C11 - The hindgut of carnivores and horses, blood supply and innervation

Question 1

Define hindgut

Answer 1

• The caudal portion the the embryonic gut which develops into the colon and the rectum​
• Begins at the cecum
• Ends at the anus

Question 2

Give the portions of the hindgut

Answer 2

1. Cecum (​Right side of the abdominal cavity, except from in pig)
2. Colon
3. Rectum (Partly inside, partly outside the abdomen)

Question 3

Colon

Dog

Answer 3

• Colon ascendens
  
  • ​Shortest of the three segments
  • Lateral: duodenum descendens and right lobe of pancreas
  • Medial: root of the mesentery
• Flexura coli dextra
• Colon transversum
  
  • ​Right → left, passes between stomach and a. mesenterica cranialis
  • Th12 level
• Flexura coli sinistra
• Colon descendens
  
  • ​Extends to the pelvic inlet, continued by the rectum
  • Longest of the three segments
  • Lies dorsally in the left half of the abdominal cavity
  • Related medially to duodenum ascendens: plica duodenocolica
• Location: dosal in the abdomen

Question 4

Colon

Horse

Answer 4

• Colon ascendens [Colon crassum] (Loop fromed by the colon ventrale and colon dorsale, which bends aronud to the left side)
  
  • Colon ventrale dextrum (Cecum → flexura sternalis, 4 tenia and haustra)
  • Flexura sternalis [=flexura diaphragmatica ventralis]
  • Colon ventrale sinistrum (Flexura sternalis → flexura pelvina, 4 tenia and haustra)
  • Flexura pelvina
  • Colon dorsale sinistrum (Flexura pelvina → flexura diaphragmatica
  • Flexura diaphragmatica [=flexura dorsalis]
  • Colon dorsale dextrum (Terminal part of colon crassum, joins colon transversum, 3 tenia)
  • Ampulla coli (Dilatation of colon dorsale dextrum)​
• Colon transversum
• Colon descendens [Colon tenue] (Flexura coli sinistra → rectum)
• Teniae coli
• Haustra coli
• Everything is attached to the right side
• Only tenia and haustra on the ventral portion
• Can hold 120 liter

Question 5

Colon

Horse: distribution of haustra & tenia

Answer 5

• Colon ascendens:
  
  • Colon ventrale dextrum: 4 tenia
    
    • Tenia libera medialis
    • Tenia libera lateralis
    • Tenia mesocolica medialis
    • Tenia mesocolica lateralis
  • Colon ventrale sinistrum: 4 tenia
    
    • Tenia libera medialis
    • Tenia libera lateralis
    • Tenia mesocolica medialis
    • Tenia mesocolica lateralis
  • Colon dorsale sinistrum: 1 tenia
    
    • Tenia mesocolica
  • Colon dorsale dextrum: 3 tenia
    
    • Tenia libera medialis
    • Tenia libera lateralis
    • Tenia mesocolica
  • Ampulla coli: 3 tenia
• Colon descendens:
  
  • 2 tenia
    
    • Tenia libera
    • Tenia mesocolica

Total: 17????? riktig?

Question 6

Caecum

Dog and horse

Answer 6

• Basis caeci (Dorsal dilation of cecum, eq)
• Corpus caeci
• Apex caeci
• Curvatura caeci major
• Curvatura caeci minor
• Teniae caeci (eq, su) (Bands of cecum)
  
  • Tenia dorsalis (Ø su)
  • Tenia ventralis
  • Tenia medialis
  • Tenia lateralis
• Haustra caeci (eq, su) (Sacculations of the cecum between the teniae and between the plica semilunares)
• Ostium caecocolicum (Opening between cecum → colon)
• Valva caecocolica (eq)
• M. sphincter caeci (ca, bo, su)
• Plica iliocolica (Attaches to tenia dorsalis)
• Plica caecocolica (C**olon ventrale dextrum → tenia lateralis of the caecum)
• Dog:
  
  • No haustra, no tenia
  • Right side, L2-L4
  • Caudal directed
  • Attached to ileum and colon ascendens by peritoneal folds
  • Communicate with colon ascendens at the ostium ileocaecolicaum
• Horse:
  
  • Location in horse:
    
    • Right dorsal part of the abdominal cavity
    • Most dorsal part: basis caeci​
    • Basis caeci extends from pelvic inlet to rib 14/15
    • Dorsally: attaches to fascies ventralis of right kidney and right lobe of the pancreas
    • Left surface of basis caci is attached to the root of the mesentery
  • Haustra/tenia: 4
  • Can hold 30-50 liter

Question 7

Caecum

Give the interspecies differences

Answer 7

• Tenia caeci (eq, sus)
  
  • Tenia dorsalis (ø sus)
  • Tenia ventralis
  • Tenia medialis
  • Tenia lateralis
• Haustra caeci (eq, sus)
• Valva caecolica (eq)
• M. sphincter caeci (ø eq)
• Ca: ø haustra & tenia
• Ru: ø haustra & tenia
• Eq: 4 haustra & tenia
• Su: 3 huastra & tenia

Question 8

Rectum

Dog and horse

Answer 8

• Ampulla recti (enlargement of terminal part)
• Follows colon into the pelvic cavity, terminates at canalis analis
• Pelvic part of large intestines
• Most is covered with peritoneum

Dog:

• Short
• L7 level
• enters the pelvic cavity ventral to sacrum
• In the retroperitoneal part of the pelvic cavity: ampulla recti
• Outer muscle layer of rectum: m. retrococcygeus

Horse:

• Peritoneal cover is last → retroperitoneal tissue
• No more sacculation
• Amulla coli = canalis analis
• M. retrococcygeus deep from long muscle layer of the rectum

Question 9

Bloodsuply of the large intestines

Dog

Answer 9

• Caecum: a. ileocolica → a. caecalis
• Colon ascendens:
  
  • a. ileocolica → r. colicus
  • a. mesenterica cranialis → a. colica dextra
• Colon transversus: a. mesenterica cranialis → a. colica media
• Colon descendens:
  
  • a. mesenterica caudalis → a. colica sinistra
  • a. colica media
• Rectum: a. mesenterica caudalis → a. rectalis cranialis

Question 10

Blood supply of the large intestines

Horse

Answer 10

• Cecum:
  
  • A. ileocolica → a. caecalis medialis et lateralis
• Colon ascendens:
  
  • Colon ventrale: a. ileocolica → r. colicus
  • Colon dorsale: a. mesenterica cranialis → a. colica dextra
• Colon transversus:
  
  • A. mesenterica cranialis → a. colica media
• Colon descendens:
  
  • A. mesenterica caudalis → a. colica sinistra
• Rectum:
  
  • A. mesenterica caudalis → a. rectalis cranialis

Question 11

Innervation

Answer 11

• Sympathetic:
  
  • Decreased activity
  • Ggl. & plexus mesentericus cranialis
  • Ggl. & plexus mesentericus caudalis
• Parasympathetic:
  
  • Increased activity
  • Vagal nerves: supply intestines to the junction between colon transversus and colon descendens
  • Pelvic nerves: supply colon descendens and rectum