Chapter 60 - Testis

Question 1

1. The ______ is a prepubic diverticulum of skin that contains the testes, their associated ducts, and the distal portion of the spermatic cords.

Answer 1

• Scrotum

Question 2

2. What structures are contained within the scrotum? (3)

Answer 2

• Testes
• Associated ducts
• Distal portion of the spermatic cords

Question 3

3. The skin of the scrotum contains an unusually high number of what structure?

Answer 3

• Sweat glands

Question 4

4. What is the tunica dartos?

Answer 4

• A layer of connective tissue and involuntary muscle intimately adherent to the scrotal skin.

Question 5

5. What is the function of the tunica dartos?

Answer 5

• To help regulate the testicular temperature, relaxing with heat and contracting with cold.

Question 6

6. The vascular supply to the scrotum originates from the ___________ vessels

Answer 6

• External pudendal

Question 7

7. The nervous supply descends into the scrotum on the outer surface of the ____________ via the _________ nerve.

Answer 7

• Vaginal tunic
• Genitofemoral nerve

Question 8

8. What is the nerve supply of the scrotum?

Answer 8

• genitofemoral nerve

Question 8

9. Lymphatics from the scrotum drain to the _________ nodes.

Answer 8

• Superficial inguinal lymph nodes

Question 9

10. The testes produce _________ and __________

Answer 9

• Spermatozoa
• Hormones

Question 10

11. The long axis of the equine testicle is oriented in which direction?

Answer 10

• Horizontally, raised slightly cranial

Question 11

12. The testicular bursa exists between what 2 structures?

Answer 11

• Testis and epididymis

Question 12

13. What are the 3 parts of the epididymis?

Answer 12

• Head
• Body
• Tail

Question 13

14. The head of the epidymis lies at the (cranial/caudal) pole of the testis and the body is positioned on the (medial/lateral) surface of the testis.

Answer 13

• Cranial
• Lateral

Question 14

15. The tail of the epididymis continues proximally and transitions into what structure?

Answer 14

• The ductus deferens

Question 15

16. What is the tough, inelastic capsule of dense fibrous tissue that covers the testis?

Answer 15

• Tunica albuginea

Question 16

17. What do each of the testicular lobules consist of? What 2 cell types predominate?

Answer 16

• Convoluted seminiferous tubules
• Spermatogonia
• Sertoli cells (sustentacular cells)

Question 17

19. What is the function of Sertoli cells?

Answer 17

• Provide mechanical and nutritive support for the developing spermatozoa

Question 17

18. What is the function of spermatogonia?

Answer 17

• Create spermatozoa

Question 18

20. What hormone stimulates spermatogenesis? Where is that hormone produced?

Answer 18

• Follicle stimulating hormone (FSH)
• The hypophysis

Question 19

21. Over 70% of the parenchyma of the testis is made up of what?

Answer 19

• Seminiferous tubules

Question 20

22. The cells of Leydig (interstitial cells) produce _______ (including an unusually high amount of _______) in response to _____________.

Answer 20

• Androgens
• Estrogen
• Interstitial cell- stimulating hormone

Question 21

23. What is the function of interstitial cell-stimulating hormone (LH analog) in the stallion?

Answer 21

• Induces the cells of Leydig to produce androgens

Question 22

24. What is the source of estrogen in the stallion?

Answer 22

• The cells of Leydig

Question 23

25. Interstitial cell-stimulating hormone is similar or identical to _________ and is produced in the _________.

Answer 23

- Lutenizing hormone - Hypophysis (pituitary gland)

Question 24

26. The seminiferous tubules converge to form the tubules of the ____________, which pierce the tunica albuginea at the dorsocranial border of the testis to become the __________.

Answer 24

- Rete testis - Efferent ductules

Question 25

27. Where do spermatozoa mature?

Answer 25

- In the epididymal duct

Question 26

28. What structures pass through the inguinal canal? (4)

Answer 26

- Spermatic cord - Genitofemoral nerve - External pudendal vasculature - Efferent lymphatic vessels (to superficial inguinal lymph node)

Question 27

29. What are the 3 borders of the internal inguinal ring?

Answer 27

- Caudal edge of the internal abdominal oblique muscle - Rectus abdominal muscle & prepubic tendon - Inguinal ligament

Question 28

30. What is the cranial border of the internal inguinal ring?

Answer 28

- Caudal edge of the internal abdominal oblique muscle

Question 29

31. What is the ventromedial border of the internal inguinal ring?

Answer 29

- Rectus abdominal muscle & prepubic tendon

Question 30

32. What is the caudal border of the internal inguinal ring?

Answer 30

- Inguinal ligament

Question 31

33. What is the external (superficial) inguinal ring?

Answer 31

- A 10-12cm slit in the external abdominal oblique muscle

Question 32

34. The wall of the inguinal canal is lined by ___________ which forms the __________

Answer 32

- Peritoneum - Vaginal tunic

Question 33

35. What are the 2 layers of the vaginal tunic?

Answer 33

- Visceral tunic - Parietal tunic

Question 34

36. The vaginal tunic is derived from what tissue?

Answer 34

- The abdominal peritoneum

Question 35

37. During rectal palpation, where can the vaginal ring be located?

Answer 35

- 10-12cm abaxial to the linea alba and 6-8cm cranial to the iliopectinial eminence

