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The Reproductive System

Chapter 19. The Reproductive System. Introduction. Reproduction: process by which genetic material is passed from one generation to the next. Introduction (cont ’ d.). Meiosis produces sex cells Sperm from male and egg from female join to form zygote Zygote develops into embryo

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The Reproductive System

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  1. Chapter 19 The Reproductive System

  2. Introduction • Reproduction: process by which genetic material is passed from one generation to the next

  3. Introduction (cont’d.) • Meiosis produces sex cells • Sperm from male and egg from female join to form zygote • Zygote develops into embryo • Embryo develops into fetus

  4. The Male Reproductive System

  5. Introduction • Testes: produce sperm and male sex hormones • Accessory glands: produce secretions • Accessory organs: scrotum • Penis: transporting and supporting structure

  6. Introduction (cont’d.)

  7. The Scrotum • Outpouching of abdominal wall • Supports the testes • Divided internally by a septum • Scrotal sac elevates and descends

  8. The Testes • Tunica albuginea: capsule covering with lobules • Convoluted seminiferous tubules • Spermatogenesis

  9. The Testes (cont’d.) • Spermatogenesis • Spermatogonia > primary spermatocytes > secondary spermatocytes > spermatids > spermatozoa • Sertoli cells: supply sperm cells with nutrients

  10. The Testes (cont’d.) • Interstitial cells of Leydig: produce testosterone

  11. The Testes (cont’d.)

  12. The Anatomy of the Spermatozoa • Three hundred million produced daily • Anatomy • Head: contains genetic material and acrosome • Acrosome has enzymes that aid sperm in penetrating covering of ovum • Middle piece: contains mitochondria • Tail: propels sperm

  13. The Anatomy of the Spermatozoa (cont’d.) • Anatomy of a sperm cell

  14. The Functions of Testosterone • Controls development, growth, and maintenance of male sex organs • Stimulates muscle buildup and bone development • Causes sperm maturation • Causes thyroid cartilage enlargement • Produces body hair patterns

  15. The Ducts of the System • Seminiferous tubules: transport sperm cells • Rete testis: network of ducts • Ductus epididymis: site of sperm cell maturation • Epididymis located on posterior border of testis

  16. The Ducts of the System (cont’d.) • Vas deferens: straightened portion of epididymis • Enclosed in spermatic duct • Ejaculatory duct: ejects spermatozoa into urethra

  17. The Ducts of the System (cont’d.) • Urethra: terminal duct • Prostatic urethra, cavernous urethra, urethral orifice

  18. The Accessory Glands • Seminal vesicles: produce viscous part of semen • Prostate gland: produces fluid part of semen • Bulbourethral glands: produce mucus

  19. Semen • Mixture of sperm cells and secretions • Provides energy to the sperm via fructose • Neutralizes acidity of vagina • Acts as a transport medium • Contains enzymes that activate sperm • Average volume is 2.5 to 6 mL • Seminalplasmin: destroys certain bacteria

  20. The Penis • Delivers spermatozoa to female reproductive tract • Glans penis: end of the shaft • Prepuce: loose skin covering glans penis • Circumcision: removal of prepuce

  21. The Penis (cont’d.) • Contains masses of spongy tissue with sinuses • Sinuses fill with blood resulting in erection • Compress veins so blood is retained • Help penis penetrate vagina • During ejaculation, sphincter at base of urinary bladder is closed

  22. The Female Reproductive System

  23. Introduction • Primary sex organs • Ovaries • Accessory organs • Uterine tubes, uterus, vagina, external genitalia • Accessory glands: produce mucus

  24. Introduction (cont’d.)

  25. The Ovaries • Held in position by ligaments • Covered by germinal epithelium • Tunica albuginea: cortex contains ovarian follicles • Ovarian follicles: eggs in various developmental stages • Primary follicle: contains oocyte

  26. The Ovaries (cont’d.)

  27. The Ovaries (cont’d.) • Oogenesis • Begins in developing female fetus (700,000 produced) • Puberty: ovarian cycle begins • Primary oocyte: first meiotic division • Mature egg: second meiotic division

  28. The Uterine or Fallopian Tubes • Transport ova to the uterus • Infundibulum: funnel-shaped end with fimbriae • Cilia sweep an ovum into uterine tube • Egg moved by peristalsis toward uterus • Fertilization occurs in upper third of tube

  29. The Uterus • Site of menstruation, egg implantation and labor • Pear shaped • Uterine cavity: interior of the body • Cervical canal: interior of the cervix • Uterine wall: endometrium, myometrium, perimetrium

  30. The Menstrual Cycle • Menstrual phase • Endometrial lining shed along with blood and mucus • Ovarian follicles begin development • Preovulatory or proliferative phase • Secondary follicle matures into graafian follicle • Ovulation is rupturing of graafian follicle

  31. The Menstrual Cycle (cont’d.) • Postovulatory or secretory phase • Corpus luteum develops • Secretes estrogen and progesterone • If fertilization and implantation do not occur • Corpus luteum degenerates and new cycle starts • If fertilization and implantation occur • Corpus luteum maintained for four months

  32. Animation – Ovulation Click Here to Play Ovulation Animation

  33. The Functions of Estrogen • Development of female secondary sex characteristics • Breast development, pubic hair, fat deposits, widening of the pelvic bone • Enlargement of: • Uterine tubes, uterus, vagina, external genitalia

  34. The Vagina • Passageway for menstrual flow • Receptacle for the penis • Lower portion of birth canal • Fornix: surrounds vaginal attachment to cervix

  35. The External Genitalia of the Female • Vulva: external genitalia • Labia: majora and minora • Clitoris: erectile tissue • Vestibule: vaginal and urethral orifices • Glands: Skene’s and Bartholin’s

  36. The External Genitalia of the Female (cont’d.)

  37. The Perineum

  38. The Perineum (cont’d.) • Diamond-shaped region at inferior end of trunk between buttocks and thighs • Divided into: • Anterior urogenital triangle containing external genitalia • Posterior anal triangle containing anus

  39. The Anatomy and Function of the Mammary Glands

  40. The Anatomy and Function of the Mammary Glands (cont’d.) • Produce milk in females • Contain 15 to 20 lobes with lobules • Lobules contain milk-secreting cells • Milk is conveyed through series of tubules • Areola: circular pigmented area around nipple

  41. The Anatomy and Function of the Mammary Glands (cont’d.)

  42. Pregnancy and Embryonic Development

  43. Pregnancy and Embryonic Development (cont’d.) • Egg fertilization 12-24 hours after ovulation • Zygote: fertilized egg • Moves down uterine tube into uterus • Blastula • Zygote embeds in endometrium, placenta develops

  44. Pregnancy and Embryonic Development (cont’d.) • Primary germ layers • Ectoderm: skin and nervous system • Mesoderm: muscles and bones • Endoderm: linings of organs and glands • Amnion: fluid-filled sac • Attached to embryo by umbilical cord • Parturition: childbirth

  45. Summary • Discussed the organs of the male reproductive system • Discussed the role of testosterone • Described the process of spermatogenesis • Discussed the organs of the female reproductive system

  46. Summary (cont’d.) • Discussed the role of estrogen • Described the process of oogenesis • Described the phases of the menstrual cycle • Discussed pregnancy and embryonic development

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