Lecture 5: Organs of the GI tract Flashcards
The esophagus enters the abdomen at which costal cartilage and vertebral level; through which opening?
Tip of the left 7th costal cartilage at T10; the esophageal hiatus
The esophagus enters the stomach at which costal cartilage at what spinal level?
Tip of the left 8th costal cartilage at T11
The pylorus of the stomach is in which plane and spinal level?
Transpyloric plane; L1
What are the constrictions of the esophagus?
1) Cervical constriction (upper esophageal sphincter) 2) Thoracic (broncho-aortic) constriction 3) Diaphragmatic constriction (lower esophageal sphincter)
The what forms the cervical constriction and thoracic constriction of the esophagus?
- Cervical (upper) = Cricopharyngeus m.
- Thoracic (broncho-aortic) = left main bronchus
What are the 2 types of Hiatal Hernias?
1) Para-esophageal hernia
2) Sliding hiatal hernia
What are the characteristics of a Para-esophageal hernia?
- Cardia of stomach in normal position, but peritoneum and fundus anterior to esophagus
- No regurgitation
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What are the characteristics of a Sliding Hiatal Hernia?
- Most common
- Esophagus, cardia, and fundus through hiatus
- Especially bad when laying down/bent over
- Regurgitation
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What quadrants does the stomach lie in?
RUQ and LUQ
What are the spinal levels of the stomach?
- Left end fixed at T10-T11
- Right end fixed at L1
Is stomach intraperiotneal or retro-?
Intraperitoneal
What is found anterior to the stomach (relationships)?
- Anterior Abdominal Wall
- Diaphragm
- Left lobe of liver
What is found posterior to the stomach (relationships)?
- Diaphragm
- Spleen (posterior and lateral)
- Left suprarenal gland
- Left upper kidney
- Pancreas
- Transverse colon (inferior and lateral)
- Transverse mesocolon
- Omental bursa
Where does the Duodenum begin and end (strucutres and spinal levels)?
Begins at pylorus (L1), ends at duodenojejunal flexure (L2)
Which parts of the duodenum are intraperitoneal and which are retroperitoneal?
- First part = intraperitoneal
- 2nd-4th parts = retroperitoneal
What is the important ligament in the 1st part of the duodenum; why?
- Hepatoduodenal ligament (lesser omentum)
- Contains the Portal triad
What makes up the portal triad?
1) Portal vein
2) Hepatic artery
3) Bile duct
Whats significant about the second part of the duodenum?
Where the bile duct and pancreatic duct enter, so this is where bile will start to be found within the GI tube
The bile and pancreatic duct meet up and enter the second part of the duodenum through which strucutre, this forms the?
Converge and together through a common hepatopancreatic ampulla and form the major duodenal papilla (of Vater)
Where do the SMA and SMV lie in relation to the pancreas and duodenum?
- Lie posterior to the pancreas and cross the 3rd part of duodeum anteriorly
What is the suspensory ligament of the duodenum (of Treitz)?
Anchors 4th part of duodenum to right crus of the diaphragm
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What quadrant is the Jejunum in, makes up how much of small intestine?
LUQ; 2/5 of the small intestine
What quadrant is the Ileum in, makes up how much of small intestine?
RLQ; 3/5 of small intestine
What are distinguishing features of the Jejunum (arcades, vasa recta, vascularity, wall)?
- Few/lareger arcades
- Long vasa recta
- More vascular
- Thicker and greater diameter
What are distinguishing features of the Ileum (arcades, vasa recta, vascularity, wall)?
- Many/short arcades
- Shorter vasa recta
- Less vascular
- Smaller diameter; thinner walls
How do they Peyer’s patches differ in the Jejunum vs Ileum?
Jejunum = Few Peyer’s patches
Ileum = Many Peyer’s patches
What are the Plicae Circulares like from the proximal jejunum to terminal ileum?
Proximal jejunum = More plicae circulares
Terminal ileum = Very few plicae circulares
What is the ileocolic junction and what spinal levels does it occupy (what type of peritoneal)?
- Where ileum meets the cecum at L5 and goes down to S2 (intraperitoneal)
What are the spinal level boundaries of the ascending colon and where does it stop (type of peritoneal)?
Starts at L5 and moves up to the transpyloric plane at L1, stops at the hepatic flexure (left colic).
* Secondarily Retroperitoneal*
Where does the transverse colon start and stop (spinal levels), and type of peritoneal?
- Starts at L1 and come across to end at the left colic (splenic) flexure at T12
- Intraperitoneal
What is the transverse colon attached to the wall by?
Transverse mesocolon
Describe the path of the descending colon w/ spinal levels and structures, type of peritoneal?
Starts at right colic (splenic) flexure at T12 and descends to about the crest of the hips at L4, before deviating medially (secondarily retroperitoneal)
What structure lies inferior to the 1st part of the duodenum?
