GI Organs Flashcards
where does the thoracic esophagus pierce the diaphragm?
T10
where does the esophagus enter the stomach at the cardiac orifice?
T11
where does the aorta pass thru the diaphragm?
T12
where does the inferior vena cava pass thru the diaphragm?
T8
sliding hiatal hernia
-esophageal hiatus of diaphragm enlarges or weakens
abdominal esophagus and parts of the stomach (cardia and sometimes fundus) herniate into the thorax
paraesophageal hiatal hernia
i. A defect in diaphragm next to the esophageal hiatus
ii. Permits fundus of stomach to herniate (not usually the esophagus)
1. These occur next to the esophagus, so defect of diaphragm next to the esophagus
2. Fundus comes up next to esophagus
where is stomach fixed?
i. Left end fixed at T10-11 at esophagus
ii. Right end fixed at L1-2 at duodenum
iii. Area b/w is variable—b/c stomach can get larger or smaller
duodenum
- C shaped
- 10 inches long
- located approximately at L1 to L4 vertebral bodies
- starts at the pylorus of the stomach and ends at the duodenal jejunal junction
- further subdivided into 4 parts:
a. superior
b. descending
c. horizontal
d. ascending - secondarily retroperitoneal
superior duodenum
i. starts at pyloric sphincter
ii. about 2 inches long
iii. held in place by the hepatoduodenal ligament
iv. portal V, hepatic A, and bile duct are therefore posterior and superior to this part
v. duodenal bulb—widened area
vi. head of the pancreas is inferior to this part
descending duodenum
i. about 3 inches long
ii. all secondarily retroperitoneal
iii. fundus of the gall bladder, right lobe of the liver, transverse colon are all anterior
iv. R kidney and ureter are posterior
v. Head of the pancreas is medial
vi. Bile and pancreatic ducts enter into the second part of the duodenum at the major duodenal papilla
horizontal duodenum
i. Superior mesenteric A and V and the root of the mesentery cross the anterior surface of the 3rd part of the duodenum
ii. Head of the pancreas is superior
iii. Jejunum is anterior and inferior
ascending diaphragm
i. Becomes intraperitoneal—not covered by parietal peritoneum
ii. Root of the mesentery and jejunum are anterior
iii. Left margin of the aorta and the medial border of the psoas muscle are posterior
iv. 4th part is held in place of the suspensory ligament (or muscle) of the duodenum (of Treitz)
1. suspensory ligament anchors the 4th part of the duodenum to the right crus of a diaphragm
jejunum
a. 8-10 feet
b. 2/5 of free small intestine
c. simple vascular arcades, long vasa recta, more vascular
d. greater diameter, thicker, more plicae circularis
plicae circularis
circular folds that go around jejunum
ileum
a. 10-12 feet long
b. 3/5 of the free small intestine
c. has compound vascular arcades, shorter vasa recta, is less vascular
d. is smaller diameter, thinner wall
e. fewer plicae circularis
meckel’s diverticulum
i. Most common congenital anomaly of the small intestine
ii. Arises from the antimesenteric border of the ileum
iii. Occurs in about 2% of the population
iv. About 2 feet from the ileocecal junction
v. Average about 2 inches long
vi. Remnant of the vitelline duct
vii. Clinically difficult to distinguish from appendicitis
viii. May contain other types of tissues
**usually 2 inches long, occurs 2 feet from ileocecal valve, in about 2% of the population, usually occurs in first 2 years of life, 2 types of epithelia–gastro and intestinal
taenia coli
a. 3 bands of longitudinal muscle on the outside of the colon
i. converge at the root of the appendix
ii. produce houstrae that slow movement of feces
epiploic appendages
i. tags of fat
ii. characteristic of large intestine
cecum
i. no epiploic appendages
ii. blind “pouch” inferior to ileocecal orifice
iii. iliocolic valve is 2 folds that are not a true spincter
iv. ileal papilla is a cone like projection of the ileum into the cecum
v. opening for the appendix is inferior to the ileal papilla
vermiform appendix
i. usually attached to the posteromedial part of the cecum
ii. located at the junction of 3 taenia coli
iii. 9-10 cm long and supported by a mesoappendix
iv. position is variable
ascending colon
- R colic feature—hepatic flexure
- Secondarily retroperitoneal
a. Except lowest part
transverse colon
- Left colic flexure (splenic flexure)
2. Intraperitoneal—transverse mesocolon
descending colon
- Secondarily retroperitoneal
sigmoid colon
- intraperitoneal
rectum
i. b/w sigmoid colon and anal canal
ii. anorectal line—line joining the tops of the anal columns
iii. b/w the sigmoid colon and the anal canal
iv. transverse rectal folds—superior/intermediate/inferior
v. rectal ampula—dilated terminal part of the rectum
vi. puborectalis muscle—defacation and relaxation of internal and external anal sphincters
pectinate line above and below
- above—simple columnar, superior rectal A, inferior hypogastric plexus
- below—stratified squamous, middle and inferior rectal A, inferior rectal N
