Reproductive system


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Reproductive system

  1. 1. Reproductive Systems Male & Female
  2. 2. Function To ensure survival of the species  To produce egg and sperm cells  To transport and sustain these cells  To nurture the developing offspring  To produce hormones  Other systems strive to maintain a state of homeostasis
  3. 3. Male & Female Include:  Reproductive organs called gonads that produce gametes (reproductive cells) and hormones  Ducts that transport gametes  Accessory glands and organs that secrete fluids
  4. 4. Male & Female Production of hormones that permit the secondary sex characteristics, such as breast development in women and beard growth in men
  5. 5. Male Functions  To produce, maintain and transport sperm (the male reproductive cells) and protective fluid (semen)  To produce and secrete male sex hormones responsible for maintaining the male reproductive system
  6. 6. Male Consists of:  A pair of testes  A network of excretory ducts  epididymis  vas deferens  ejaculatory ducts  Seminal vesicles  Prostate  Urethra  Penis
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  8. 8. External structure of the penis: • Glans penis • Prepuce (foreskin) • There is no verifiable health benefit to circumcision.
  9. 9. Circumcision shaft sutures coronaforeskin glans penis urethral opening
  10. 10. Male Testes / testicles (Gonads)  Produce sperm (Spermatogenesis)  Sperm production begins at puberty and continues throughout the life of a male
  11. 11. Male Testes / testicles (Gonads)  Produce testosterone  Hair patterns and voice changes  Development of the male accessory organs (prostate, seminal vesicles etc.)  Stimulates the effect of protein building in the body that is responsible for the greater muscle development and strength of the male
  12. 12. • Testes are the male gonads. • Seminiferous tubules- form sperm • Leydig cells (interstitial cells)- produce androgens (ex. Testosterone, ABP).
  13. 13. • Testes are located in the scrotum, outside the body cavity. • Keeps testicular temperature cooler than the body cavity. • Develop in the body cavity and descend into the scrotum just before birth.
  14. 14. Male Duct System  Epididymis  Sperm mature in epididymis  Vas Deferens  Transports mature sperm to the urethra  Ejaculatory ducts  empty into the urethra
  15. 15. Male Seminal vesicles  Attached to vas deferens  Produce a sugar- rich fluid (fructose) that provides energy to sperm
  16. 16. Male Prostate Gland  Makes fluid
  17. 17. Male Urethra  Tube that carries urine from the bladder to outside of the body  Also carries semen out of the body
  18. 18. Mature Spermatozoaacrosome head nucleus tail mitochondria
  19. 19. Vasectomy
  20. 20. Female Functions  Produces the female egg cells  Transports the eggs to the site of fertilization  The fertilization of an egg by a sperm, occurs in the fallopian tubes
  21. 21. Female Functions  After fertilization, provides a place for a baby to develop  If fertilization does not take place, the system is designed to menstruate  Produces female sex hormones that maintain the reproductive cycle.
  22. 22. Female:• Vagina uterus uterine tube• Cervix• Fallopian tube (uterian tube/oviducts)• Ovary• Uterus - Endometrium - Myometrium - Perimetrium ovary endometrium fimbriae myometrium perimetrium cervix vagina
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  24. 24. Female Vagina  Canal that joins the cervix (the lower part of uterus) to the outside of the body  Also is known as the birth canal
  25. 25. Female Uterus  Hollow, pear-shaped organ that is the home to a developing fetus  Divided into two parts:  the cervix, the lower part that opens into the vagina  Main body of the uterus, called the corpus.  The corpus can easily expand to hold a developing baby.  A channel through the cervix allows sperm to enter and menstrual blood to exit
  26. 26. Female Ovaries  Oval-shaped glands that are located on either side of the uterus  Produce eggs and hormones.
  27. 27. Female Fallopian Tubes  Narrow tubes that are attached to the upper part of the uterus and serve as tunnels for the egg cell to travel from the ovaries to the uterus  Fertilization of an egg by a sperm, normally occurs in the fallopian tubes  The fertilized egg then moves to the uterus, where it implants into the lining of the uterine wall
  28. 28. OogenesisOvary- contains 400,000 oocytes; release about 500 in a lifetime• Ovary- under influence of FSH. The follicles mature every 28 days• Primary follicle produces estrogens• And primary oocyte completes its 1st division produces 2ndary oocyte and polar body
  29. 29. Oogenesis• Aprox 1/2 way through the 28 day cycle the follicle reaches the mature Vesticular or Graffian follicle stage.
  30. 30. Oogenesis• Estrogen levels rise and release LH and FSH and triggers ovulation.