Question 36

38. The diverticulum of the peritoneal cavity between the parietal and visceral tunics is the ___________.

Answer 36

- Vaginal cavity

Question 37

39. What structure guides the fetal testicle into its final position in the scrotum?

Answer 37

- The gubernaculum

Question 38

40. What are the 3 sections of the fetal gubernaculum and where do they connect?

Answer 38

- Cranial: between the testis and the epididymis - Middle: lies between the epididymis and the point at which the gubernaculum penetrates the abdominal wall at the site of the future inguinal canal - Caudal: from the abdominal wall to the scrotum

Question 39

41. What is the proper ligament of the testis?

Answer 39

- Connection between the tail of the epididymis and the testis

Question 40

42. What is the ligament of the tail of the epididymis?

Answer 40

- Connection between the tail of the epididymis to the parietal tunic

Question 41

43. The cranial part of the gubernaculum becomes what?

Answer 41

- The proper ligament of the testis

Question 42

44. What structure connects the parietal tunic to the bottom of the scrotum?

Answer 42

- the scrotal ligament

Question 43

45. The middle part of the gubernaculum becomes what?

Answer 43

- Ligament of the tail of the epididymis

Question 44

48. The mesorchium encloses what structures?

Answer 44

- the neurovascular components of the spermatic cord

Question 44

46. The caudal part of the gubernaculum becomes what?

Answer 44

- Scrotal ligament

Question 45

47. What structures make up the spermatic cord? (5)

Answer 45

- Vaginal tunic - Blood vessels of the testis - Nerves of the testis - Lymphatic vessels of the testis - Ductus deferens

Question 46

49. What is the function of the ductus deferens?

Answer 46

- Stores spermatozoa - Propels spermatozoa from the epididymis to the pelvic portion of the urethra during ejaculation

Question 47

50. The ductus deferens enlarges to form what structure before terminating at the ejaculatory orifices on the colliculus seminalis?

Answer 47

- Ampulla

Question 48

51. What is the genital fold?

Answer 48

- A horizontal sheet of peritoneum lying between the bladder and the rectum which houses the ductus deferens

Question 49

53. The __________ artery and its branch, the ________ artery, constitute most of the vascular supply to the testis, with the ___________ and ________ arteries also contributing

Answer 49

- Testicular artery - Epididymal artery - Deferential - Cremaster

Question 49

52. The ductus deferens is supplied by the ___________ artery, which is a branch of the _________ artery.

Answer 49

- Deferential artery - Umbilical artery

Question 50

54. The testicular artery is a branch of the ___________

Answer 50

- Abdominal aorta

Question 51

55. Vascular drainage from the testis is a convoluted structure called the __________ which eventually coalesces within the abdomen to form into the __________.

Answer 51

- Pampiniform plexus - Testicular vein

Question 52

56. The right testicular vein usually joins the ____________ while the left testicular vein usually joins the ___________.

Answer 52

- Caudal vena cava - Left renal artery

Question 53

57. Contraction of the __________ muscle retracts the testis

Answer 53

- Cremaster

Question 54

58. The cremaster muscle is a slip of what larger muscle?

Answer 54

- The internal abdominal oblique muscle

Question 55

59. How can monorchidism be confirmed?

Answer 55

- By an HCG stimulation test or testing for Anti-Mullerian hormone after the contralateral testical has been removed

Question 56

60. Is monorchidism is more likely to be the result of testicular degeneration or atresia?

Answer 56

- Testicular degeneration

Question 57

61. The gubernaculum is innervated by what?

Answer 57

- The genitofemoral nerve

Question 58

62. Which cryptorchid testicle is more likely to be abdominally retained?

Answer 58

- The left (tends to be slightly larger?)

Question 59

63. Which horse breeds are at higher risk of inguinal herniation? (5)

Answer 59

- Andalusion - Draft breeds - Standardbreds - Saddlebreds - Tennessee Walking Horses

Question 60

64. Torsion of the spermatic cord has most commonly been reported in what breed?

Answer 60

- Standardbreds

Question 61

65. What is a hydrocele or vaginocele?

Answer 61

- An abnormal collection of serous fluid between the visceral and parietal layers of the vaginal tunic.

Question 62

66. What is a hematocele? What are its usual causes?

Answer 62

- A collection of blood within the vaginal cavity - Testicular or scrotal trauma, may occur as an extension of hemoperitoneum

Question 63

67. What is a varicocele?

Answer 63

- An abnormally distended and tortuous pampiniform plexus

Question 64

68. What may be the effects of a varicocele on the testicle? (4)

Answer 64

- Impaired drainage of blood - Increased scrotal temperature - Testicular hypoxia - Elevated testicular pressure

Question 65

69. What are the germinal testicular tumors of the horse? (4)

Answer 65

- Seminoma - Teratoma - Teratocarcinoma - Embryonic carcinoma

Question 66

70. What are the non-germinal testicular tumors of the horse? (2)

Answer 66

- Sertoli cell tumor - Leydig cell tumor

Question 67

71. What is the primary clinical sign of testicular neoplasia?

Answer 67

- Testicular enlargement

Question 68

72. What are the 1st and 2nd most common testicular tumors of the horse?

Answer 68

- Seminoma - Teratoma

Question 69

73. What is the difference between true hermaphrodites and pseudohermaphrodites?

Answer 69

- True hermaphrodites have both testicular and ovarian tissue while pseudohermaphrodites have only gonads of 1 sex

Question 70

74. Where do ruminant testicular lymphatics drain to?

Answer 70

- Medial iliac lymph nodes