parts of anal canal
i. Anal valves—at the base of the anal columns
ii. anal sinuses—spaces b/w and at the inferior part of the anal columns
iii. pectinate line—line joining the inferior end of the anal valves
spleen–size, shape, location
i. left hypogastric region
ii. parallels left ribs 9-11
iii. midaxillary line, b/w stomach and diaphragm
iv. about size of hand
v. normally not palpable below costal margin
relations of spleen
i. diaphragm is posterior
ii. stomach, left colic flexure, and tail of pancreas are anterior
iii. the left kidney and phrenicocollic ligament are inferior
peritoneal relationships of spleen
i. covered by peritoneum
ii. develops from dorsal mesentery from mesoderm
1. gastrosplenic ligament
2. splenorenal ligament
surfaces of the spleen
i. diaphragmatic
1. against diaphragm
2. smooth
ii. visceral
1. hilum with gastrosplenic and splenorenal ligaments
2. there are colic, gastric, and renal impressions here
pancreas location and peritoneal
a. mostly secondarily retroperitoneal
b. located at L1-2
parts of the pancreas
i. head
1. with uncinate process
2. in the duodenal curve
ii. body
1. triangular cross section
iii. neck
1. constricted part b/w head and body
iv. tail
1. some of tail is located in the splenorenal ligament
2. anterior to the hilus of the spleen
relationships of the pancreas
i. superior mesenteric A and V are posterior to the neck
ii. splenic V and A run horizontally superior to or posterior to the body
iii. tail is against the spleen
iv. IVC and aorta are posterior to the body
v. Stomach is anterior to the spleen
vi. Duodenum is superior, right and inferior to the head
vii. Transverse colon lies anterior and inferior to the pancreas
pancreatic duct system
i. Pancreas develops from a ventral bun in the ventral mesentery and a larger dorsal bud in the dorsal mesentery
1. Rotation of the stomach and the duodenum brings these buds together and the duct systems unite
ii. The main or major pancreatic duct joins the bile duct and they enter the 2nd part of the duodenum together thru a common hepatopancreatic ampulla
1. This forms the major duodenal papilla
iii. The accessory pancreatic duct enters the duodenum at the more superior minor duodenal papilla
liver location and lobes
a. Most of the liver is in the RUQ
b. Smaller left lobe in the LUQ
4 lobes of the liver
i. left lobe
ii. right love
iii. caudate lobe
iv. quadrate lobe
falciform ligament of the liver
a. the falciform ligament is a double layer of peritoneum that connects liver to the anterior wall
i. remnant of the obliterated umbilical vein
liver surfaces and ligaments
i. diaphragmatic surface
1. smooth, fits concavity of diaphragm
2. peritoneum attaches the liver to the anterior body wall and the peritoneum splits to enclose a bare area
a. bare area—anterior, posterior, left and right coronary ligament define this area
i. includes the area where the IVC is posterior to the liver and the hepatic veins drain into it
liver peritoneal attachments
i. falciform ligament with ligamentum teres
ii. lesser omentum with hepatoduodenal and hepatogastric ligaments
location of gall bladder
in hepatic fossa
fundus of gall bladder
i. lowest, widest part
ii. contacts anterior abdominal wall at the midclavicular line, 9th or 10th costal cartilage
iii. usually located on the transpyloric line
extra hepatic bile passages of the gall bladder
i. together the R hepatic duct and L hepatic duct form the common hepatic duct
ii. cystic duct
iii. bile duct
common bile duct
- formed from the cystic and the common hepatic ducts
- runs in the edge of the lesser omentum (hepatoduodenal ligament)
- goes posterior and inferior to the 1st part of the duodenum, posterior to the head of the pancreas, enters the 2nd part of the duodenum with the pancreatic duct
length of jejunum vs. ileum
8-10 ft vs. 10-12 ft
arcades and vasa recta of jejunum vs. ileum
- simple and long
- complex and short
overall blood supply of jejunum vs. ileum
- more vascular in jejunum
- less vascular in ileum
plicae circularis of the jejunum vs. ileum
- more plicae circularis in jejunum
- less plicae circularis in ileum
diameter of ileum vs. jejunum
- greater diameter in jejunum
- smaller diameter in ileum
lymph above the pectinate line vs. below
- internal iliac LN above
- superficial inguinal LN below
epithelium above vs. below the pectinate line
- simple columnar above
- stratified squamous below
embryo of above vs. below pectinate line
- endoderm above
- ectoderm below
artery supply above vs. below pectinate late
- superior rectal A. above
- middle and inferior rectal A. below
veins above the pectinate line vs. below
- superior rectal V above
- middle and inferior rectal V below
hemorrhoids above vs. below pectinate line
- internal above
- not painful–visceral
- external below
- painful–somatic
nerves above pectinate line vs. below
- inferior hypogastric plexus above
- inferior rectal N below
