Anatomy lecture 26

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Anatomy lecture 26
2011-03-03 16:52:00

Male reproductive system
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  1. Components of the system
  2. lecture notes
  3. General overview:
    • spermatic cord
    • scrotum
    • testes (seminiferous tubules, Sertoli and Leydig cells,
    • spermatogenesis and spermiogenesis)
    • epididymis
    • ductus deferens (vas)
    • urethra
    • penis
    • seminal vesicles
    • prostate gland
    • bulbourethral glands
  4. lecture notes
  5. Descent of the Testes:
    • intra abdominal near the kidney
    • they are translocated inferiorly and anteriorly to the abdominal wall
    • gubernaculum testis
    • during the third trimester they move through the abdominal wall and take with them a pocket of the peritoneal cavity
    • as the testes move through the wall they are accompanied by the ductus deferens, blood vessels, nerves and lymphatics
  6. lecture notes
  7. Spermatic Cord:
    • fascia, connective tissue and muscle
    • wrap the blood vessels, nerves and lymphatics that supply the testes
    • starts at the deep inguinal ring, extends through the inguinal canal and comes through the superficial inguinal ring into the scrotum
  8. lecture notes
  9. Scrotum:
    • sac of skin and fascia outside of the abdominopelvic cavity
    • midline septum divides it into two compartments
    • keeps the testes from body temperature
    • dartos (means skinned) muscle: located in the skin of the scrotum
    • cremaster (the suspender) muscle: deep in scrotal wall
  10. lecture notes
  11. Testes:
    • 4-5 cm long, 2.5-3 cm in diameter
    • tunica vaginalis: extension of the peritoneum, covers lateral and anterior surfaces of the testes
    • tunica albuginea: fibrous coat or capsule, extension penetrate the testes dividing it into approximately 250-300 compartments called testicular lobules
    • testicular lobules: contains seminiferous tubules, loose connective tissue and lots of blood vessels
  12. lecture notes
  13. seminiferous tubules of the testes:
    • the actual sperm factories
    • approximately 80 cm long
    • total length in both testes is approximately 0.5 miles
  14. lecture notes
  15. Leydig cells:
    • located in the loose connective tissue between the seminiferous tubules
    • produces and secretes testosterone
  16. lecture notes
  17. blood supply:
    • testicular arteries (branches of the abdominal aorta)
    • testicular veins pampiniform plexus surround the testicular arteries
  18. innervation:
    • autonomic nervous system
    • sensory
  19. Spermatogenesis:
    • spermatogonia: stem cells that form during embryonic development
    • process stimulated by LH, FSH and testosterone
    • through cell division form spermatogonia and primary permatocytes (meiosis I) and spermatids (meiosis II)
  20. lecture notes
  21. Spermiogenesis:
    • maturation of spermatids resulting in spermatozoa
    • occurs with the help of the Sertoli cells
  22. lecture notes
  23. Sertoli cells:
    • create blood-testes barrier
    • support spermatogenesis and spermiogenesis
    • Secrete inhibin and androgen binding protein (ABP)
  24. lecture notes
  25. Structure of a Sperm:
    • approximately 65 um long
    • head, neck, middle piece, tail
    • head: flat and oval, contains the nucleus and acrosomal cap (bag of enzymes)
    • neck: connects the head to the middle piece, contains the cellular components that form the flagellum
    • middle piece: continuation of the neck, mitochondrial collar
    • tail: flagellum, source of movement for the sperm
  26. lecture notes