Lecture 18: GI II Flashcards
Cecum
-blind-ended pouch
-covered in peritoneum, but no messentery
valve of cecum
ileocecal valve (ileocolic)
**1 way valve
Vermiform Appendix
-8-10cm long
-Aggregations of lymphoid tissue
-No longer necessary - more trouble than function
-suspended by the mesoappendix
variable positions of vermiform appendix
retrocecal, retrocolic, pelvic
McBurney’s point
point on anterior abdominal wall that is the lateral 1/3 of the distance from the ASIS to umbilicus
Four parts of the colon
-Ascending (R. upper)
-Transverse
-Descending (L. upper)
-Sigmoid (pelvic)
2 flexures of the colon
Left (splenic) colic flexure & right (hepatic)colic flexure
3 features of the colon
-Teniae coli
-Haustra
-Epiploic
muscular components of the colon
-Taeniae coli
-Haustra
Taeniae coli
-3 longitudinal bands of smooth muscle that run along the outer layer of the entire colon
Haustra
-pouches in the wall of the colon
-created by muscle tone in taeniae coli
-permit expansion and elongation of the colon
Peritoneal coverings of the colon: Mesocolon
-Complete covering
-Partial covering
-Mesoappendix
Mesocolon: Complete covering
transverse & sigmoidal mesocolons (intraperitoneal)
Mesocolon : Partial covering
ascending, descending & rectal mesocolons (retroperitoneal)
Mesocolon: Mesoappendix
connectsappendix to ileum and cecum
The cecum has all these features except
1. Valve
2. Pouch
3. Mesenteric attachment
4. Peritoneal attachment
- Mesenteric attachment
where does the midgut transfer to the hindgut
Distal 1/3 of transverse colon
Large intestine BS: SMA branches into
ileocolic, right colic and middle colic arteries
Large intestine BS: IMA branches into
Left colic, sigmoidal and superior rectal ateries
Large Intestine BS: marginal artery of drummond
anastomoses between right, middle and left colic arteries
purpose of margianal artery of drummond
key for collateral circulation or alternative supply
if the celiac artery was blocked, what part of the large intestine would be affected?
none
parts of the pancreas (5)
- Tail
- Body
- Neck
- Head
- Uncinate process
Large Intestine venous drainage
-Splenic vein
-SMV
-IMV
what does the splenic vein drain
spleen, lower esophagus, part of stomach and pancreas
where does the SMV join the splenic vein
posterior to the neck of the pancreas
what does the SMV drain
areas supplied by the SMA
-iliocecum, left colic, middle colic
SMV
-ascending in root of messentery
-pass to anterior 3rd part duodenum
splenic vein
-hilum of spleen - posterior to tail and body of pancreas
-joins SMV
IMV
-ascends on the left posterior abdominal wall
-joins splenic vein posterior to pancreas
what does the IMV drain
areas supplied by the IMA
-Left colic, Sigmoidal, superior rectal
Hepatic portal vein created by
-splenic vein and SMV unite
hepatic portal vein carries
nutrients from digestive tract to the liver
Portosystemic obstruction
result of obstructed venous return to the liver
possible causes: thrombosis, liver cirrhosis, heart failure
