Location: seminiferous tubules ~ 400 million sperm produced each day Semen normal volume: 2-6.5mL million sperm per ml Greater than 60% should be swimming for good fertility

5 Testosterone Primary sex characteristics Masculinizes embryonic genitalia Secondary Sex Characteristics axillary and facial hair Enlarges larynx: deep voice Skin: thickens and oily anabolic effects: Bones and skeletal muscles Pubescent development of reproductive structures Basis of sex drive (libido) Masculinizes embryonic brain Boosts basal metabolic rate spermatogenesis

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7 Reproductive System Gonads: gametogenesis hormones Accessory reproductive organs: Reproductive tract & Glands transport gametes provide nourishment for gametes

8 Regions: cortex & medulla ovarian follicle Oocyte surrounded by Follicle cells (1 cell layer) Granulosa cells (>1 cell layer) stages of follicular development primordial follicle Primary follicle secondary follicle graafian follicle Corpus luteum Ovaries

9 Menstrual Cycle refers to the changes in the follicles of ovary & in the endometrium of uterus Ovarian cycle Monthly series of events associated with maturation of egg Uterine cycle Copyright 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

10 Ovarian Cycle Two consecutive phases (in 28-day cycle) Follicular phase(1 14) period of follicle growth Duration: varies Luteal phase (15 28) period of corpus luteum activity & uterus is prepared for pregnancy Duration: constant 2013 Pearson Education, Inc.

11 Hypothalamus GnRH Pituitary gland Gonadotropin: FSH & LH Ovaries: follicles mature Thecal cells: androgens Granulosa cells Aromatase Inhibin: (-)-feedback to Pituitary => FSH estrogen (+)-feedback: estrogen (-)-feedback: FSH & LH Follicular Phase

12 Corpus luteum viable for <<<2wks Progesterone >> estrogens, Inhibin (-)-feedback => GnRH & FSH/LH No fertilization Degeneration of Corpus luteum progesterone, estrogen => GnRH & FSH/LH Fertilization corpus luteum remains viable for up to 3months hcg Luteal phase

13 Uterine Cycle refers to the cyclical changes that occur in the uterus in response to ovarian hormones 3 phases Menstrual phase (1-5) Proliferative phase (6-14) endometrial growth Secretory phase (15-28) conversion of endomentriun into secretory structures

14 Menstrual phase: 1 5 corpus luteum degenerates estrogens progesterone events Blood flow to tissue shedding of stratum functionalis menstrual flow menstrual bleeding and tissue pass out through the vagina

15 Proliferative Phase: 6-14 Estrogens Growth of Stratum functionalis Prepares for fertilized ovum implantation cervical mucosa thinning ( viscosity) facilitate sperm entry

16 Secretory Phase: Progesterone Vascularity in stratum functionalis Blood supply Glands undergo hypertrophy glycogen-rich fluids for nourishment Cervical mucus thickening ( viscosity) cervical plug prevent the embryo from being attacked by pathogens entering from the vagina

17 extrauterine effects of estrogen Estrogen Promotes bone lengthening & epiphyseal plate closure in adolescents skin hydration Inhibits bone resorption Stimulates and progesterone female pattern of fat deposit growth of axillary & pubic hair renal retention of Na+ HDL cholesterol LDL cholesterol Progesterone body Temperature promotes urination

18 Long-Term Regulation of Female Reproductive Function Menopause Estrogen levels decrease Reversal of some secondary sex characteristics Hot-flashes Increased risk of heart disease and osteoporosis Hormone Replacement Therapy (HRT) Copyright 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

19 Fertilization Fertilization usually takes place in the ampulla of the uterine tube Sperm must be introduced into female reproductive tract within five days before ovulation Sperm viable for 3-5 days, on average egg viable for hours Copyright 2008 Pearson Education, Inc., publishing as Benjamin Cummings.

20 Prevention of Ovulation During Pregnancy Progesterone inhibits GnRH, LH, and FSH release, preventing LH surge

21 Birth control Condoms and other barrier methods Male condom Spermicide Female condom Sponge Diaphragm

22 Birth control hormonal contraceptives RU-486 (Mifeprex) Blocks action of progesterone and sensitizes uterus to Misoprostol Misoprostol: prostaglandins Depo-Provera inhibit follicular development prevent ovulation

23 Ortho Evra Transdermal patch

24 Morning-after pill : progestin effective as a contraceptive after sexual intercourse prevents the sperm from reaching the egg prevents implantation of a fertilized egg Estrogen effective as a contraceptive suppresses ovulation

25 Others