Spermatogenic function of testis.pptx

1. Spermatogenic
function of testis
Dr. Irtaza Rehman
(Author of the book The Extraordinary Life)

3. Learning objective
• To make them
• To understand
them

4. Q. Why testis
descend down in the
scrotum outside the
abdominal cavity??
• Ans. Because the formation
of sperm requires a
temperature lower than that
of body temperature.

5. Basic Functions of testis
Testis
Sperm
production
(seminiferous
tubules)
Testosterone
secretion
(Leydig cells)

6. Testis cross section

8. Spermatogenic
cells are present
within
seminiferous
tubules

12. Facts of Sertoli cells
• Line seminiferous tubules
• Non germ cells
• Secrete inhibin B  Inhibits FSH
• Secrete Androgen binding protein ABP: maintain local level of
testosterone
• Produce Macrophage inhibiting factor MIF: Sperms regulation
• Temperature sensitive: Inc Temp  Decreased sperm production and
decreased Inhibin B
• Converts testosterone into estrogen via aromatase
• Homolog of female granulosa cells

13. Facts of spermatogonia
• Line seminiferous tubules
• Germ cells
• Maintain germ cell pool
• Produce primary spermatocyte

14. Facts of Leydig cells
• Present in interstitium
• Endocrine cells
• Secrete testosterone in presence of LH
• Homolog of female theca interna cells

15. Q. What is the
effect of
temperature
on testosterone
production??
• Ans. No effect

16. Effect of temperature on sperms
Increase in Temperature will
Decrease sperm production
Increase sperm motility
Increase metabolism
Decrease life span

20. Blood Testis Barrier
 Physical barrier formed
between sertoli cells of the
seminiferous tubules.
 Isolates developed stages of
germ cells from the blood.
 More correct term is sertoli
cell barrier.
 Isolates gametes from
autoimmune attack

21. Q. One spermatoginum
produces 2 primary
spermatocytes, but only one
produces 4 sperms. Where
does the other one go?
• Ans. Other one autoreproduces
and converted into
spermatogonium and helps in
maintaining its number.

23. Spermiogenesis
(Spermatids  Sperms)

24. Spermiogenesis
(Spermatids  Sperms)
• 4 Phases
• Golgi phase: Golgi body enzymes form the
acrosomes
• Acrosomal phase: Acrosome condenses around the
nucleus
• Tail phase: Centriole elongates to form tail
• Maturation phase: Loss of excess cytoplasm

25. Mature Sperm
11 Microtubules
(Axoneme)
Hyaluronidase
Proteolytic enzyme
Average age  13 years Average speed  1-4 mm/min
Time required: 74 days Daily supply  120 Million

27. Ans. A

29. Motility of Sperm
Seminiferous tubules/Early epididymis
 Non motile
Epididymis after 18-24h
 ‘capability of motility’
(Inhibited by various factors)
Fully motile after ejaculation
Sperm do not become optimally motile until the pH of the
surrounding fluids rises to about 6.0 to 6.5

30. Hormones stimulating spermatogenesis
• Testosterone: + first stage; Growth & division
• LH: + Leydig cells  Testosterone
• FSH: + Sertoli cells , + Spermiogenesis
• Estrogens: By sertoli cells, + Spermiogenesis
• Growth hormone: Metabolic functions of testis,
+ Early division of spermatogonia

32. • Biochemical process of structural and functional
changes in sperm cell essential for reaching its full
fertilization capacity.
• Occurs in female genital tract

34. Q. Why out of
millions only one
sperm fertilizes
the ovum??

36. Jazakumullahu Khair ♥
(May ALLAH swt reward you with goodness)