- Head of pancreas
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What structures lie medial, anterior, and posterior to the 2nd part of duodenum?
Medial: Head of pancreas
Anterior: Gallbladder (fundus), Right lobe liver, and transverse colon
Posterior: Right kidney and ureter
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Which structures lie anterior and superior to the 3rd part of the duodenum?
Superior: Head of Pancreas
Anterior: Jejunum
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What spinal level does the sigmoid colon start at and where does it go; type of peritoneal?
- Starts at L5 and descends into the rectum
- Intraperitoneal
What are Taenia coli; produce what upon contraction?
- 3 bands of longitudinal muscle on the outsie of colon
- Produce haustrae (sacculations)
What are Omental (epiploic) appendices?
Tags of fat that are characteristic of the large intestine
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Where do you find the Appendix attached; supported by?
- Posterior-medial part of the cecum
- Junction of 3 taenia coli
- Supported by the mesoappendix
The sigmoid colon is attahced to the wall by what?
Sigmoid mesocolon
What are Diverticulosis; commonly found where?
- Little pockets/pouches in the sigmoid colon
What is Volvulus of Sigmoid colon?
- Rotation and twisting of the sigmoid colon
- Results in obstruction of the lumen proximal to the twisted segment
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What can Volvulus of the sigmoid colon lead to?
Constipation and ischemia of the looped part, may progress to fecal impaction and possible necrosis.
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What are the functional lobes of the left liver (roman numberals)?
Segment II: Left posterior lateral segment
Segment III: Left anterior lateral segment
Segment IV: Left medial segment
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What are the functional lobes of the right liver (roman numerals)?
Segment V: Right anterior medial segment
Segment VI: Right anterior lateral segment
Segment VII: Right posterior lateral segment
Segment VIII: Right posterior medial segment
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What is the Falciform ligament; contains which other ligament?
Ventral mesentery that connects the liver to the abdominal wall; contains the round ligament of the liver
Bare area of the liver is defined by which ligament?
Anterior, posterior, and left/right coronary ligaments
What is the Porta hepatis?
- Transverse fissure between the caudate and quadrate lobes of liver, transmits the portal triad
The ligamentum teres (round ligament of liver) is derived from what embryological structure?
Obliterated left umbilical vein
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The ligamentum venosum is derived from what embryologic structure?
Ductus venosus
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Where is the gallbladder found anatomically?
- Lies in Hepatic fossa
- Contacts anterior abdominal wall at 9th costal cartilage
What are gallstones called and composed of?
Cholelithiasis (made of cholesterol crystals)
What 3 places can gallstones get lodged?
1) Cystic duct
2) Hepatic duct
3) Hepatopancreatic ampulla
Blockage of the cystic duct with gallstones may result in, and what are the presenting sx’s?
- Cholecystitis
- Biliary colic: intense spasmodic pain
- Voluntary and involuntary guarding
- Positive Murphy’s sign
Where would the pain with blockage of the cystic duct w/ a gallstone be located?
- Tip of right 9th rib
- Referred pain to back and epigastric region
What happens with blockage of the hepatopancreatic ampulla w/ a gall stone?
- Bile duct and pancreatic duct both blocked
- Bile may backup into pancreas and cause pancreatitis
- Pt’s may also be jaundice
If a gallstone enters the intestine, where else might a blockage be caused?
A gallstone in superior part of the duodenum will move through the digestive tract and cause a blockage at the ileocecal junction
With a cholecysto-enteric fistula, which other organs may be affected?
- Superior part of the duodenum
- Transverse colon
Describe the duodenum (1st, 2nd, 3rd, and 4th parts) using the vertebral levels and planes
1st - L1 (transpyloric plane)
2nd - L3 (subcostal plane
3rd - L3 (subcostal plane)
4th - L2 (directed superiorly to the left side)
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Describe the roots of the mesentry using the verterbal level and planes
Starts to the left of L2 and ends at transtubercular plane lateral to the right side of the linea semilunaris at L5
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What plane and vertebral level is the Ileocecal valve?
Transtubercular plane, lateral to linea semilunaris at L5
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Where is the upper border of liver in relation to planes and vertebral levels?
Xiphisternal plane (T9/10) to left linea semilunaris
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Where is the lower border of liver in relation to planes and vertebral levels?
Right costal margin to tip of right 9th costal cartilage to tip of left 8th costal cartilage to upper border
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Where is the gallbladder in relation to planes and vertebral levels?
Tip of 9th costal cartilage at the tranpyloric plane (L1)
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Where is the head, neck and body/tail of pancreas in relation to planes and vertebral levels?
Head - L2 in C of duodenum
Neck - Left side of L1
Body and Tail - Neck to hilum of spleen, lateral to left semilunaris
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