Human Reproductive System Produces, stores, nourishes and transports functional gametes (egg and sperm).

1o Reproductive Organs = Gonads Gonads make gametes (sex cells) and the Sex Hormones. Ducts, accessory organs and glands assist gametes Fertilization - union of sperm and egg = zygote. 2o Reproductive Organs = External Genitalia

Male Gonads Female Gonads Testes produce sperm and testosterone. Ovaries produces eggs, estrogen and progesterone.

The Sex Chromosomes XX or XY Female Male 22 pairs of autosomal chromosomes + 1 pair of sex chromosomes. The Sex Chromosomes XX or XY Female Male X chromosome has about 1,100 genes on it. Y chromosome has about 80 genes on it.

Platypus: Researchers discovered it has 10 sex chromosomes, some of them linked to mammals and some to birds.

Endocrine Regulation of Reproduction Gonadotropin-releasing hormone (GnRH) From Hypothalamus, stimulates FSH and LH release. FSH: ↑ follicular development, ↑ estrogen (females). Required for sperm production (males). LH (ICSH in men): Ovulation. Regulates estrogen and progesterone (females). ↑ Testosterone (males)

Phenotypic Sex Apparent anatomical sex of individual Sexual differentiation Male Female Lack of Androgens Induced by Androgens Mostly Testosterone

Testosterone + Mullerian Inhibiting Factor Male

2o Sexual Characteristic Differences in anatomy and physiology between males and females = sexual dimorphism. Characteristic Males Females Pattern of hair growth Voice (pitch) Muscle mass Bone growth/density Sex drive Distribution of body fat Aggression

Genetic and Phenotypic Sex If person with XY has testes that fail to differentiate and secret hormones - Result? = genetic male, anatomical female If person with XY has normal testosterone levels but target tissue lacks receptors - Result? = genetic male, anatomical female (testicular feminization syndrome)

Sex Chromosome Abnormalities Female Genotype Syndrome Male XX Normal XY XO Turner  XXY Klinefelter XXX Triple-X XYY

Klinefelters’s Syndrome Person has 47 chromosomes, the extra one is a Y, genotype = XXY = Male Reduced fertility, small testicles, enlarged breast Turner’s Syndrome Person has 45 chromosomes, the X or Y is missing, genotype = XO = Female Usually Infertile, short, immature sex organs at adolescence

Triple-X Syndrome XYY Syndrome Women with 3X chromosomes - genotype is XXX “Super-females" or “Meta-females”. Taller, long legs, slender torsos, limited fertility.  XYY Syndrome Males with extra Y chromosome - genotype is XYY.  “Super-males“ often tall, high testosterone levels.  Usually fertile.  Both often unaware of chromosomal abnormality

Male Reproductive Structures

Male Reproductive Structures 1o Reproductive organ: Testes Held ‘outside’ body in the scrotum. Dartos muscle wrinkles skin of scrotum. Cremaster muscle pulls testes closer to body. Cremaster Reflex.

Ductus deferens – starts after tail of epididymis ~ 18 feet long ~ 3 weeks to travel through - Head - Body - Tail Stores sperm, recycles damaged ones, site of maturation of sperm Ductus deferens – starts after tail of epididymis

The Accessory Glands

Accessory Organs of the Male 1. Seminal vesicles 2. Prostate gland All secrete semen 2. Bulbourethral glands 1. Seminal Vesicles Paired glands - secretes 60% semen volume. Fibrinogen – converts to fibrin for clotting. Fructose – a monosacharide for energy. Prostaglandins – contract female tract.

2. Prostate Gland 3. Bulbourethral Glands Single gland - secretes 30% semen volume. Clotting proteins – to cause initial clots. Fibrolysin – to liquefy clots. 3. Bulbourethral Glands Paired glands (~5% semen volume). Alkaline mucus secretion (to neutralize). Lubricating properties.

Semen Typical ejaculation releases 2-5 ml. Sperm count typically 50 – 100 million per ml. Sperm count below 20 million per ml, considered “infertile”. Sperm must be 2-3o F cooler than rest of body, hence kept ‘outside’ in scrotum.

The Penis Erectile tissue (3 masses) Two corpora cavernosa One corpus spongiosum (surrounds urethra) Erection – dilation of arterial smooth muscles. Erectile Dysfunction (ED)?

The Female Reproductive System Ovaries Uterine tubes Uterus Vaginal canal and vagina External genitalia

Female Reproductive System

Uterine Wall (Layers) Endometrium - innermost layer Functional layer, top 1/3 (sheds). Basal Layer, bottom 2/3 (remains). Myometrium – muscular (thickest ~90%). Perimetrium – outermost covering.

The Vagina – passage, connecting uterus to external genitalia. The External Genitalia: Labia majora – outer (larger) Labia minora – inner (smaller) Clitoris – erectile tissue (spongiosum) (prepuce = hood, foreskin of clitoris) Lesser and greater vestibular glands. Mons pubis