urino-genital anatomy 2

Question 1

what is the inguinal canal

Answer 1

potential space between layers of the abdominal wall muscles that communicates with an external pouch

Question 2

what is the deep inguinal ring

Answer 2

gap in internal abdominal oblique muscle

Question 3

superficial inquinal ring

Answer 3

slit in external abdominal oblique muscle

Question 4

vaginal ring

Answer 4

opening of peritoneal cavity into inguinal canal

Question 5

what animals are at greater risk of inguinal herniation

Answer 5

pig and rabbit due to deep inguinal ring is superimposed over the superficial inguinal ring

Question 6

development of testes

Answer 6

start in abdomen at caudal pole of kidneys
development of sperm hindered at body temp so testes must be descend through inguinal canal to cooler scrotum - aided by gubernaculum

Question 7

anatomy of scrotum

Answer 7

sac of skin that encloses testes and their coverings
median septum separates testes within scrotum
extensive sebaceous and sweat glands

Question 8

blood supply to scrotum

Answer 8

branch of external pudendal artery and vein

Question 9

layers of the testis

Answer 9

skin
tunica dartos
spermatic fascia - external spermatic, cremasteric, intenral spermatic
parietal peritoneum
visceral peritoneum

Question 10

what is the spermatic cord

Answer 10

contains ductus deferens and testicular vein/artery in peritoneal fold - continuous with vaginal tunic

Question 11

which artery conveys blood direct to testis

Answer 11

testicular artery

Question 12

what does the testicular vein being arranged in a mesh allow

Answer 12

cooling of arterial blood to testes via heat exchange with venous blood from testis

Question 13

spermatic sac

Answer 13

consists of vaginal tunic with closely adherent internal spermatic fascia and cremasteric fascia
attached to scrotum via scrotal ligament

Question 14

what must happen to spermatic sac in a closed castrate

Answer 14

scrotal ligament must be broken to free up the testis

Question 15

difference between open and closed castration

Answer 15

whether abdominal cavity is opened or remains closed during procedure

Question 16

anatomy of castration

Answer 16

scrotum incised to remove testes and left open to drain
haemostasis of artery and vein achieved via pressure/ clotting rather than ligatures
inflammatory fluid passing out usually prevents contamination of peritoneal cavity
superficial inguinal ring not superimposed on deep inguinal ring therefore herniation unlikely

Question 17

requirements for open or closed castration

Answer 17

dogs > 25kg = open
dogs < 25kg = open or closed
inexperienced surgeon = open

Question 18

open castration

Answer 18

layers incised
skin - testes pushed out of scrotum into inguinal area made through normal skin which heals well and therefore can be sutured
spermatic fascia
vaginal tunic - opened peritoneal cavity
testis freed by breaking ligament of the tail of the epididymis
spermatic cord ligated

Question 19

closed ligation

Answer 19

layers incised - inguinal skin and external spermatic fossa only
spermatic sac remains - cremasteric fascia, internal spermatic fascia, vaginal tunic (peritoneum)
spermatic sac freed from scrotum by breaking scrotal ligament
neck of spermatic fascia ligated prior to transection
peritoneal cavity never entered and remains closed

Question 20

anatomy of penis

Answer 20

root attached to ischium - 2 crura and bulb
shaft of penis - erectile tissue = corpus cavernosum and corpus spongiosum - urethra
free part of penis - lies within prepuse - tip enlarged

Question 21

functional anatomy of corpus spongiosium

Answer 21

encloses urethra from pelvis to tip of penis
expansion near pelvis = bulb of penis/ urethral bulb
expansion at tip = glans penis

Question 22

functional anatomy of the corpus cavernosum

Answer 22

2 fibrous crura attached to ischium = lie on either side of of urethra and then fuse (except in dog) and pass dorsal to urethra
2 types of corpus cavernosum = musculocavernous = smooth muscle with large cavernous space - man and horse
fibro-elastic = fibrous and elastic tissue arranged in a sigmoid flexure with small cavernous spaces - ruminants and pig

Question 23

arterial blood supply to penis

Answer 23

branch of internal pudendal artery curves around ischiatic arch and sends branches deep into erectile tissue at root of penis
continues along dorsal surface of penis outside tunica albuginea

Question 24

venous blood supply of penis

Answer 24

erectile tissue only trained at root of penis via internal pudendal vein
in horse - massive drainage from body of penis into external pudendal vein
no vascular connections between the corpus

Question 25

muscles of penis

Answer 25

retractor penis muscle
ischiocavernosus
bulbospongiosus