1. Reproduction
Chapter 27

2. Male Reproductive System
Reproductive organs
Testis
Scrotum
Reproductive tract
Epididymis
Vas Deferens
Spermatic cord
Accessory glands & organs
Seminal vesicles
Prostate gland
Bulbourethral gland
Penis

3. Gamete Production Testes Spermatogenesis- VERY temperature sensitive
Spermatozoa (sperm)
~ million/ day
Production begins at puberty
Spermatogenesis- VERY temperature sensitive
Optimal temperature ~3-4C below body temp

4. Pendulous Testes

5. Scrotum Bi-chambered external pouch of skin Function
Houses testes
Protects testes
Regulates testicular temperature
Scrotum modifications for temperature regulation & protection
Low insulation- sparse hair & thin skin
Sweat glands
Vascularization- countercurrent blood flow
Musculature
Ennervation

6. Low Insulation
Little insulating fat
Sparse hair
Sweat glands

7. Musculature Dartos muscle (tunic) Cremaster muscle
Muscle inserting into scrotal skin
Contraction tenses skin of scrotum & raises testis
wrinkling
Cremaster muscle
Surrounds testis
Contraction pulls testis closer to body
Cold- contraction
Warm- relaxation

8. Vascularization Pampiniform plexus Countercurrent blood flow
Cool venous blood surrounds incoming arteries
Actively cools incoming blood & warms outgoing blood
Testes always surrounded by cool blood
Testes

9. Varicocele Most common curable cause of infertility
Equivalent of varicose veins

10. Scrotum Nerves
Behavioral protection

11. Testis Paired gonads inside of scrotum Surrounded by tunic Function
Tunica albuginea
Function
Spermatogenesis- sperm formation
Hormone production
Androgens- testosterone

12. Tunica albuginea
“White Coat”

13. Testis Structure Seminiferous tubules Rete testis
Sertoli cells
Rete testis
Interstitial (Leydig) cells

14. Seminiferous Tubules Actual site of spermatogenesis 800+ coiled tubes
Maximizes surface area
Bulk of testes tissue

15. Figure: 17-02
Title:
The internal structure of the testis and epididymis.
Caption:

17. Figure: 17-03b
Title:
The stages of spermatogenesis in the wall of a seminiferous tubule.
Caption:
Bottom: As the cells that will become sperm develop, they are pushed from the outer wall of the tubule to the central canal.

19. Sertoli Cells Lots tight junctions in cells near basement membrane
Form blood testes barrier
Protects from pathogens, mutagens, immune cells

20. Spermatogenesis & Androgen Production Stimulated by Brain

22. Interstitial (Leydig) Cells
Located between seminiferous tubules
Site of androgen production
Surrounded by capillaries
Stimulated to produce by increased levels of testosterone by Leuteinizing Hormone

23. Interstitial (Leydig) Cells

24. Interstitial (Leydig) Cells

26. Testosterone Levels

27. Testosterone Levels

28. Testosterone Levels

29. Sperm Path
Male reproductive tract continuous- Isolates sperm

30. Rete Testis Located within the testis
Site of merging seminiferous tubules exiting from testes
Common pathway for exiting sperm

31. Male Reproductive Tract

32. Epididymis Testicular cap Single coiled tubule
6M long
Receives sperm from rete testis
Function
Secretes/absorbs nourishing fluid
Recycles damaged spermatozoa
Stores spermatozoa
Up to 2 weeks
Allows time for maturation

33. Epididymis

34. Epididymis

35. Tunica Vaginalis Surrounds testes & epididymis
Allows free movement of testes inside of scrotum

36. Vas Deferens Aka Ductus Deferens
Single tubule carries sperm from epididymis into abdominal cavity
45 cm long
Muscular tube
Passes thru inguinal canal
Connects to urethra at prostate

37. Vas Deferens

38. Spermatic Cord Tissue located within the inguinal canal
Combination of tissues
Vas deferens
Pampiniform plexus
Testicular tissue
Arteries & nerves
Muscle

40. Inguinal Canal

41. Testis Torsion

43. Accessory Glands
Seminal vesicle
Prostate
Bulbourethral gland

44. Accessory Glands Secrete seminal fluid
Nourish, activate & protect sperm
Semen (seed)
Glandular secretions (99%) & sperm (1%)
~2-5 mls per ejaculation
~ million sperm per ml of ejaculate
million per ejaculation
50 reach oocyte

45. Seminal Vesicle Paired elongate glands
Located posterior & inferior to bladder
Secretes (60% semen)
Fructose
“sugar”
Energy source
Prostaglandins
Activate sperm motility
Stimulate contractions of female reproductive tract
Fibrinogen
Clotting factors
Slows sperm

46. Prostate Large solid single gland Located at base of bladder
Houses prostatic urethra
Secretes (20-30%)
Enzymes
Aid in activating sperm motility
Antibiotic
Mucus degradation
Alkaline fluid
Neutralize female reproductive tract
Citric acid, proteolytic enzymes
Antioxidants
???secretions of unknown function

48. Prostate Cancer Most common cancer in men
3rd most common cause of death in men
Disease of well developed nations
Diet & lifestyle
High fat diet
High testosterone levels
Cadmium exposure
Low rates in Japanese & vegetarians
By age 80 70% men will have it

51. Bulbourethral Gland Small paired gland
Located at the base of the penis
Secretes alkaline mucus
Neutralize urinary acids
Lubrication

53. Penis Copulatory & excretory organ Excretory Copulatory Penile urethra
Carries urine & sperm
Copulatory
3 cylindrical masses or erectile tissue
2 corpora cavernosa (rt & lt)
Corpus spongiosum

54. Corpora Cavernosa Right & left Primary erectile tissue
Paired superior masses
Provides the majority of rigidity & length
Pulls urethra taught by pushing glans
Crus
posterior expansions
“anchor” tissue against pelvic bone

55. Corpora Cavernosa

56. Corpora Cavernosa

58. Sinusoids & Trabeculae
Smooth muscle holds closed
Vasoconstriction

59. Rich Blood Supply

60. Corpora Spongiosum Inferior mass Contains Penile urethra Glans
Secondary erectile tissue
Contains Penile urethra
Glans
Anterior expansion
Bulb of penis
Posterior expansion
Prepuce
Folds of skin covering glans

61. Houses Penile Urethra

62. Prepuce
Protects
Produces smegma
Waxy substance

63. 2300 BC

65. Male-female Comparison
Penis
Corpora cavernosa
Corpora spongiosum
Prox shaft of penis
Prostate
Bulbourethral glands
Scrotum
Clitoris
Corpora cavernosa
Corpora spongiosum
Labia minora
Paraurethral glands
Grtr vestibular gland
Labia Majora