GI Organs Flashcards
What are the 10 GI organs?
- esophagus
- stomach
- SI
- colon
- rectum
- anal canal
- spleen
- pancreas
- liver
- gall bladder
What are the abdominal planes? What level is each at?
- transpyloric plane L1
- subcostal plane L2-L3
- transtubercular plane L5
- interspinous plane S2
What level is the esophageal hiatus?
T10
Where does the esophagus enter the stomach?
cardiac orifice at level of T11
What separates the esophagus from fundus of stomach?
cardiac notch
Is the inferior esophageal sphincter anatomical or physiologic?
physiologic
Where are the esophageal constrictions?
- superiorly: level of Cricoid cartilage, juncture with pharynx
- middle: crossed by aorta and left main bronchus
- inferiorly: diaphragmatic sphincter
Describe a para-esophageal hiatal hernia
- cardia of stomach in normal position
2. peritoneum and fundus of stomach are anterior to esophagus
Describe a sliding hiatal hernia
esophagus, cardia of stomach, and fundus of stomach protrude through esophageal hiatus
What is the volume and location of the stomach?
volume 2-4 liters
location - right and left upper quadrants
- left end fixed at level T10-11
- right end fixed at level T11
What are the parts of the stomach?
cardia, fundus, body, and pylorus
What is the greater curvature of the stomach?
inferior border; greater omentum attaches here
What is the lesser curvature of the stomach?
superior border; lesser omentum attaches herre
What is a truncal vagotomy?
denervates nerve supply to all of stomach plus most of GI tract and liver
What is a proximal gastric vagotomy?
denervates branches of vagus nerve going only to the stomach
What is a selective proximal vagotomy?
specifically denervate area of stomach in which parietal cells are located
What is in the anterior abdomen?
abdominal wall, left costal margin, diaphragm, left lobe of liver
What is in the posterior abdomen?
lesser sac, pancreas, transverse mesocolon, transverse colon, left kidney/suprarenal gland, spleen/splenic artery
What is in the superior abdomen?
left dome of diaphragm
Where does the duodenum begin and end?
begins at pylorus and ends at duodenojejunal junction
What level is the duodenojejunal junction?
L2
What is the length of the duodenum?
10”
How many parts are in the duodenum?
4
Describe the 1st part of the duodenum
intraperitoneal
1” long
travels superior and right
associated with the hepatoduodenal ligament
What is anterior, posterior, lateral, and medial to the 2nd part of the duodenum?
anterior
- gallbladder fundus
- right lobe of liver
- transverse colon
- coiled of SI
posterior
- hilum of right kidney
- right ureter
lateral
- right colic flexure
- ascending colon
- right lobe of the liver
medial
- head of the pancreas
- bile and pancreatic ducts
What is anterior, posterior, superior, and inferior to the 3rd part of the duodenum?
anterior
- root of the mesentery of SI
- superior mesenteric vessels contained within the mesentry
- coils of jejunum
posterior
- right ureter
- right psoas muscle
- inferior vena cava
- aorta
superior
- head of pancreas
inferior
- coils of jejunum
What is posterior, right side, left side, and superior to the 4th part of the duodenum?
posterior
- left crus of diaphragm
- left psoas major muscle
- left sympathetic trunk
- left renal vessels
- left gonadal vessels
- left supra renal vein
- inferior mesenteric vein
right side
- uncinate process of pancreas
left side
- left kidney and ureter
superior
- body of pancreas
How long is the 4th part of the duodenum?
2.5 cm
What is the location of the jejunum?
LUQ
intraperitoneal supported by mesentery
What is the jejunum?
proximal 2/5 of SI
- contains mucosal folds (plicae circulares)
- mesenteric fat increases from proximal to distal
- supplied by arterial arcades with long vasa recta (straight arteries)
Where is the ileum?
RLQ
intraperitoneal supported by mesentery
What is the ileum?
distal 3/5 of SI
-supplied by compound arterial arcades with short vasa recta (straight arteries)
What is the mesentery?
- attaches jejunum and ileum to posterior body wall
- 2 layers of peritoneum
What does the mesentery contain?
superior mesenteric a/v, lymph nodes, fat, and autonomic nerves
Where is the mesentery?
crosses 3rd/4th parts of duodenum, aorta, IVC, right ureter, right psoas major, and right gonadal a/v
What is Ileal (Meckel’s) Diverticulum?
- congenital anomaly occurs in 1-2% of population.
- located 50 cm from ileocecal junction in adults
- may be free (74%) or attached to umbilicus (26%)
- may become inflamed and mimick pain produced by acute appendicitis
What are the parts of the colon?
cecum, appendix, ascending colon, transverse colon, descending colon, and sigmoid colon
What is the length of the colon?
approx 5’
Where does the colon begin?
ileocecal junction
What are the external features of the colon?
3 tenia coli, haustra and appendices epiploicae (store fat)
What is the cecum?
blind pouch (intraperitoneal) continuous with ileum and ascending colon
What is the appendix attached to and supported by?
attached to posterior-medial part of cecum and supported by mesoappendix
What does the appendix contain?
several lymphoid nodules (immune system)
What are the signs of acute appendicitis?
- ill looking pt, low grade fever
- coughing may cause increased pain (Dunphy’s sign)
- tenderness at McBurney’s point, involuntary guarding
- site of tenderness may vary depending on appendix position
- pain felt in the RLQ during palpation of LLQ (Rovsing’s sign)
What indicates a perforated appendix?
more severe and diffuse abdominal pain, tenderness and abdominal rigidity
Where is McBurney’s Point?
2/3 from the umbilicus in an imaginary line toward the right ASIS
Describe the cecum
- contains ileal papilla (cone-like projection of ileum)
- ileocecal valve regulates passage of ileal contents into cecum
How long is the ascending colon?
