The Male Reproductive System

1. The Male Reproductive System Michael Hall PhD University of California Los Angeles

2. Components of the Male Reproductive System

3. Embryology of Gonad Development Mesenchyme Genital ridge 6 weeks (male = female) Medulla Cortex 7-8 weeks Female Male

4. Functions of Testes Spermatogenesis-production of sperm a. spermatocytogenesis-mitotic division of spermatogonia b. meiosis-production of haploid spermatids c. spermiogenesis-maturation of spermatids to spermatozoa 2. Steroidogenesis-production of steroid hormones

5. Testis Head of epididymis Vas deferens Efferent ducts Seminiferous tubule Body of epididymis Septum Mediastinum testis Tunica albuginea Rete testis Tunica vaginalis Tubulirecti Tail of epididymis

6. T. albuginea Seminiferous tubules

7. Components of the seminiferous epithelium Lumen (DNA) Spermatozoa (N) Spermatid (N) Secondary spermatocyte (2N) Sertoli cell cytoplasm Primary spermatocytes Sertoli cell nucleus (4N) Spermatogonium (2N) Basal lamina CT

8. Spermatogenesis-production of sperm a. spermatocytogenesis-mitotic division of spermatogonia (2N) to primary spermatocytes (4N) b. meiosis-two successive divisions producing haploid spermatids (N) c. spermiogenesis-maturation of spermatids to spermatozoa (non-motile)

9. Cross section of a seminiferous tubule Leydig

10. Spermiogenesis

11. Sertoli Cells Lumen (DNA) Spermatozoa (N) Spermatid (N) Secondary spermatocyte (2N) Sertoli cell cytoplasm Primary spermatocytes Sertoli cell nucleus (4N) Spermatogonium (2N) Basal lamina CT

12. Sertoli cells form tight junctions Junctional complex JC

13. Functions of Sertoli Cells Support, protection, and nutritional regulation of the developing spermatozoa 2. Phagocytosis of residual bodies 3. Secretion of testicular fluid into lumen 4. Production of Androgen Binding Protein (ABP) 5. Secretion of Inhibin (suppresses FSH secretion)

14. Components of the seminiferous epithelium Lumen Spermatozoa (N) Spermatid (N) Secondary spermatocyte Sertoli cell cytoplasm (2N) Primary spermatocyte Sertoli cell nucleus (4N) Spermatogonium (2N) Basal lamina

15. Sertoli cells in seminiferous tubule Sertoli cells Sertoli cell

16. Leydig cells Leydig cells Leydig cells lie in the CT between the seminiferous tubules Early spermatids

18. Leydig cells Seminiferous tubule Seminiferous tubule Leydig cells Seminiferous tubule Seminiferous tubule

19. Function of Leydig cells and Testosterone The prime function of the Leydig cells is the production of testosterone. Testosterone has many separate but interrelated functions: a). differentiation and maturation of sperm in the seminiferous tubule (200x testosterone) b). Development and secretory activity of accessory sex glands ( seminal vesicle, prostate and bulbourethral glands c). development of male secondary sex characteristics (facial and pubic hair, muscularity, libido, obnoxious behavior, voice etc.)

20. Hormonal control of spermatogenesis Hypothalamus GnRH 1.LH stimulates synthesis of male sex hormones by Leydig cells LH 1 2.FSH stimulates Sertoli cells to synthesize ABP FSH 2 Inhibin from Sertoli cells 3.Leydig cells produce testosterone into blood into tubule 3 Seminiferous tubule

21. Components of the Genital Duct System seminal vesicle prostate gland urethra b-u gland efferent ducts epididymis vas deferens rete testis

22. Rete testis

23. Components of the Genital Duct System seminal vesicle prostate gland ampulla urethra b-u gland efferent ducts epididymis vas deferens rete testis

24. Efferent duct Epididymis smoothmuscle sc cilia smoothmuscle

25. Components of the Genital Duct System seminal vesicle prostate gland ampulla urethra b-u gland efferent ducts epididymis vas deferens rete testis

26. Efferent duct Epididymis smoothmuscle sc cilia smoothmuscle

27. Components of the Genital Duct System seminal vesicle prostate gland ampulla urethra b-u gland efferent ducts epididymis vas deferens rete testis

28. Vas deferens IL Smooth muscle layers C OL

29. Vas deferens stereocilia smooth muscle

30. Components of the Genital Duct System seminal vesicle prostate gland ampulla urethra b-u gland efferent ducts spermatic cord epididymis vas deferens rete testis

31. Spermatic cord vas deferens pampiniform plexus cremaster muscle

32. Pampiniform plexus of spermatic cord Nerve Arteries and veins

33. Vasectomy

34. The Accessory Sex Glands prostate gland seminal vesicle urethra b-u gland

35. Seminal vesicle Cross section of a single, highly coiled seminal vesicle surrounded by smooth muscle SM 1 2. High magnification of the mucosa of a seminal vesicle Epithelium 2

36. Prostate Gland Bladder Urethra Smooth muscle Capsule Mucosal glands Submucosal glands Main glands

37. Prostate Gland Glands and ducts SM Prostatic concretions

38. Prostate Gland Glands and ducts PC Smooth muscle and elastic fibers Epithelium

39. Bulbourethral gland prostate gland seminal vesicle ampulla urethra b-u gland efferent ducts epididymis vas deferens rete testis

40. The Penis- has two functions: Urination Reproduction

41. The Penis erectile tissue Corpora cavernosa Tunica albuginea Skin Corpus spongiosum Urethra

42. Penis: Erectile Tissue elastic fibers and smooth muscle endothelial cells line cavernous spaces trabeculae

43. The Penis Blood flow to corpus cavernosa and mechanism of erection Helicine artery

44. Mechanism of action of Viagra Penile vascular smooth muscle cell relaxation GTP Viagra (Loss of erection)

45. See, the problem is that God gives men a brain and a penis and only enough blood to run one of them at a time. Robin Williams

46. Semen Semen consists of spermatozoa and secretions of the accessory sex glands, which follow one another in a definite sequence: During arousal: Bulbourethral gland secretes mucous-like secretion which lubricates the urethra At ejaculation: 1. Prostate gland secretion—proteolytic enzyme rich 2. Spermatazoa are ejected 3. Seminal vesicle secretion follows—nutrient rich NB: Spermatozoa comprise only 5% of semen

47. Thank you It’s been great—but it’s time to be going home (my wife’s wondering where I’ve gone!) bon voyage et bonne chance!