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Human Reproductive System

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Presentation on theme: "Human Reproductive System"— Presentation transcript:

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

2 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

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

4 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.


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

7 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)

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

9 Testosterone + Mullerian Inhibiting Factor Male

10 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

11 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)

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

13 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

14 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

15 Male Reproductive Structures

16 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.

17 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

18 The Accessory Glands

19 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.

20 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.

21 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.


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

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

25 Female Reproductive System


27 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.


29 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

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