Abdomen 4 Flashcards
what forms the large intestine
- caecum
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
blood supply to GIT?
foregut - coeliac trunk T12
midgut - SMA L1
hindgut - IMA L3
Explain the development of midgut
Because the intestines are so long, they herniate out through the abdominal wall into the umbilical cord, twist around the superior mesenteric artery and enter back
What is the term given when the gut contents is protruding from the umbilical ring in a baby? why?
Omphalocele
Usually because rectus abdominis fails to develop properly
Malrotation of the midut
50% due to chromosomal abnormality
If surgical repair is possible, positive prognosis
What is the term given to outpouching of the ileum in babies?
What is the cause of this?
Meckel’s diverticulum
Vitelline duct connects the growing foetus to the yolk sac
The vitelline duct fails to degenerate resulting it in attaching to the ileum leading to the outpouching
Ulceration or bleeding caused
What part of the GIT does the vitelline duct attach to?
ileum
where are the main sites for absorption?
jejunem (mostly) and illeum - 95%
What is the start and end of the jejunum and ileum?
In which quadrant can we find the jejunum and ileum
Duodenojejunal flexure to ileocaecal junction
Jejunum = LLQ
Ileum = RLQ
What is the mesentery?
What does it contain?
Suspends the jejunum and ileum (both intrapeitineal) from the posterior abdominal wall
Contains
Superior mesentaric artery (L1 from abdominal aorta)
Superior mesenteric vein (joins with splenic to form portal)
Lymph nodes, fat and autonomic nerves)
What is the route of the mesentery?
mesentry is attached to posterior abdo wall via roots - oblique course
- Duodenojejunal flexure to sacro-iliac joint
what does the IMV join with?
IMV –> splenic vein –> portal vein to be processed by liver
jejunum and ileum structure differences:
- lumen
- wall
- vasa recta, blood supply
- peyer’s patches: aggregation of lymphatic tissue
- mesentery
What does the large intestine extend from?
What is its main function?
Ileocaecal junction to anus
Water and salt absorption
Label the parts of the colon/ large intestine on the X-ray
where does cecum reside?
next to right illiac fossa, before becoming the ascending colon
where are the Paracolic gutters and clin rel
Lateral to ascending and descending colons - fills up if burst appendix
what is the ileal orifice?
ileocecal valve - entrance to cecum from ileum
where half digested food enters the colon (cecum)
What are features of the colon which help us identify it to the small intestine?
Contains
Haustra - sacculations
Teniae coli - 3 longitudinal bands of muscle
Omental appendices - fat pouches
HOT
Label the diagram of the colon
Where in the colon do we find the boundary between the midgut and hindgut?
Midgut and hindgut is split in the 2/3 transverse colon
what vessel provides the caecum?
ileocolic artery –> branch of SMA
What junction is found in the caecum?
What supplies the caecum?
Where does this artery come from?
Ileocaecal junction
Ileocolic artery which is a branch of the superior mesenteric artery
What is the relationship of the appendix to the peritoneum?
How can its position vary?
Appendix is intraperitoneal = contains mesoappendix
position varies:
What is the relationship of the opening of the appendix to the ileocaecal opening
The orifice of the appendix is inferior to the ileocaecal opening
What artery is appendix supplied by?
Supplied by appendicular artery = branch of ileocolic artery