Intestinal Anatomy Flashcards
Which is the only segment of the dog intestine that is easily palpated?
The descending colon
Does the ileum open directly into the caecum in the dog and cat?
No
Which structures are supplied by the caudal mesenteric artery in the dog?
Descending colon and cranial rectum
What structures are supplied by the celiac artery in the dog?
The liver and part of the stomach
What structures are supplied by the cranial mesenteric artery in the dog?
SI, cecum, mid part of colon
What structures are supplied by the internal pudendal artery in the dog?
Caudal rectum and anus
Which structure can be used to demarcate the beginning of the ileum from the jejunum?
The antimesenteric ileal branch
In which species are the mesenteric lymph nodes clustered around the root of the mesentery?
The dog
Which anal sphincter is under voluntary control and which is not? What structure occurs between these two sphincters?
The internal anal sphincter is made of smooth muscle and is not under voluntary control
The anal sacs occur between the sphincters
The external anal sphincter is skeletal muscle, and may be controlled voluntarily
Which two species have only one duodenal papilla, and therefore just one pancreatic duct?
The sheep and the cat
In which species does the major duodenal papilla contain ONLY the bile duct?
Cow and pig
Which species have two duodenal papillae and the major duodenal papilla contains both a pancreatic and bile duct?
Dog, horse, ~ bird
How many duodenal papillae does the bird have?
Three
Which species have only 1 pancreatic duct?
Cat, pig, sheep, cow
In the horse, does the pancreas lie to the L or the R of the median plane?
Left
What is the name for the notch in pancreatic tissue that allows the portal vein to pass?
Annulus pancreatis
In which quadrant of the horse abdomen do the jejunum and ileum sit? Why?
Left caudal, between the cecum ventrally and the small colon dorsally
The large caecum is heavier, occupies the ventralmost position
In the horse, what does the ileum open into?
The caecum at the ileocaecal orifice
What forms the ileal papilla in the horse? Is it known by any other name?
Ileal papilla = ileocaecal valve
Projection of mucosa that is highly vascular and muscular
What is the function of the ileal papilla in the horse?
Functions to occlude the ileum and ‘squirt’ portions of fluid ingesta through into the caecum. Valve tone prevents retrograde ingesta movement and bacterial inoculation of ileum
In what quadrant of the horse abdomen does the duodenum sit?
Left caudo-dorsal
What shape is the bovine pancreas?
Bovine - vaguely quadrilateral
What two structures pass through the incisura pancreatis in the cow?
The portal vein
The cranial mesenteric artery
Where in the abdomen is the cow pancreas?
Very dorsal - ventral to the right kidney, caudal to the liver
Which lobe of the cow pancreas is closest to the duodenum?
The right
What shape is the pancreas in the pig? Where in the abdomen is it located?
Roughly tri-radiate
Dorsal, caudal to the stomach, mostly L of the median plane
Where in the abdomen is the jejunum of the pig?
Right dorsal region, some coils may lie on abdominal floor
What is the approximate length of the horse large intestine?
7.5 - 8m
Which two segments of horse large intestine constitute the great colon?
The ascending + transverse colon
What is the position of the equine caecum in the abdomen?
right ventral
Regarding the base of the horse caecum, the greater curvature is _____ and the lesser is ______ . (directional)
Regarding the base of the horse caecum, the greater curvature is dorsal and the lesser is ventromedial .
Which curvature bears the openings of the horse caecum, and what are their names?
The lesser curvature of the horse caecum bears the ileocaecal orifice and the caecocolic orifice
How many taenia does the horse caecum bear?
4
How many taenia does the left ventral colon bear?
4
How many taenia does the right ventral colon bear?
4
How many taenia does the pelvic flexure bear?
1
How many taenia does the left dorsal colon bear?
3
How many taenia does the right dorsal colon bear?
3
How many taenia does the transverse colon bear?
2
How many taenia does the small colon bear?
2
What is the correct order of ingesta progress from caecum to small colon, including the flexures
Caecum > right ventral colon > sternal flexure > left ventral colon > pelvic flexure > left dorsal colon > diaphragmatic flexure > right dorsal colon > transverse colon > descending
The sternal flexure occurs between which two colon segments?
Right ventral and left ventral
The pelvic flexure occurs between which two colon segments?
Left ventral and Left dorsal
The diaphragmatic flexure occurs between which two colon segments?
The left dorsal and right dorsal
What three factors of the pelvic flexure predispose it to impaction?
Sudden change in calibre (narrower)
Sudden change in direction
Decrease in fluidity of ingesta
What is the ileocaecal fold?
A section of mesentery between the ileum and caecum in a horse
What conformation does the small colon of the horse take?
Coil shape - supported by long mesentery
What are the three most common sites for impaction in the horse?
Pelvic flexure
Base of caecum
Terminal end of right dorsal colon
Which vessels supply the intestines in the horse?
The cranial mesenteric artery - majority
The caudal mesenteric artery - descending colon and rectum
Which section of the cow intestine forms the centrifugal and centripetal loops?
The ascending colon
Describe the descending colon of the cow
Straight except for small sigmoid deviation
How many taenia does the pig caecum have?
Three
Which part of the pig intestine is coiled in cone-shape? Are the centripetal turns on the outside or inside? What does centripetal mean?
Ascending colon
Centripetal = clockwise. These turns on the outside.
Which part of the intestinal coil in the pig has taenia? how many?
The centripetal part - has two
Describe the caecum of the bird
Paired caeca attached to the ileum via two ileocaecal folds.
Describe the pancreas of the bird.
Elongated U shape, sits within the loop of the duodenum.
