1 / 88

Chapter 28

Chapter 28. The Reproductive System. The Reproductive Systems. Reproductive organs grouped by function Gonads - testes and ovaries produce gametes and secrete hormones production of gametes, fluid, discharge into ducts indicate exocrine glands

baba
Download Presentation

Chapter 28

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 28 The Reproductive System

  2. The Reproductive Systems • Reproductive organs grouped by function • Gonads - testes and ovaries • produce gametes and secrete hormones • production of gametes, fluid, discharge into ducts indicate exocrine glands • production of hormones indicate endocrine glands • Ducts - transport, store, receive gametes • Accessory sex glands - gamete support • Supporting structures - various reproductive roles

  3. Male Reproductive System • Testes, system of ducts, accessory sex glands, several supporting structures (including penis)

  4. Male Reproductive System • Scrotum • 2 sacs that support testes • muscle and connective tissue • dartos muscle and fascia • cremaster muscle • location and temperature due to muscle contraction • sperm production requires temp 3 C below body temp • muscle contraction raises and lowers testes

  5. Male Reproductive System • Testes - testicles • paired oval glands 5 cm x 2.5 cm • develop in abdomen • begin to descend during 7th month of development • cryptorchidism

  6. Male Reproductive System • Testes surrounded by connective tissue • covered by tunica vaginalis (serous membrane) from peritoneum • more internal is tunica albuginea • forms septa and lobules • 200-300/testicle

  7. Male Reproductive System • 3 seminiferous tubules - each lobule • Each tubule lined w/ spermatogenic cells in various developmental stages

  8. Male Reproductive System • Spermatogonia to spermatazoa • Sustentacular (Sertoli) cells • blood-testis border • mediate testosterone FSH effects • phagocytize excess spermatid cytoplasm • control movement and sperm release to tubule • secrete fluid for sperm transport • Interstitial endocrinocytes (interstitial cells of Leydig) • located between tubules • secrete testosterone

  9. Male Reproductive System • Spermatogenesis • occurs in seminiferous tubule • production of haploid spermatozoa • about 74 days in humans • Spermatogonia • diploid • w/ mitosis some stay as stem cells • some undergo developmental changes  primary spermatocytes

  10. Male Reproductive System • Reduction division • secondary spermatocytes formed (haploid) • equatorial division • spermatids formed (haploid) • sperm cells do not completely separate • maintain cytoplasmic bridges due to incomplete nature of Y chromosome • Spermiogenesis • maturation of spermatids into spermatozoa • 10-14 days for maturation in ductus epididymus

  11. Male Reproductive System • Spermatozoa • 300 million/day mature • survive about 48 hrs following ejaculation • structure • head • nuclear material • acrosome - enzymes for penetration into egg • midpiece - site of metabolism for tail • tail - flagella

  12. Male Reproductive System • Hormones of brain-testicular axis • anterior pituitary drives changes during puberty • begins to secrete FSH, LH • controlled by GnRH from hypothalamus • LH - Interstitial endocrinocytes • testosterone • DHT • FSH - Sustentacular cells • ABP • Inhibin

  13. Male Reproductive System • Development • testosterone stimulates pattern development before birth (internal ducts) • DHT external genitals • estrogens from testes - brain development • Puberty - testosterone, DHT stimulate enlargement of male sex organs and secondary sexual characteristics

  14. Male Reproductive System • Testosterone - the gift that keeps on giving! • 2 sex characteristics • muscular, skeletal growth • heavier, thicker muscle, bones in men than women • also epiphyseal closure • pubic, axillary, facial and chest hair • oil gland secretion • larynx enlargement • sexual functions • male sexual behavior and aggression • spermatogenesis • sex drive in both male and female • metabolism - stimulates protein synthesis

  15. Male Reproductive System • Ducts • sperm and semen to lumen of seminiferous tubules  straight tubules  rete testis  epididymis • new sperm, fluid produce pressure to move things along • fluid - androgens, estrogens, K+, glutamic acid, aspartic acid

  16. Male Reproductive System • Epididymis • posterior border of testes • tightly coiled tube - head, body, tail • 6 m long if uncoiled • pseudostratified columnar epithelium • microvilli • reabsorb degenerated sperm • ductus epididymis • site of sperm maturation (10-14 days) -  motility • may remain in storage for a month, then reabsorbed

  17. Male Reproductive System • Ductus (vas) deferens • less convoluted,  diameter • ascends, enters pelvic cavity through inguinal canal • loops up, over urinary bladder ends in ampulla

  18. Male Reproductive System Posterior View

  19. Male Reproductive System • Spermatic cord - testicular artery, autonomic nerves, veins, lymphatic vessels, cremaster muscle ascend w/ vas deferens • Enter body through inguinal canal • Vasectomy - portion of each duct removed

  20. Male Reproductive System • Ductus (vas) deferens • pseudostratified columnar epithelium w/ heavy coat of muscle • stores, conveys sperm from epididymis to urethra during ejaculation • peristalsis

  21. Male Reproductive System • Ejaculatory Ducts • formed by ducts from seminal vesicle and ductus deferens • move sperm into prostatic urethra before ejaculation

  22. Male Reproductive System • Urethra • terminal tract of urinary, reproductive systems • 3 areas: • prostatic urethra • membranous urethra • spongy (cavernous) urethra • ends at external urethral orifice in bulb of penis

  23. Male Reproductive System • Accessory sex glands secrete liquid portion of semen • Seminal vesicles • base of urinary bladder •  60% of semen volume • secrete alkaline viscous fluid containing: • fructose, ascorbic acid • prostaglandins • vesiculase (coagulating enzyme)

