Intestines

Question 1

small intestines

Answer 1

stomach to caecum
sub-parts: duodenum, jejunum (first 2/5), ileum (last 3/5)

Question 2

differences between jejunum and ileum

Answer 2

ileum usually located in pelvis
ileum has smaller lumen
ileum has shorter and more vessels
both total 6-7m
has mesentery which are folds that attaches intestine to wall of stomach area to hold in place

Question 3

large intestine

Answer 3

distal portion of GI tract
begins and cecum and ends at anal canal
absorbs water and electrolytes from food to form faeces

Question 4

parts of large intestines

Answer 4

ascending- begins at cecum ends at right colic flexure (where intestine turns to face right)

transverse- begins at right colic flexure and ends left colic flexure (where intestine turns to face down)

descending- begins left colic flexure ends at sigmoid (where turns right to face medially)

sigmoid- starts at end of descending and ends at rectum

Question 5

features of large intestine

Answer 5

larger lumen than small inestine
taeniae coli- external, longitudinal muscle layer of large intestine
appendices epiploicae- small hanging projections filled with fats on intestinal wall
haustrations- pouches along the colon produces from tightening of taeniae coli

Question 6

intraperitoneal vs retroperitoneal

Question 7

mesentery of large intestines (mesocolon)

Answer 7

attaches large intestine to posterior abdominal wall
ascending colon- attaches directly to pos abdo wall, retroperitoneal, cecum no mesentery
transverse colon- attaches indirectly to pos abdo wall via bare area, intraperitoneal
descending- attaches directly to pos abdo wall, retroperitoneal
sigmoid colon- attached indirectly as sigmoid colon is attached to sigmoid mesocolon which is attached to pos pelvic wall, intraperitoneal

Question 8

abdominal viscera

Answer 8

water absorption, stool formation and temp storage

Question 9

blood supply to gut

Answer 9

3 vertebral branches of descending abdominal aorta:
coeliac trunk- fore-gut
superior mesenteric artery- mid-gut
inferior mesenteric artery- hind-gut

Question 10

superior mesenteric artery (SMA)

Answer 10

branches: pancreaticoduodenal, jejunal, ileal, ileocolic (caecum, ascending colon), right colon (ascending colon, right colic flexure), middle colic (ascending, transverse, right colic fixure)

branches from SMA attaches to IMA to form marginal artery

SMA supplies: jejunum, ileum, caecum, appendix, ascending, transverse colon

Question 11

inferior mesenteric artery (IMA)

Answer 11

branches: left colic (supplies descending), sigmoid artery (supplies sigmoid colon), superior rectal (supplies rectum)

Question 12

superior and inferior mesenteric veins

Answer 12

IMV leads into splenic vein which combines with SMV to form portal vein which leads to liver then hepatic veins then IVC

Question 13

caecum

Answer 13

first part of large intestine, leads to ascending colon
no mesentery
vessels: iliecolic artery (SMA), ileocolic vein (SMV)
nerves: vagus nerve, superior mesenteric ganglion and plexus
lymphatic: iliecolic nodes that drain into mesenteric nodes