Large Intestine Basics Flashcards
Large intestine location
Caecum to anal canal
Cell type in large intestine
Columnar epithelium
Role of LI
Removes water from indigestible gut contents, turns chyme into semi solid
Production of vitamins
Temporary storage until defacation
environment of LI
Micro biome- contains lots of commensal bacteria
Colonic mucosa gets majority of nutrients from where
Not from blood
Short chain fatty acids derived from the fermentation of dietary fibre
By-products include CO2, Methane and H+ gas
Ascending and descending colon position
Retroperitoneal
Transverse colon has its own
Mesentary (transverse mesocolon)
Sigmoid colon has its own
Mesentary
Positioning of rectum
Upper 1/3 intra-peritoneal
Middle 1/3 retroperitoneal
Lower 1/3 no peritoneum
Arterial supply to LI midgut component
Midgut component- superior mesenteric artery
Ilio-colic = caecum
Right colic = ascending colon
Middle colic = transverse colon
Arterial supply to LI hindgut component
inferior mesenteric artery
left colic - descending colon
Sigmoid- descending colon
Superior rectal artery- upper 1/3 rectum
venous drainage of LI (midgut and hindgut)
Midgut drains into superior mesenteric vein
Hindgut drains into inferior mesenteric vein
venous drainage of LI rectum
Upper 1/3 drains into superior rectal vein
Middle and lower 1/3ds drain into systemic venous system- site of Portosystemic anastomoses
Large intestine and small intestine anatomical differences
LI shorter and wider
LI has crypts not villi
Anatomy of bands of large intestine
External longitudinal muscle is incomplete
3 distinct bands (teniae coli)
Haustra are sacculations caused by contraction of teniae coli
