Male Infertility 2 Flashcards

Differentiate the clinical presentation of hypogonadotropic hypogonadism and hypergonadotropic hypogonadism in terms of reproductive health.

1
Q

What are the endocrine and exocrine functions of the testes?

A
  • Endocrine Testis Function
    • Testosterone 5 grams/day produced
    • “Free” Testosterone (Unbound): 2% of the total; biologically active fraction
    • “Bound” Testosterone: 98% of the total; albumin and SHBG
    • Testosterone metabolized to Dihydrotestosterone and Estradiol
  • Exocrine Testis Function
    • FSH effects on Sertoli Cells
    • Drives production of numerous secreted agents that drive spermatogenesis (androgen binding protein, transferrin, lactate, clusterin, ceruloplasmin).
    • These agents stimulate seminiferous tubule growth and development.
    • They also drive initiation of spermatogenesis during puberty
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2
Q

What is the role of Sertoli cells in spermatogenesis?

A
  • Sertoli Cells sit on the seminiferous tubule membrane and extend to the lumen of the seminiferous tubule
  • Sertoli cells linked by tight junctions - basis of the blood-testis barrier
    • The testis is thus an immunologically privileged site as a result
  • Sertoli cells nurse the developing sperm, which progress from the basement membrane to lumen
    • Forms microenvironment in which meiosis occurs
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3
Q

What is the role of germ cells in male spermatogenesis?

A
  • Germ cell stem cells are arranged on the basement membrane of the seminiferous tubule
  • These cells progress through development from basement membrane to lumen
    • Spermatogonia (Dark Type A [Ad], Pale type A [Ap], Type B)
    • Primary spermatocytes (preleptotene, leptotene, zygotene, pachytene)
    • Secondary spermatocytes
    • Spermatids (Sa, Sb, Sc, Sd1,and Sd2)
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