  24. Male Reproductive System • Prostate • below bladder, around urethra • secretes milky, slightly acidic fluid with: • citrate • enzymes • Phosphatase • Fibrinolysin • Prostate specific antigen (PSA) • Bulbourethral (Cowper's) glands • beneath prostate gland at membranous urethra • secrete: • alkaline substance • Mucous • neutralize any acidic urine

  25. Male Reproductive System

  26. Male Reproductive System • Semen - mixture of sperm and secretions • avg vol 2.5-5 ml • 50-150 million sperm/ml • below 20 million/ml infertility • large numbers needed • slightly alkaline (7.2-7.6), milky and mucoid • decreases acidity of vagina • fructose for fuel • prostaglandins decrease mucous viscosity and reverse peristalsis • contains antibiotic • coagulates after ejaculation into vagina • different mechanism than blood clotting • breaks down in 5-20 minutes

  27. Male Reproductive System • Penis • root (attachment) • body (shaft) • glans penis

  28. Male Reproductive System • Root of penis - bulb (base of corpus spongiosum) • Glans penis w/ outer corona • terminal slitlike opening (external urethral orifice) • covering is prepuce (foreskin)

  29. Male Reproductive System • Body • 3 cylindrical masses of tissue surrounded by tunica albuginea • dorsolateral corpora cavernosa penis • midventral corpus spongiosum penis w/ spongy urethra • all surrounded by fascia and skin • each have blood sinuses

  30. Male Reproductive System • Erection • arteries dilate w/ sexual stimulation - PNS reflex • large quantities of blood enter sinuses • compress superficial veins from sinuses • trapped blood  erection • close bladder sphincter • prevent urine flow • prevent semen backflow • Ejaculation • sympathetic reflex • peristalsis • arterial vessels constrict, sinuses empty

  31. Female Reproductive System • Ovaries, uterine (Fallopian) tubes, uterus, vagina, vulva, mammary glands

  32. Female Reproductive System • Ovaries • paired organs in pelvic cavity • supported by several ligaments • almond size • homologous to testes

  33. Female Reproductive System • Ovary Histology • germinal epithelium around outside • tunica albuginea - connective tissue • stroma - connective tissue • cortex - outer dense layer w/ ovarian follicles • medulla - inner loose layer • ovarian follicles • vesicular ovarian (Graafian) follicle • corpus luteum

  34. Female Reproductive System • Oogenesis - formation of haploid ova in ovary • Steps • Reduction division - meiosis I • starts during fetal development, pauses • finishes after puberty • Equatorial division - meiosis II • pauses • finishes after fertilization

  35. Female Reproductive System • Uterine (Fallopian) tubes - oviducts • extend laterally from uterus to carry ova from ovaries to uterus • structure • infundibulum with fimbriae • ampulla • isthmus

  36. Female Reproductive System • Once a month ovarian follicle ruptures releasing secondary oocyte (ovulation) • oocyte swept into oviduct by fimbriae moves by peristalsis, cilia • fertilization can occur any time in next 24 hours • generally in ampulla • becomes a zygote • unfertilized oocytes disintegrate

  37. Female Reproductive System

  38. Female Reproductive System • Uterus • site of menstruation, implantation, fetal development, labor • between urinary bladder and rectum • size, shape of inverted pear

  39. Female Reproductive System • 3 parts of Uterus • fundus • body - isthmus

  40. Female Reproductive System • cervix • narrow portion that opens into vagina • produces cervical mucous; (20-60 ml/day) • more receptive to spermatazoa at or near ovulation • otherwise  mucous plug • cervix, mucus • protect spermatazoa • provide nutrients • role in capacitation • Cervical canal in cervix • internal os • external os

  41. Female Reproductive System • Uterus bends between body and cervix • Uterus enters vagina at right angle

  42. Female Reproductive System • Ligaments provide stability • broad ligaments • uterosacral ligaments • cardinal ligaments • round ligaments

  43. Female Reproductive System • 3 uterine layers • Perimetrium - visceral peritoneum • Myometrium • 3 layers of smooth muscle • thickest in fundus • thinnest in cervix • expulsion

  44. Female Reproductive System • Endometrium • highly vascular • surface layer • simple columnar epithelium • ciliated, secretory cells • uterine (endometrial) glands

  45. Female Reproductive System • Endometrium - divided into 2 layers: • stratum functionalis (functional layer) - shed during menstruation • stratum basalis (basal layer) - gives rise to stratum functionalis

  46. Female Reproductive System • Blood supply from uterine arteries • arcuate arteries - circular around myometrium • radial arteries penetrate into myometrium w/ 2 branches: • straight arterioles • terminate in basilis • supply materials to regenerate functionalis • spiral arterioles • penetrate functionalis • change during menstruation • Drained by uterine veins

  47. Female Reproductive System • Endoparasitic expulsion

  48. Female Reproductive System • Vagina • Tubular, fibromuscular organ with mucous membrane • Between bladder, rectum • superiorly attached to uterus • recess (fornix) around attachment to cervix • Several functions • passage for menstrual flow, childbirth • receives semen

  49. Female Reproductive System • Vagina histology • Mucosa continuous w/ uterus • non-keratinized stratified squamous epithelium and connective tissue in folds (rugae) • mucosal cells have large stores of glycogen • upon decomposition produce organic acids - lo pH • dendritic (APC) cells - AIDS? • Muscularis • smooth muscle - outer circular, inner longitudinal • stretches to receive penis and for childbirth • Adventitia - areolar connective tissue

  50. Female Reproductive System • Mons pubis • Anterior to vaginal, urethral openings • Adipose tissue covered by skin, hair • Labia majora • Lateral skin folds (adipose tissue) with sebaceous and sudoriferous glands • Homologous to scrotum • Labia minora • Smaller, medial folds with sebaceous glands • Homologous to spongy urethra • Vulva - pudendum • Female external genitalia this is a test

More Related