8-10”
Describe the ascending colon
- continuous with cecum and transverse colon at right colic (hepatic) flexure
- retroperitoneal organ adjacent to right paracolic gutter
How long is the transverse colon?
10-14”
Describe the transverse colon
- suspended by the transverse mesocolon
- continuous with descending colon at right colic (splenic flexure)
Describe the descending colon
- retroperitoneal - left paracolic gutter lateral to descending colon
- continuous with sigmoid colon
How long is the sigmoid colon?
12”
Describe the sigmoid colon
- continuous with the rectum at level of S3
- suspended by sigmoid mesocolon
What is volvulus of sigmoid colon?
- rotation and twisting of the mobile loop of the sigmoid colon and sigmoid mesocolon
- results in obstruction of the lumen of the descending colon and any part of sigmoid colon proximal to the twisted segment
- obstipation and ischemia of the looped portion of sigmoid colon may result
- ACUTE SURGICAL EMERGENCY
What is the length of the rectum?
5”
Describe the rectum
- both retroperitoneal and subperitoneal
- located in pelvic cavity
- contains 3 transverse rectal folds (superior, middle, inferior)
- continuous with anal canal
What is the length of the anal canal?
1 1/2”
Describe the anal canal
- surrounded by 2 anal sphincters: internal anal sphincter comprised of smooth muscle and external anal sphincter comprised of skeletal muscle
- contains anal columns, anal valves, and anal sinuses
- pectinate line located at inferior ends of anal valves
- external opening known as the anus
Where is the spleen located?
LUQ or left hypochondriac region lying parallel to left ribs 9-11 along the mid-axillary line between the stomach and diaphragm
Describe the spleen
intraperitoneal organ attached to both the gastrosplenic and splenorenal ligaments
What is superior, anterior, posterior, and inferior to the spleen?
superior (diaphragmatic surface)
-diaphragm
(visceral surface)
anterior
-fundus of stomach
posterior
-left suprarenal gland and kidney
inferior
-tail of pancreas and left colic flexure
Where is the pancreas located?
Describe the parts of the pancreas and their locations
at level of L1-L2
head - in curvature of duodenum
neck - indistinct; joins head to body; overlies superior mesenteric A
body
tail - located within the splenorenal ligament; tip is adjacent to hilum of spleen
uncinate process - adjacent to head; superior to duodenum
What are the ducts of the pancreas?
main pancreatic duct - begins in tail and courses to the head. Joined by accessory duct in head. Contains sphincter of the main pancreatic duct, which prevents bile entering the pancreas. Joins common bile duct.
accessory pancreatic duct - may have a separate opening in the duodenum at the minor duodenal papilla
What is the hepatopancreatic ampulla?
- formed by union of common bile duct and main pancreatic duct
- associated with sphincter of Oddi and major duodenal papilla
What is anterior, posterior, to the right and left, and inferior to the pancreas?
anterior
- lesser sac (omental bursa)
- stomach
posterior
- aorta
- IVC
- splenic V
- common bile duct
- right crus of diaphragm
- left kidney and vessels
- left suprarenal gland
- superior mesenteric A/V
right
-2nd part of duodenum
left
-spleen
inferior
-3rd part of duodenum
What is the size of the liver?
5% body weight in infants
2% body weight in adults
What is the location of the liver?
RUQ or epigastric and right hypochondriac regions; left lobe in LUQ
What are the surfaces of the liver?
diaphragmatic surface - concavity of diaphragm; covered in peritoneum except where in direct contact with diaphragm; IVC in direct contact
visceral surface - convered with peritoneum except where gall bladder and porta hepatis are located; transmits portal hepatis
What is porta helpatis?
transverse fissure on visceral surface; contains hepatic portal v, hepatic artery proper, nerve plexus, hepatic bile ducts, and lymphatic vessels
What is the left sagittal fissure and right sagittal fissure of the liver?
both - on visceral surface
left - contains ligamentum teres (obliterated umbilical v)
right - contains gall bladder and IVC
What are the lobes of the liver?
right - larger than left; includes quadrate and caudate lobes, which are separated by porta hepatis
left - smaller than right; separated from right by falciform ligament
caudate - between IVC and falciform ligament
quadrate - between gall bladder and falciform ligament
What are functional liver lobes based on?
How many segments?
- based on division of the portal triad and blood supply
- right and left liver divided by Cantlie line
- 8 segments
What is the coronary ligament?
reflection of visceral peritoneum from liver to the respiratory diaphragm; surrounds bare area of liver
What are the 2 parts of the lesser omentum?
1 hepatogastric ligament - passes from porta hepatis to lesser curvature of stomach
- hepatoduodenal ligament - passes from porta hepatis to duodenum (1st part); contains proper hepatic A, hepatic portal V, common bile duct, lymphatic vessels, and hepatic nerves
What is alcoholic cirrhosis of the liver?
- most common type characterized by hepatomegaly and “hobnail” appearance of the liver surface, resulting from fatty changes and fibrosis
- genetic component in males related to amount of hair on chest
What is cholelithiasis?
Gall Stones
- made of cholesterol crystals
- can be lodged in several structures such as cystic duct, hepatic duct, or hepatopancreatic ampulla
- blockage of hepatopancreatic ampulla blocks both common bile duct and main pancreatic duct; results in bile backing up into pancreas –> pancreatitis
What are common risk factors for Gall Stones and Gall Bladder Disease?
- female: male 2:1
- obese
- Forty’s - risk increases with age
- fertile (pre-menopausal)
- pregnancy
- ethnicity - American Indians and Mexican Americans at highest risk
- Diabetes
- Estrogen replacement therapy
What causes obstructive jaundice?
-stones inside the common bile duct and billiary tree
