1. The Male Reproductive System

2. Components
Scrotum
Testes
Duct system
Penis
Accessory glands

3. Scrotum Skin Dartos muscle (smooth) wrinkles Septum
Cremaster muscle (skeletal) (lifts)

4. Scrotum Temperature Spermatic cord
Optimal for sperm development is 3°C below body temp (~91 F)
Controlled by muscles
Spermatic cord
Testicular artery
Plexus of veins
Nerves
vas deferens (aka ductus defrens)

5. Testes – gross anatomy ~4 cm long, 2.5 cm wide Tunica vaginalis
Tunica albuginea (capsule)
Septa
lobules
Seminiferous tubules
Epididymis

6. Descent of the Testes
3 mos.
7 mos.
birth

7. Seminiferous tubules Spermatogenic cells
Spermatogenesis begins at puberty
~400 million sperm/day

8. Spermatogenic cells Spermatogonia Primary spermatocytes
On basal lamina
Mitosis
Primary spermatocytes
1st meiotic division
Secondary spermatocytes
2nd meiotic division
Spermatid
Haploid
4 from each 1° spermatocyte
24.4b

9. Seminiferous tubules Spermatogenesis Spermatogonia 1° spermatocyte
Spermatid

10. Hormones Spermatogenesis controlled by
FSH (follicle stimulating hormone) from pituitary
Testosterone from Leydig (interstitial) cells of testes
secretions from Sertoli cells

11. Spermiogenesis Spermatid  spermatozoan Head Midpiece Tail Nucleus
Acrosome (lysosome)
Midpiece
Base of tail
Mitochondria
Tail
Long flagellum

12. Spermiogenesis
Spermatid  spermatozoan

13. Sustentacular (Sertoli) cells
Nurse cells
Extend from basal lamina to lumen
Connected to each other by tight junctions
Nourish spermatogenic cells
Transport spermatogenic cells
Phagocytize excess cytoplasm
Secretions regulate spermatogenesis

14. Sustentacular cells
2 Sertoli cells with associated spermatogenesis cells.

15. Interstitial (Leydig) cells
Secretes testosterone
sER for steroid production
Controlled by LH from pituitary

16. Ducts
Epididymis
Ductus deferens
Ejaculatory duct
(urethra)

17. Epididymis Located in scrotum
Between seminiferous tubules and vas deferens
~6 m long

18. Epididymis Pseudostratified columnar epithelium
With stereocilia (long microvilli)
Smooth muscle
Sperm mature and stored

19. Ductus (vas) deferens From scrotum to pelvis
Forms ejaculatory duct with seminal vesicle duct
Empties into prostatic urethra
Thick muscularis
Propels sperm during ejaculation

20. Ductus deferens Microscopic anatomy Pseudostratified epithelium
Lamina propria
Muscularis
Inner longitudinal
Middle circular
Outer longitudinal

21. Urethra Shared with urinary system Prostatic urethra
Membranous urethra
Spongy (penile) urethra

22. Accessory Glands Seminal vesicle 60% of semen
Fructose to nourish sperm

23. Prostate Gland Prostate gland Surrounds prostatic urethra 30% of semen
Supports sperm

24. Penis Thin skin Spongy urethra Erectile bodies Corpus spongiosum
2 corpora cavernosa
Capsule
Vascular spaces CC cs

25. Erection Sexual excitement (parasympathetic)
 blood flow to erectile bodies
Squeezes veins shut
 blood pressure in erectile bodies

26. Ejaculation Sympathetic activation
Peristaltic contraction of smooth muscles in ducts and glands - ejaculation
Constriction of arteries
 blood pressure in erectile bodies