  31. 31. Oogenesis• The 2ndary oocyte travels down the uterine tube to the uterus.• If fertilized by sperm, it will produce a zygote Ovum in uterine tube
  32. 32. The Ovarian Cycle Follicular phase  1st approx 14 days but variable  Egg develops in a follicle  Stimulated by FSH (see next slide)  Estrogen produced Ovulation  Egg released from follicle (LH surge)  Egg in abdominal cavity  Picked up by fimbria of fallopian tube  Not necessarily halfway point Luteal phase  Postovulatory phase 14 days (more constant)  Corpus luteum develops from exploded follicle  Produces progesterone as well as estrogen  Progesterone stimulates uterus to be ready for baby  If no pregnancy, corpus luteum degenerates into corpus 33 albicans
  33. 33. Nearly mature follicle Oocyte develops the zona pellucida  Glycoprotein coat  Protective shell (egg shell)  Sperm must penetrate to fertilize the oocyte Thecal cells stimulated by LH to secrete androgens Granulosa cells (with FSH influence) convert androgens to estrogen (follicular cells called granulosa cells now) Clear liquid gathers to form fluid-filled antrum: now a secondary follicle Surrounding coat of granulosa cells: corona radiata Fully mature, ready to ovulate, called: ”Graafian follicle” 34
  34. 34. Ovulation Signalfor ovulation is LH surge Ovarian wall ruptures and egg released, surrounded by its corona radiata 35
  35. 35. Conception  After ejaculation into the vagina, sperm swim to meet an egg  Sperm live 5-7 days (need cervical mucus)  Eggs live about 12-24 hours, so conception only occurs during this short window  Fertilization occurs in the fallopian tubeEvents leading tofertilization:•Sperm binds to receptors onzona pellucida•Acrosomal reaction –enzymes digest a slit•Sperm passes through zona•Fusion of a single sperm’splasma membrane withoocyte’s plasma membrane•Cortical reaction: spermreceptors destroyed in zonaso no more enter; spermnucleus engulfed by egg’scytoplasmFertilization occursat the moment thechromosomes fromthe male and female 36gametes unite
  36. 36. Initial days Cleavage (cell division) Blastocyst stage by day 4: now in uterus 37
  37. 37. ImplantationBlastocyst floats for 6-9 days post2 days: “hatches”by digesting zona conception -enough to squeeze burrows intoout endometrium 38
  38. 38. Formation of Placenta Both contribute: •Trophoblast from embryo •Endometrial tissue from mother Not called placenta until 4th monthEmbryonicbloodcirculateswithin chorionicvilli, close tobut not mixingwith mother’sblood •Nutrients to baby •Wastes to 39 mom
  39. 39. The “Placental Barrier” Sugars, fats and oxygen diffuse from mother’s blood to fetus Urea and CO2 diffuse from fetus to mother Maternal antibodies actively transported across placenta  Some resistance to disease (passive immunity) Most bacteria are blocked Many viruses can pass including rubella, chickenpox, mono, sometimes HIV Many drugs and toxins pass including alcohol, heroin, mercury Placental secretion of hormones  Progesterone and HCG (human chorionic gonadotropin, the hormone tested for pregnancy): maintain the uterus  Estrogens and CRH (corticotropin releasing hormone): promote labor 40
  40. 40. Childbirt  Gestational period: averages 266 daysh  (this is time post conception; 280 days post LMP) Parturition: the act of giving birth: 3 stages of labor 1. Dilation: 6-12h (or more in first child); begins with regular uterine contractions and ends with full dilation of cervix (10cm) 2. Expulsion: full dilation to delivery – minutes up to 2 hours 3. Placental delivery: 15 minutes Dilation of cervis; head enters true pelvis Expulsion: head first safest as is largest part Delivery of the placenta 41 Late dilation with head rotation to AP position
  41. 41. Stages of Life Embryologically, males and females start out “sexually indifferent”  Gonads, ducts and externally identical structures  At 5 weeks gestation changes start to take place Puberty: reproductive organs grow to adult size and reproduction becomes possible  Between 10 and 15  Influence of rising levels of gonadal hormones  Testosterone in males  Estrogen in females Female menopause (between 46 and 54):  Loss of ovulation and fertility 42
  42. 42. Ectopic Pregnancy
  43. 43. Mammary glands (breasts) Modified sweat glands Both sexes but function (normally) only in lactating female Produce milk to nourish baby Respond to hormonal stimulation Not a part of the reproductive system Nipple surrounded by pigmented ring of skin, the areola Contain epithelial tissue that secrete milk. Milk drains into a series of ducts opening at the nipple. 44