Organs of the GI Tract Flashcards
Thoracic esophagus
pierces the diaphragm at T 10
turns to the left and enters the stomach at the cardiac orifice at T 11
sliding hiatal hernia
esophageal hiatus of diaphragm enlarges or weakens
abdominal esophagus and parts of the stomach heriate into the thorax
paraesophageal hiatal hernia
a defect in diaphragm next to the esophageal hiatus
permits fundus of stomach to herniate
stomach
left end - fixed at T10-11
right end - fixed at L1-2
Duodenum
C shaped
10 inches long
Located at L1-4
1st part of duodenum - superior
starts at pyloric sphincter
rugae
2 inches long
held in place by hepatoduodenal ligament
posterior - portal vein, hepatic artery, bile duct
inferior - pancreas
2nd part of duodenum - descending
3 inches long
vili and pailla (biliary and pancreatic ducts empty)
all retroperitoneal
anterior - gall bladder, R lobe of liver, transverse colon
posterior - R kidney and ureter
medial - head of pancreas
bile and pancreatic ducts enter into he second part of the duodenum at the major duodenal papilla
3rd part of duodenum - horizontal
villi
superior mesenteric artery and vein and the root of the mesentery cross the anterior surface
superior - head of pancreas
anterior and inferior - jejunum
4th part of duodenum - ascending
becomes intraperitoneal
anterior - root of mesentery and jejunum
posterior - left margin of the aorta and medial border of psoas muscle
held in place by the suspensory ligament which anchors the 4th part of the duodenum to the R crus of the diaphragm
Jejunum and Ileum
20 feet long
jejunum - starts at duodenal-jejunal junction and ileum ends at the ileo-cecal valve
very mobile and help to posterior wall by THE mesentery
framed by large intestine
Jejunum
8-10 feet long 2/5 of free small intestine simple vascular arcades, long vasa recta, more vascular greater diameter, thicker, more plicae circularis
Ileum
10-12 feet long 3/5 of free small intestine compound vascular arcades, shorter vasa recta, is less vascular smaller diameter thinner wall fewer plicae circularis
Meckel’s diverticulum
feature of the ileum arises from the antimesenteric border of the ileum occurs in 2% of population 2 feet from the ileocecal junction 2 inches long remnant of the vitelline duct
THE mesentery
15 cm long at the root attaches the jejunum & ileum to the posterior body wall crosses L 1-2 3rd part of duodenum aorta IVC R ureter R gonadal vessels R psoas major ends at right SI joint
large intestine
highly mobile function - fecal formation, transport , and evacuation, water absorption and mucus secretion
Taenia coli
3 bands of longitudinal m on outside of the colon
converge at the root of the appendix
produce haustrae that slow the movement of feces
Appendices epiploicae
tags of fat
characteristic of the large intestine
cecum
no epiploic appendages
blind puch inferior to ileocecal orifice
iliocolic valve is 2 folds that are not a true sphincter
ileal papilla is a cone-like projection of the ileum into the cecum
the opening for the appendix is inferior to the ilial papilla
vermiform appendix
attached to the postero medial part o the cecum
located at the unction of the 3 taenia coli
9-10 cm long and supported by a mesoappendix
position variable
ascending colon
R iliac fossa to R flexure
ant. to R kidney
secondarily retroperitoneal except lowest part
transverse colon
R colic flexure to L colic flexure
intraperitoneal
phrenicocolic ligament - L flexure to diaphragm
Transverse mesocolon - pancreas to greater omentum
descending colon
L flexure to pelvic brim
secondarily retroperitoneal
sigmoid colon
sigmoid mesocolon
rectosigmoid junction - ant. to S3
intraperitoenal
rectum
b/w sigmoid colon and anal canal
contains rectal ampulla (dialated terminal part of rectum)
anorectal line - a line joining the tops of the anal columns
3 transverse rectal folds - superior, intermediate, inferior
puborectalis m - relaxation leads to defecation
