horse anatomy

  1. What is the shape of the right kidney and where is it located in the horse?
    heart shaped; retroperitoneal and cranial to liver, ventral to descending duodenum, pancreas and base of cecum
  2. What is the shape of the left kidney and where is it in the horse?
    flat/bean shaped; ventral to T17-L2 thus caudal to right and less retroperitoneal
  3. Are either of the kidneys palpable per rectum?
    the caudal pole of the left kidney may be palpable
  4. Where is the lienorenal ligament?
    connects left kidney to the spleen
  5. What is the internal structure of the kidneys in the horse?
    unipyramidal aka fused pyramids with a common renal crest
  6. What is the renal sinus?
    medial indentation in the kidney around the hilus that has fat
  7. What is unique about the horse's urine?
    physiological albuminuria- due to the presence of glands in the renal pelvis, the horse produces mucous making the urine viscous and cloudy
  8. Where does the renal artery originate?
    comes directly from the aorta, is relatively large and can have 2 or more branches going in to renal surfaces
  9. Where are the adrenal glands in the horse?
    medial and cranial on either kidney
  10. What is the shape of the mare's pelvis? in the stallion?
    round and wide in the mare with flat and horizontal floor to accommodate parturition; no undue curvatures or turns. In the mare the pelvis is triangular
  11. What ligament is well developed in the pelvic region of the horse?
    the sacrotuberous ligament
  12. Describe the structure and location of the scrotum in the horse
    globular with no neck, it tightly encloses the testis so they don't move. the scrotum sits high b/w the thighs so you cannot see it via caudal view; sparse hair with median scrotal raphe between
  13. What artery supplies the scrotum?
    external pudendal artery
  14. What are the tissue layers that comprise the horse scrotum?
    • 1. skin
    • 2. tunica dartos = fibroelastic tissue and smooth m.
    • 3. fascial sheaths form inner and 3rd layer
  15. What attaches the tunica dartos to the spermatic sac aka the vaginal tunic?
    scrotal ligament
  16. from where does the external spermatic fascia come?
    external abdominal oblique muscle
  17. from where does the cremasteric fascia and muscle come?
    internal abdominal oblique muscle
  18. To what does the internal spermatic fascia adhere?
    to the vaginal tunic which is continuous with the peritoneal cavity
  19. What is the nerve supply to the scrotum in the horse?
    innervation from spinal nerves L2 and L3 with some help from preputial and scrotal branches of the pudendal n.
  20. How do the testis in the horse appear?
    oval or round, with a horizontal long axis and indistinct mediastinum
  21. Where is the epididymis?
    lays on the dorsal aspect of the testis with the tail projecting more caudally beyond testis pole
  22. Which ligament is well formed in the mail sex organs?
    the ligament of the tail of the epididymis
  23. What does the proper ligament connect?
    attaches the tail of the epididymis to the caudal pole of the testis
  24. Where is the testicular and spermatic aa?
    cranial border of the spermatic cord with tortuous branches on the surfaces
  25. What is the pampinaform plexus?
    veins surrounding the testicular artery with valves to prevent backflow
  26. Where is the testicular vein free?
    up in the inguinal canal
  27. What vessels run alongside the ductus deferens?
    cremasteric artery and vein
  28. What is open castration?
    scrotal skin and vaginal process are incised
  29. what is closed castration?
    scrotal skin is incised, transect distal to a ligature- remove testis; skin and external spermatic fascia are separated from cremasteric fascia
  30. How do you sterilize a horse?
    open vaginal process, ligature placed between tail and body of the epididymis and dectus deferens; remove tail tissue. testis remains thus libido remains
  31. What are the most developed accessory sex glands int he horse?
    ampulla of the ductus deferens
  32. What accessory sex glands are not present in the horse?
    none, all are present
  33. What is the ejaculatory duct and how does it run?
    It's short and opens on the side of the seminal colliculus; it is shared by the ampulla of the ductus deferens and the ipsilateral vesicular gland
  34. What is the seminal colliculus?
    dorsal mound-like feature of the initial portion of the urethra
  35. What and where are the vesicular glands
    true vesicles that are pear shaped sacs on the dorsal bladder in the genital fold; accessory sex glands
  36. What part of the prostate gland is present in the horse and where?
    only the body, it's discrete and compact across the neck of the urinary bladder and the beginning of the pelvic urethra
  37. What is the structure of the prostate glands?
    obvious lobulation with isthmus to separate left from right lobes; there are up to 20 ducts that open on either side of the seminal colliculus
  38. What is the structure of the bulbourethral gland and how is it situated?
    it's small oval on the dorsal end of the pelvic urethra, covered by bulboglandularis muscle; has 6-8 ductus that open in to the dorsal urethra
  39. Describe the pelvic urethra
    direct and non-demarcated continuation of the neck of the urinary bladder with its dorsal surface covered by the accessory sex glands
  40. How big is the penis typically?
    about 45 cm when not erect with 5 cm diameter
  41. What are the 2 components of the penis?
    corpus spongiosum around the pelvic urethra and corpus cavernosum made of smooth muscle in the trabeculae; they fuse in to the corpus aka the dorsal penis that extends to the tip.
  42. What is the purpose of the corpus cavernosum?
    it has cavernous spaces that allow for expansion in both length and diameter when erect
  43. What is tonic contraction and what controls it?
    this refers to the smooth muscles that hold the penis within the prepuce under sympathetic innervation
  44. What system controls erection?
    the parasympathetic system
  45. Where does the corpus spongiosum sit and what surrounds it?
    spongiosum lays ventral to cavernosum outside the tunica albuginia...its enclosed throughout by the bulbospongiosus muscle
  46. What is the glans penis?
    enlarged portion, erectile tissue is extension of the corpus spongiosum capping the distal end of the corpus cavernosum penis
  47. what are the 3 main parts of the penis?
    • 1. corona glandis linked to
    • 2. dorsal process via
    • 3. collum glandis aka neck
  48. What is the shape of the free part of the penis?
    blunt, rather than pointed
  49. Where is the urethral process?
    this is the end of the urethra that is surrounded by fossa glandis
  50. What is the urethral sinus?
    this is a dorsal diverticulum in the urethra that contains shmegma and may accumulate dirt that solidifies in to a bean...makes for colic symptoms in horse
  51. What muscles protract and retract the prepuce?
    the caudal and cranial preputial muscles respectively; not present in the stallion
  52. What are the 3 main arteries that supply blood to the penis?
    • artery of the penis (internal pudendal)
    • obturator artery
    • external pudendal artery (equine peculiarity)
  53. what are the 3 branches of the artery of the penis?
    • deep artery of the penis- supplies erectile tissue and root of the penis
    • dorsal artery of the penis- supplies dorsal surface
    • artery of the bulb of the penis
  54. What vein drains the body of the penis?
    major vein of the external pudendal vein
  55. What vein drains the root of the penis?
    the internal pudendal vein
  56. What happens upon abduction of the hindlimbs during breeding?
    muscles stretch and veins constrict
  57. What vessels supply and drain the prepuce?
    dorsal artery and vein via branches of caudal superficial epigastrics
  58. What lymph nodes drain the hindquarters?
    medial iliac lymph nodes; efferents sent via deep inguinal lymph nodes
Card Set
horse anatomy
kidney, genitalia, hind limb