digestive tract part 2 Flashcards
what makes up the proximal 2/5 of the small intestine?
jejunum
what makes up the distal 3/5 of the small intestine?
ileum
which segment is most involved in nutrient absorption?
jejunum
which segment absorbs fat soluble vitamins, B12 and bile salts?
ileum
what was an old weight loss procedure that resulted in explosive diarrhea?
jejunoileal bypass
what are the straight terminal branches of the arteries which travel through the mesentery to supply the small intestine?
vasa recta
what are the circular folds found within the small intestine
plicae circulares- increase surface area, slow passage of material
what are aggregations of lymphoid tissue found within the walls of the small intestine?
peyer’s patches- immune defense
what is the blood supply to the ileum and jejunum?
superior mesenteric artery
what is the innervation of the jejunum and ileum?
autonomic fibers from the superior mesenteric plexus
what is a common malformation of digestive tract with a remnant portion of embryonic vitelline duct?
ileal (meckel’s) diverticulum- fingerlike pouch which projects from the distal ileum
diverticulum gets inflamed mimicking appendicitis
what is an autoimmune inflammatory bowel disease which usually affects the distal ileum and adjacent colon?
crohn’s disease
crohn’s disease results in thickening and ulceration of affected segment and has what symptoms?
pain, diarrhea, malabsorption
what is the length of the large intestine?
extends from ileocecal junction of anus and is 1.5 m in length
what is the LI primary function?
convert liquid contents of ileum into semisolid feces by absorbing water
also involved in synthesis of some vitamins- K
what prevents back flow of feces into ileum?
ileal fold
what are the 4 parts of the LI?
cecum -ileal fold appendix colon rectum and anal canal
what attaches the appendix to the mesentery of the ileum?
mesoappendix
what is the most common position of the appendix?
retrocecal
what is the most common intra-abdominal inflammatory condition which involves inflammation of the reniform appendix?
appendicitis
what is the cause of appendicitis?
obstruction of lumen due to:
fecal impaction
lymphoid hyperplasia
what are 3 narrow longitudinal bands of muscle seen most prominently in the cecum and ascending colon?
taeniae coli
what are sacculations of outpouchings of the colon?
haustra of colon
what are small masses of fat which are covered with visceral peritoneum and which extend from colon?
omental appendices
what are herniations of the mucosa of the colon through the muscular layer without inflammation
diverticulosis
where and at what age are diverticulosis most common?
over age 40 and the sigmoid colon
related to low fiber diet
if the diverticuli become inflamed the condition is called?
diverticulitis
how may diverticulosis be treated?
laser endoscopy
what is an auto immune condition that results in sever inflammation and ulceration of the rectum and lower colon that is usually restricted to the mucosa?
ulcerative colitis
what are symptoms of ulcerative colitis?
abdominal pain and diarrhea, bowel perforation may occur
what is a key characteristic of ulcerative colitis?
tear drop deformity
what is the blood supply to the small and large intestine?
superior mesenteric artery- large distribution
inferior mesenteric artery
marginal artery
what are the branches of the superior mesenteric artery?
Inferior pancreaticoduodenal artery jejunal and ileal arteries- 12-15 branches ileocolic artery right colic artery middle colic artery
what provides collateral circulation to colon and prevents a bowel infarction? also endpoint of ischemic bowel disease
marginal artery
what is the mortality rate of transmural bowel infarction?
95%
what are the branches of the inferior mesenteric artery?
left colic- descending colon
sigmoid arteries- sigmoid colon
superior rectal- terminal branch
where do all branches of superior and inferior mesenteric arteries empty into?
marginal artery
what is the straight terminal branch from marginal artery to LI?
vasa recta
what is associated with increased risk of hiatal hernia, inguinal hernia, diverticulosis and colon cancer?
chronic constipation
