intestines Flashcards
what is the alimentary tract ?
- intestines
- bowels / guts
what are the 3 parts that make up the small bowel ?
- duodenum = retroperitoneal
- jejunum = intraperitoneal
- ileum = intraperitoneal
what part of the abdomen do the jejunum + ileum occupy ?
- jejunum = upper 2/5
- ileum = lower 3/5
what structures make up the large bowel ?
- cecum = retroperitoneal
- ascending colon = retroperitoneal
- transverse colon = intraperitoneal
- descending colon = retroperitoneal
- sigmoid colon = intraperitoneal
- rectum
- anal canal + sphincter
where does the foregut end ?
1/2 down second part of duodenum
where does the midgut end ?
2/3 down the transverse colon
where does the hindgut end ?
halfway down the anal canal
what does intraperitoneal mean ?
they have mesentrys = greater mobility
what mesentery supports the transverse colon ?
the transverse mesocolon
what mesentery supports the ileum + jejunum ?
the mesentery
what mesentery supports the sigmoid colon ?
the sigmoid mesocolon
where does the root of the mesentery start / end ?
- root is from posterior abdominal wall starts at duodenojejunal flexure
- ends in the ileocecal junctions
what is a volvulus ?
a twist in the small intestine
obstructs vessels in the mesentery
how long are the small intestines ?
6 m
what is absorbed at each site of the small intestines ?
- duodenum = iron
- jejunum = folic acid
- ileum = vitamin B12 + bile salts
what moves chime through the small intestines ?
- persitaltic + segmentation movements
what is the plicae circulares ?
series of large folds in small intestine
why does the duodenal glands secrete an alkaline solution ?
to help neutralize chime
where is the duodenum found anatomically ?
- to the right of vertebra L1 to L3
- right of the umbilicus
what are the 4 parts of the duodenal ?
- duodenal cap
- descending portion
- horizontal portion
- ascending portion
what are the glands in the duodenal called ?
- glands of Brunner
- secret mucus
what are the jejunum and ileum surrounded by ?
greater sac of peritoneal cavity
covered anterioly by greater omentum
where does the jejunum begin ?
at duodenojejunal flexure
describe the plicae circulares in the ileum :
small in its superior part
absent in terminal part
what are Peyer patches ?
aggregated lymph follicles in mucous membrane
describe the jejunal arteries :
- long vasa recta
- simple arterial arcades
describe the ilea arteries :
short vasa recta
complex arterial arcades
what does the foregut drain into ?
celiac nodes
what does the hindgut drain into ?
inferior mesenteric nodes
what are the pre-aortic nodes ?
- coeliac nodes
- superior mesenteric
- inferior mesenteric
what do the pre-aortic nodes drain into ?
cisterna chyli
what is the mesentery of the appendix ?
mesoappendix
what is reabsorption ?
the large intestines removing fluid + electrolytes within chime
what does the colon do ?
first half absorbs fluids
second half makes waste into fece
what are some functions of the large intestine ?
- absorb h2o and electrolytes
- digest bacteria + viruses
- make faeces
what is the taenia coli ?
longitudinal bands of muscle which cause colon to become circulated
what are haustrations ?
circulations of the colon
what is epiploicae ?
numerous fatty tags on surface of colon
what are the 2 types of churning that occur in the muscle ?
- oestro churning / minor peristaltic wave
- mass peristalsis
how is oestro churning made ?
by segmentation contractions
what initiates mass peristalsis ?
gastrocoloic reflex
what is diverticuli ?
outpouching of the gut
can become filled with fecal matter + become inflammed
what is the ileocecal junction ?
junction that projects into the cecum - acts like a sphincter
prevents reflux into the ileum
what is appendicitis ?
inflammation of the appendix
what are symptoms of appendicitis ?
- muscular rigidity
- pain in right lower quadrant
- vomiting
what is Mc Burneys point ?
how is it found ?
base of the appendix
place little finger in the umbilicus + thumb on anterior superior ileal spine
what supplies the midgut ?
- superior mesenteric artery
- arises from descending aorta
list the branches of the superior mesenteric artery :
- 1st = inferior pancreaticoduodenal artery
- 2nd = jejunal + ileal branches
- 3rd = ileocolic artery
- 4th = right colic artery
- 5th = middle colic artery
where does the pancreaticoduodenal artery supply ?
pancreas + duodenum
where does the ileocolic artery supply ?
- cecal branches
- appendicular artery
what does the right colic artery supply ?
ascending colon
what does the middle colic artery supply ?
transverese colon
what artery supplies the hind gut ?
- inferior mesenteric artery
list the branches of the inferior mesenteric artery :
- left colic artery
- sigmoid arteries
- superior rectal artery
what does the left colic artery supply ?
transverse colon + descending colon
what is the marginal artery of Drummond
anatomoses of all the superior + inferior mesenteric arterys
