Reproductive System

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Reproductive System

  1. 1. Reproductive System <ul><li>Goals: </li></ul><ul><li>Identify the structures of the male and female reproductive systems, including the gross and microscopic anatomy of the organs, structures and accessory glands and their basic functions. </li></ul><ul><li>Explain meiosis, spermatogenesis and oogenesis. </li></ul><ul><li>Discuss the changes that occur in the female reproductive system during pregnancy. </li></ul>www.freelivedoctor.com
  2. 2. General Organization <ul><li>Gonads  gametes & hormones </li></ul><ul><li>Ducts  transport of . . . ? </li></ul><ul><li>Glands  secrete fluid </li></ul><ul><li>Perineal structures = external genitalia </li></ul>www.freelivedoctor.com
  3. 3. Male Reproductive Anatomy <ul><li>Primary reproductive organs produce gametes </li></ul><ul><li>Secondary reproductive organs . . . </li></ul><ul><li>Male reproductive and urinary tracts are partially shared </li></ul>www.freelivedoctor.com
  4. 4. Testes (paired glands) <ul><li>Develop adjacent to kidneys </li></ul><ul><li>Descend into scrotum through inguinal canal (function of gubernaculum testis) </li></ul><ul><li>Peritoneal lining is carried along  lining of scrotum </li></ul><ul><li>Spermatic cord: bundle containing all the “duct work” </li></ul><ul><li>Cryptorchidism </li></ul>4 month www.freelivedoctor.com
  5. 5. Cryptorchidism <ul><li>In 3% of full-term and 30% of premature deliveries </li></ul><ul><li>Significance? - Treatment? </li></ul>www.freelivedoctor.com
  6. 6. Spermatic Cord Can be palpated as it passes over the pubic brim. Constituents : 1. Pampiniform plexus of spermatic vein 2. Spermatic artery 3. Ductus (vas) deferens 4. Lymphatics 5. Nerves-ilioinguinal and genitofemoral Fig 27.3 www.freelivedoctor.com
  7. 7. Scrotum <ul><li>Function: supports and protects testes </li></ul><ul><li>Structure: Skin & underlying superficial fascia </li></ul><ul><ul><li>Dartos muscle in dermis </li></ul></ul><ul><ul><li>Cremaster muscle - continuous with abdominal wall muscles (?) </li></ul></ul><ul><li>Involuntary contraction (cremasteric reflex) in response to ________ </li></ul><ul><li>Scrotal sac forms 2 separate chambers </li></ul>www.freelivedoctor.com Cremaster muscle
  8. 8. Structure of Testes <ul><li>Fibrous capsule – tunica albuginea – surrounds testes </li></ul><ul><li>Scrotal cavity – lined by tunica vaginalis – parietal and visceral layers </li></ul><ul><li>200-300 lobules </li></ul><ul><li>3 seminiferous tubules </li></ul>www.freelivedoctor.com
  9. 9. From Spermatocyte to Spermatozoon <ul><li>Spermatogenesis : Meiosis of primary spermatocytes  spermatids </li></ul><ul><li>Spermiogenesis : Spermatid maturation into spermatozoa within Sertoli cells </li></ul><ul><li>Spermiation: Spermatozoon released into lumen </li></ul>www.freelivedoctor.com
  10. 10. Sustentacular (Sertoli) Cells <ul><li>Maintenance of blood testis barrier </li></ul><ul><ul><li>special lumen fluid high in sex hormones, K + and aa </li></ul></ul><ul><ul><li>protection from immune attack ( due to sperm specific ag) </li></ul></ul><ul><li>Suspend spermatids and support spermatogenesis and spermiogenesis </li></ul><ul><ul><li> FSH and Testosterone work via Sertoli cells </li></ul></ul><ul><li>Secretion of inhibin to slow sperm production </li></ul><ul><li>Secretion of androgen-binding protein (ABP) </li></ul>www.freelivedoctor.com
  11. 11. Anatomy of a Spermatozoon <ul><li>Mature sperm has 3 portions: </li></ul><ul><li>Head with acrosome (containing _______ ) </li></ul><ul><li>Middle piece with nucleus and lots of ? </li></ul><ul><li>Tail - flagellum - (rotating in corkscrew fashion) </li></ul>See fig 27-6 www.freelivedoctor.com
