Midgut and Hindgut Flashcards
Describe midgut generally
Starts in 2nd portion duo
Part of gi tract forming ost of intestines
What supplies midgut
Superior mesenteric a = 2nd unpaired branch aorta
Describe content midgut
Duo - distal 1/2
Jejunum
Ileum
Cecum and appendix
Ascending colon
Transverse colon - prox 2/3
Describe hind gut Gen
Distal portion gi
Shortest portion
What supplies hindgut
Inferior mesenteric a
Describe contents hindgut
Transverse colon = distal 1/3
Descending colon
Sigmoid colon
Recto
Anal canal (upper part)
Describe transition to midgut
In 2nd portion duo = blood supply changes
Describe transition from duo to jejunum
Duodenal flexure
Si = intra
Describe arterial supply duodenum - anastomoses
Superior pancreaticoduodenal (gastroduodenal - common hepatic - celiac trunk) and inferior pancreaticoduodenal (sma) arteries anatomose
Describe jejunum
2nd portion si
Makes proximal 2/5 si
Specialized in nutrient absorption
What is location of jejunum
From duo at duodenojejunal flexure
(Made by suspensory muscle/lig of duo = treitz)
To ileum
Is there a clear anatomical distinction between duo and jejunum
No
What is treitz
Extension so do not regurgitate in mouth, Smooth muscle fibers to help contract
What is purpose of suspensory ligament of jejunum
Jejunum heavy
When Breathe in = increased pressure produced by diaphragm, contract les and pull on treitz = reduce this increased pressure
What is found in jejunum - folds
Plicae circulares = numerous circular folds in its lumen
Increased surface area for absorption
Rugged wall, 1st portion received a much richer bolus
Describe arterial supply distribution jejunum
Less prominent arterial arcades
Long vasa recta (straight arteries)
Compare jejunum and ileum - muscle
Ileum = Less plicae, more smooth, peyers patches
Describe ileum
Final section si
Makes distal 3/5 of si
Longer than jejunum
Describe location of ileum
From jejunum (suspended in mesentery) to ileocecal junction - forms sphincter like end
Describe anatomical distinction of ileum
Contains lymphoid nodules = peyers patches
Plicae circulares = low and sparse
Denser arterial arcades and shorter vasa recta
Compare arterial supplies of jejunum and ileum
Jejnum = long vasa recta, proximal
Ileum = short vasa recta, many of arterial arcades, distal, I LOVE ARCADE FIRE
Describe mesentery of si
Ileum and Jejunum suspended in mesentery = peritoneal fold that carries blood vessels, lymphatics and nerve fibers
Link post abd wall to organ
Describe arterial supply midgut - Gen
From sma
Gives jejunal and ileal arteries
Ends in arterial arcades and vasa recta
What is root of mesentery
Entry/exit vasculature
Describe large intestine
1.5m long and large diameter
Extends from cecum to anal canal
Converters liquid feces to semi solid state
Absorbs water, salt and electrolytes
Describe parts of li
Cecum, appendix, colon (ascending, transverse, descending, sigmoid), rectum, anal canal
Transition to hind gut = in transverse colon