C12: GI Tract Flashcards
What is the esophagus and where does it pass though the diaphragm
Where does it enter the stomach
- muscular tube going from the pharynx to the GE junction
- passes through hiatus of diaphragm at T10 and enters the superomedial aspect of the stomach (cardia)
What is the hiatus of the diaphragm formed by
The R crus of the diaphragm
What’s the relationship of the esophagus to the AO
Anterior
The GE junction marks the juncture of what structures of the stomach
The greater and lesser curve
Where is the stomach located in the abdo
L hypochondrium and epigastric regions (lower aspect crosses midline and ends at the duodenum)
Where is the cardia of the stomach found?
What is the fundus of the stomach?
Body?
Pylorus?
Cardia: surrounds lower esophageal sphincter
Fundus: rounded most superior part of stomach (L of cardia)
Body: central portion
Pylorus: distal aspect of stomach
Where will the pylorus lie with an empty stomach?
Full?
Empty: just R of midline
Full: may shift even more to R of midline
Which part of the sm bowel is the widest and most fixed
Duodenum
What are the 4 parts of the duodenum and all of their different names
- First part/Superior/Bulb
- Second/ descending
- Third part/transverse
- Forth part/ascending
Describe the location of the 1st part of the duodenum.
- intraperitoneal
- runs from neck of the pylorus up and backwards to the level of the GB
which structures empty into the 2nd part of the duodenum.
CBD and main panc duct
Which areas of the abdo are retroperitoneal
2nd to 4th part of the duodenum
The jejunum leaves the retro peritoneum and becomes intra peritoneum at which ligamentum
Suspensory ligament/ligament of Treitz
What’s the function of the ligamentum of Treitz
Attaches duodenum to the diaphragm
How’s the jejunum arranged and which regions of the body does it occupy
-arranged in multiple loops and occupies the umbilical and L iliac regions
Which part of the small bowel is the longest?
Where does it join the large intestine
Ileum
A the ileocecal sphincter (valve of the sm bowel/lg bowel junction)
Which regions of the abdo does the ileum occupy
Umbilical, hypogastric, R iliac and pelvic regions
What structure anchors the ileum and jejunum to the post. Abdo wall
Mesentary
Where in the abdo is the cecum located
In the retroperitoneum
- in RLQ and/or R iliac region
- sits below ileocecal sphincter at het origin of the ascending colon
(Pouch like portion)
Which structures extends from the inferior portion of the cecum
Appendix
What is the appendix
Blind ended tub that opens into the cecum
What DI modalities are best to see the appendix in children and adults
Adults: CT
Children: US
Which area of the body is the ascending colon and how does it run?
Retroperitoneum
-runs in a superior path along the R flank… from the R iliac fossa to the visceral surface of the R lobe of liver
What does the hepatic flexure connect? Which structure does is get in the way of imaging
- connects the ascending and transverse colon
- 90 degree curse in the RUQ
- makes it hard to image the R kidney
Where’s the transverse colon located?
How does it travel w/ reference to the duodenum
Intraperitoneal
Anterior
Which colon extends over the pelvic brim
Descending colon… it runs from the L side of the abdomen to the L iliac fossa
Where does the sigmoid colon end?
It sits anterior to which structure
- terminal end of the colon
- sits anterior to the sacrum and projects inwards towards the midline
When does the rectum become the anal canal
When it penetrates the levator ani muscle
What are the 4 histological layers of the GI wall
Mucosa
Submucosa
Muscularis
Serosa
Describe the mucosal layer of the GI lining
- inner most layer composed of epithelial lining, c-tissue and muscle
- protects, absorbs and secretes
Describe the submucosal layer of the GI lining
- made of c-tissue, contains blood vessels and lymphatics
- nourishes surrounding tissue and transports absorbed nutrients
Describe the muscularis layer of the GI lining
- smooth muscle arranged in circular and longitudinal groups
- responsible for parastalsis
Describe the serosal layer of the GI lining
-outer layer for protection
the rugae of the stomach run along which axis of the stomach
do we see the rugae when stomach is distanded
parallel to the long axis.. they function to increase SA and allow for expansion
-no
what are the characteristics fold that we see in the small bowel
do they disappear when distended?
how far apart are they
valvule conniventes (circular folds)
- dont disappear when distended
- 3-5 mm apart
where are the valvule conniventes most prominent
in the duodenum and first half of the jejunum… not often seen the the ileum
what are the characteristics fold that we see in the large bowel… what are they formed by
how far apart are they
- haustral markings… due to 3 short muscle bands that cause the colon to pucker into sacculations
- 3-5 cm apart
what does the term ‘gut signature’ refer to?
the layers appearance of the gut (any area of the GI tract) on US due to the different acoustic properties of the histological layers o the GI tract.
describe the echogenicity of the layers of the gut
Lumen: hyper echoic Mucosa: hypoechoic Submucosa: hyper echoic Muscularis: hypo echoic Serosa: hypo echoic
describe the appearance of the gut wall (not echogenicity)… including thickness
what are we assessing the bowel for?
-should be uniform and compressible
Avg sign wall thickness (measure from lumen to wall):
- 3 mm distended
- 5 mm (non distended)
+ movement, diameter and contents
what is the keyboard sign?
what are haustral makings?
- valvular conniventes of the duodenum and jejunum
2. ascending and descending colon
what are the primary functions of the GI tract
- digestion and absorption of nutrients
- also the largest endocrine gland
where are the endocrine cells of the GI tract located
in the mucosa
what are the 3 hormones release by the GI tract?
what organ releases them and what are there functions?
- Gastrin:
- released by the stomach
- stimulates secretion of gastric acid - Cholecystokinin:
- related by the duodenum into the blood after fatty food and controls the contraction of the GB - Secretin:
- released by the duodenal mucosa and stimulates the secretion of bicarbonate from the panc
- decreases acid content
what are the arteries that supply the Sm and Lg bowel
how is blood drained from the Sm and Lg bowel
- celiac artery, and superior and inferior mesenteric arteries
- through the portal system
the gastric artery and vein supply/drain which organ
stomach
what does it indicate if theres symmetrical thickening of the GI lining?
asymmetrical?
w/ these conditions, will the bowel be compressible?
- inflammation (wont be compressible)
- malignancy (wont be compressible)
what can lead to excessive amount of fluid in the GI tract
- hypersecretion
- mechanical obstruction
- paralytic ileus (paralysis of the bowl, usually temporary)
when would activity of the bowl be increase of decreased
increased: early mechanical bowel obstruction or inflammation
decreased: paralytic ileus or end stage mechanical obstruction
should bowel gas typically be displaceable?
yes