  12. 12. Epididymis <ul><li>~ 7 m long </li></ul><ul><li>Head - superior, receives spermatozoa </li></ul><ul><li>Body - distal and inferior </li></ul><ul><li>Tail - leads to ductus deferens </li></ul><ul><li>Functions: </li></ul><ul><li>1) Monitors and adjusts tubular fluid (stereocilia!) </li></ul><ul><li>2) Recycles damaged spermatozoa </li></ul><ul><li>3) Stores sperm and facilitates maturation </li></ul>Rete testis and Efferent ductules www.freelivedoctor.com
  13. 13. Pathway of Sperm <ul><li>Seminiferous tubules </li></ul><ul><li>Rete testis </li></ul><ul><li>Epididymis </li></ul><ul><li>Vas (ductus) deferens </li></ul><ul><li>Ampulla of vas deferens </li></ul><ul><li>Ejaculatory duct </li></ul><ul><li>Prostatic urethra </li></ul><ul><li>Membranous urethra </li></ul><ul><li>Penile (spongy) urethra </li></ul>www.freelivedoctor.com
  14. 14. Accessory Glands <ul><li>Provide for 95% of the seminal fluid </li></ul><ul><li>1) Seminal Vesicles </li></ul><ul><li>Paired, on back wall of urinary bladder </li></ul><ul><li>Tubular (~ 15 cm) </li></ul><ul><li>Produce 60% of semen, hormones, fructose, etc. </li></ul><ul><li>Activate sperm (leading to motility) </li></ul>www.freelivedoctor.com
  15. 15. Prostate Gland <ul><li>20 - 30% of seminal fluid </li></ul><ul><li>Single, doughnut-shaped </li></ul><ul><li>Secretion contains: </li></ul><ul><ul><li>Citrate </li></ul></ul><ul><ul><li>Seminal plasmin (mild antibiotic) </li></ul></ul><ul><ul><li>Prostate specific antigen (PSA) – blood test for ? </li></ul></ul>www.freelivedoctor.com
  16. 16. Bulbourethral glands (Cowper’s glands) <ul><li>Pea size, paired, at base of penis </li></ul><ul><li>Produce about 10% of semen </li></ul><ul><li>Alkaline mucus - function?? </li></ul>www.freelivedoctor.com
  17. 17. Semen <ul><li>2-5 ml ejaculate </li></ul><ul><li>Ejaculation of semen by pelvic floor and penile muscles (Sympathetic division induces peristalsis in tract) </li></ul><ul><li>Constituents: </li></ul><ul><li>1. sperm - 20 - 100 million sperm/ ml </li></ul><ul><li>2. seminal fluid - see above glands </li></ul><ul><li>3. enzymes - proteases and seminalplasmin </li></ul>www.freelivedoctor.com
  18. 18. Penis <ul><li>Root - fixed to ischial ramus </li></ul><ul><li>Body with erectile tissues </li></ul><ul><li>Glans – enlargement of corpus spongiosum </li></ul><ul><ul><li>Prepuce - foreskin – partially covers glans and surrounds external urethral meatus (may be removed in circumcision ) </li></ul></ul><ul><ul><li>Preputial glands - produce smegma (supports bacterial growth, such as E. coli ) </li></ul></ul>www.freelivedoctor.com
  19. 19. Female Reproductive System <ul><li>All organs are internal and closely associated </li></ul><ul><ul><li>Primary reproductive organs: ? </li></ul></ul><ul><ul><li>Secondary reproductive organs : ? </li></ul></ul>Female repro system must produce gametes AND maintain developing embryo
  20. 20. Ovaries <ul><li>Suspended by ovarian ligament & suspensory ligament </li></ul><ul><li>Functions: </li></ul><ul><li>Ova production </li></ul><ul><li>Hormone production </li></ul>
  21. 21. Oogenesis ( = ovum production) <ul><li>takes place inside ovarian follicles in ovaries as part of ovarian cycle </li></ul><ul><li>Oogonia (= stem cells) complete mitotic divisions before birth </li></ul><ul><ul><li>At birth: ~ 2 mio primary oocytes </li></ul></ul><ul><ul><li>At puberty: ~ 400,000 primary oocytes </li></ul></ul><ul><ul><li>40 years later: 0 (even though only ~ 500 used)  Atresia </li></ul></ul>
  22. 22. Oogensis <ul><li>Ovarian cycles start at puberty under influence of ___ </li></ul><ul><li>Primordial follicle </li></ul><ul><li>Primary follicle </li></ul><ul><li>Secondary follicle </li></ul><ul><li>Tertiary (Graafian follicle) </li></ul>Each month some proceed Few proceed Few proceed
