1. Lecture 12: Spermatogenesis
Animal Science 434
Lecture 12: Spermatogenesis

2. Spermiation

3. Temporal Relationships of Spermatogenesis

4. Spermatogenesis
57 days
Stallion

5. Multiple Generations of Germ Cells

6. Bull Spermatogenesis

8. Stages
Specific cellular associations within a small segment of a seminiferous tubule
stages are not the same length in time

9. Bull Spermatogenesis - Stages

10. Stages
Specific cellular associations within a small segment of a seminiferous tubule
stages are not the same length in time

11. Bull Spermatogenesis - Stages

12. Cycle
progression through sequence of all stages

13. Bull Spermatogenesis - Cycles

14. Cycle progression through sequence of all stages
4.7 cycles to form spermatozoa
some species variation

15. Duration of Spermatogenesis
Bull Ram Boar Stallion Man
cycle (days)
Spermatogenesis

16. Coordination of Stages Form Waves
some portion of seminiferous tubule is always releasing sperm

17. Compartmentalization of Spermatogenesis and the Blood Testis Barrier

18. Seminiferous Tubule and Interstitial Tissue

19. Interstitial Tissue Vascular System Provides Nutrients Oxygen
Blood Vessel
Vascular System Provides
Nutrients
Oxygen
Growth Factors
Hormones

20. Blood Vessel

21. Compartments
Tight Junctions
Myoid Cells
Luminal
Adluminal
Basal

22. Cycles and Stages

23. Compartmentalization
Basal
mitosis
spermatogonia (A, I, B)
primary spermatocytes
Adluminal
meiosis
secondary spermatocytes
spermatids
spermiogenesis
Lumen
spermiation

24. Blood Testis Barrier Sertoli cells and associated tight junctions
first appears at puberty
induced by FSH
after puberty can be maintained by FSH and/or testosterone
essential for meiosis
!!!!!

25. Capacity for Sperm Production
Species Testis Sperm/gm DSP Weight (gm) (X 106) (X 109)
Dairy Bull
Beef Bull
Ram
Boar
Stallion
Man

26. Duration of Spermatogenesis
Bull Ram Boar Stallion Man
cycle (days)
Spermatogenesis

27. Spermatogonial Renewal in the PrimateAp
Spermatogonial
Renewal in the
Primate Ad
Stem Cell
Pool
FSH B P

28. Capacity for Sperm Production
Species Testis Sperm/gm DSP Weight (gm) (X 106) (X 109)
Dairy Bull
Beef Bull
Ram
Boar
Stallion
Man

29. Variation in Sperm Production
Testis Size
Efficiency of spermatogenesis
mitotic division
degeneration of germ cells
Length of spermatogenesis

30. Apoptosis of Germ Cells
Season
Disease
Trauma or heat
Hormone levels
Normal part of spermatogenesis

31. Over Population of Spermatogonia
Tight Junction
Sertoli
Sertoli SG SG SG SG SG SG SG SG SG
Basement Membrane
Normal
Apoptosis Inhibited PS SG
Basement Membrane
Sertoli AP SG
Basement Membrane
Sertoli

32. Animation of Spermatogenesis