Chapter 16 ~ Human Reproduction

Mammalian reproduction, I The Human Male Testes~ male gonads Contained w/in scrotum due to temp. Seminiferous tubules~ sperm formation (spermatogenesis) Leydig cells~ hormone production Epididymis~ sperm development Vas deferens~ sperm propulsion Seminal vesicles~ semen Prostate gland~ anticoagulant; nutrients, sperm activation Bulbourethral glands~ acid neutralizer – cleanses urethra Penis/urethra~ semen delivery

Mammalian reproduction, II The Human Female Ovaries~ female gonads Follicle~ egg capsule Oocyte – immature egg Graafian follicle – contains mature eggs – ovulation (release) Corpus luteum~ hormone secretion Oviduct (fallopian tubes)~ fertilization Uterus/endometrium~ womb/lining – implantation site Cervix/vagina~ sperm receptacle

Spermatogenesis Puberty until death! Seminiferous tubules~ location Primordial germ cell (2N)~ differentiate into…. Spermatogonium (2N)~ sperm precursor Repeated mitosis into…. Primary spermatocyte (2N) 1st meiotic division Secondary spermatocyte (1N) 2nd meiotic division Spermatids (1N)~Sertoli cells provide nutrients Sperm cells (1N)

Oogenesis As embryo until menopause... Ovaries Primordial germ cells (2N) Oogonium (2N) Primary oocyte (2N) Between birth & puberty; prophase I of meiosis Puberty; FSH; completes meiosis I Secondary oocyte (1N); polar body Meiosis II; stimulated by fertilization Ovum (1N); 2nd polar body

The female pattern Ovarian/Menstrual cycles~ • Menstrual phase – endometrium sloughs off Proliferative (follicular) phase endometrium repairs and thickens Follicle-stimulating hormone (FSH) – causes primary follicle to grow Ovulation occurs – release of oocyte – triggered by luteinizing hormone (LH) Secretory (luteal) phase – glands release nutrients and lining becomes vascularized

Embryonic & fetal development Gestation~ pregnancy 1st trimester: organogenesis fetus (week 8; all adult features) HCG (human chorionic gonadotropin) hormone (menstruation override; pregnancy test detection) Parturition~birth Labor~uterine contractions Lactation~prolactin (triggered by parturition) & oxytocin (triggered by nursing) Mammary glands

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