  23. 23. Primordial Follicle or Egg Nests (simple squamous layer) in cortex Present at birth
  24. 24. Primary Follicle Oocytes Follicle cells Follicles enlarge in response to FSH and produce estrogens
  25. 25. Secondary Follicle Few relative to number of primary follicles Produce follicular fluid Rapid enlargement = Clear glycoprotein layer
  26. 26. Tertiary or Graafian Follicle Spans entire width of cortex First meiotic division being completed: 1  oocyte divides into one 2  oocyte and one polar body
  27. 27. Oogenesis Ovulation Happens in tertiary follicle Suspended in prophase I Stops in Metaphase II
  28. 28. Ovulation <ul><li>Oocyte and follicular cells shed into abdominal cavity </li></ul><ul><li>then </li></ul><ul><li>Empty follicle forms corpus luteum which produces progesterone </li></ul><ul><li>Corpus luteum degenerates and becomes corpus albicans </li></ul><ul><li>GnRH increases under low estrogen and progesterone levels </li></ul>
  29. 29. Uterine Tube <ul><li>= Fallopian tube = oviduct = salpinx </li></ul><ul><li>Two muscular tubes </li></ul><ul><ul><li>infundibulum with fimbriae </li></ul></ul><ul><ul><li>Ampulla (place of fertilization) </li></ul></ul><ul><ul><li>Isthmus </li></ul></ul><ul><ul><li>intramural portion </li></ul></ul><ul><li>Tubal ligation </li></ul>Fig 27-14
  30. 30. Uterine Tube Histology <ul><li>Ciliated and non-ciliated simple columnar epithelium </li></ul><ul><li>Ciliary movement and periodic peristaltic contractions move ova </li></ul><ul><li>Secretion of nutrient substances </li></ul>
  31. 31. The Uterus <ul><li>Uterine wall ~ 1.5 cm </li></ul><ul><li>made up of </li></ul><ul><ul><li>Endometrium, </li></ul></ul><ul><ul><li>Myometrium, </li></ul></ul><ul><ul><li>Incomplete perimetrium </li></ul></ul><ul><li>Blood supply </li></ul><ul><ul><li>Uterine arteries from internal iliac </li></ul></ul><ul><ul><li>Ovarian arteries from abdominal aorta (inferior to renal arteries) </li></ul></ul>Fig 27-16
  32. 32. Histology of Endometrium <ul><li>Functional zone – deciduum, sheds during menses </li></ul><ul><ul><li>menstruation - flow sheds functionalis layer of endometrium </li></ul></ul><ul><ul><li>proliferative phase - under influence of estrogen basal cells proliferate </li></ul></ul><ul><ul><li>secretory phase - progesterone maintains functionalis </li></ul></ul><ul><li>Basilar zone – permanent layer, deep to functionalis </li></ul>
  33. 33. Functions of Uterus <ul><li>Protection of embryo/fetus </li></ul><ul><li>Nutritional support </li></ul><ul><li>Waste removal </li></ul><ul><li>Ejection of fetus at birth </li></ul>
  34. 34. Cervix and Vagina <ul><li>Cervix attaches to vagina at ~ 90° angle </li></ul><ul><li>Fornix – pocket surrounding uterine cervix (surgical access to pelvic cavity; location of birth control device) </li></ul><ul><li>Vagina – fibro-muscular organ serving as </li></ul><ul><ul><li>receptacle for intercourse </li></ul></ul><ul><ul><li>passageway for menstrual products </li></ul></ul><ul><ul><li>birth canal </li></ul></ul>
  35. 35. The Mammary Gland <ul><li>Modified sweat gland </li></ul><ul><li>Overlaying the ____________ muscle </li></ul><ul><li>15-20 separate lobes separated by suspensory ligaments; each lobe contains several secretory lobules </li></ul><ul><li>Lactiferous ducts leaving lobules; converge into 15-20 lactiferous sinuses </li></ul><ul><li>Milk stored in lactiferous sinus until released at tip of nipple </li></ul>
  36. 36. Lymphatic Drainage of Mammary Glands . . . <ul><li>. . . is of considerable clinical importance, why ?? </li></ul>

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