Small Intestine Flashcards
What is the longest part of the GI tract?
small intestine
What does the small intestine extend from?
pyloric orfice to ileocecal junction
How long is the small intestine?
7 m in length
What does the small intestine absorb?
nutrients and water
What does the large intestine absorb?
some water
Where does almost entirely all the absorption occur?
small intestine
What three parts make up the small intestine?
duodenum (shortest)
Jejunum (longest)
Ileum (distal part)
What is the duodenum?
C-shaped tube surrounds the head of the pancreas
What is the characteristics of duodenum in length and width?
25 cm long and widest part of small intestine
What are the four parts of the duodenum?
superior part
descending part
inferior part
ascending par
Where is the duodenal cap (ampulla)?
beginning of superior part
What is in the descending part?
junction for foregut and midgut where bile and pancreatic duct empty
What is the longest part of the duodenum?
inferior part
What are duodenal brunner glands?
secrete an alkaline mucus which gives dilute stomach acid
Suspensory muscle is what?
fibromuscular band which extends from diaphragm to duodenojejunal flexure
What is the only part of the duodenum that isnt retroperitoneal?
duodenal cap (distal end of 4th part might also be intraperitoneal)
Where does the mesenteric artery and vein pass?
anterior to third part of duodenum
What is the blood supply to the duodenum?
superior and inferior pancreaticoduodenal artery
supraduodenal artery
What does the inferior pancreaticoduodenal artery supply?
third and fourth part of duodenum
What is the innervation of the duodenum?
autonomic fibers from the celiac and superior mesenteric plexuses
What part does the jejunum make up of the small intestine?
proximal 2/5, distal to duodenum
Where does the jejunum begin?
duodenojejunal flexure
What part does the ileum make up of the small intestine?
distal 3/5
What segment of GI tract is most involved in nutrient absorption?
jejunum
What does the ileum absorb?
fat soluble vitamins, b12, bile salts
What suspends the jejunum and ileum from the posterior abdominal wall?
mesentery which carries blood vessels, nerves and lymphatics
What do peyer’s patches produce?
lymphocytes to defend GI
What is the plicae ciruclares for?
increase surface area
slow passage of material
What is the vasa recta?
straight terminal branches of the arteries which travel through the mesentery to supply the small intestine
Does the jejunum have mesenteric windows?
yes
Does the ileum have mesenteric windows?
no because to much fat
What color is jejunum?
dark red
What color is ileum?
pale pink
Does jejunum or ileum have better vascularity?
jejunum
Which one is bigger in diameter? jejunum or ileum?
jejunum
Which walls are thicker? jejunum or ileum?
jejunum
Whose vasa recta is longer? jejunum or ileum?
jejunum
Which one has less mesenteric fat? jejunum or ileum?
jejunum
Which one has more plicae cirulares? jejunum or ileum?
jejunum
Which one has peyer’s patches? jejunum or ileum?
ileum
What is the blood supply to the jejunum and ileum?
jejunal and ileal branches of superior mesenteric artery
What is the innervation of the jejunum and ileum?
autonomic fibers from superior mesenteric plexus
