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
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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
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
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)