Gross Anatomy of Alimentary Tract Flashcards
Parasympathetic innervation of the foregut, midgut, and hindgut?
Foregut: Vagus nerve
Midgut: Vagus nerve
Hindgut: Pelvic nerves (S2,3,4)
Sympathetic spinal nerve levels for each foregut, midgut, and hindgut?
Foregut: T5-T9
Midgut: T10-T12
Hindgut: L1-L3
What functions do the sympathetics have in the gut?
Diverting blood away.
Important for referred pain.
3 different types of mesentery remnants?
Ligaments
Omentum
“Meso-“ things (eg. mesocolon)
What’s the role of the cricopharyngeus muscle?
Acts like a sphincter at the top of the esophagus (at the cervical constriction).
3 areas of constriction of the esophagus? (Approximate spinal cord levels?)
Cervical constriction - C6
Thoracic (aka broncho-aortic) - T4
Diaphragmatic (aka LES) - T11
What kind of muscle is in the esophagus? What nerves control it?
Skeletal at the top, smooth for most of it.
It’s all vagus nerve innervation.
4 anatomic divisions of the stomach?
Cardiac Fundus Body Pylorus (Fundus and body aren't distinguished histologically)
What muscle layer does the stomach have that other parts of the gut don’t?
The innermost oblique - helps grind things up.
At what level is the esophageal hiatus? What else is there?
T10 - that’s also where the esophageal sphincter is.
How does the mucosa change from esophagus to stomach? What is this called?
Changes from squamous epithelium to columnar. The transition is called the Z-line because it’s zig-zagged.
If you get a perforating ulcer through the posterior wall of the stomach, where will the contents end up?
They’ll end up int he lesser sac (aka. omental bursa).
Review: 3 major branches of the celiac trunk?
Left gastric a.
Common hepatic a.
Splenic a.
What is the dual blood supply of the lesser curvature of the stomach?
Left gastric a.
Right gastric a. (comes off the common hepatic a.)
What is the dual blood supply of the greater curvature of the stomach?
L. gastroepiploic a. (off of splenic a.)
R. gastroepiploic a. (off the gastroduoenal a. off the common hepatic a.)
Where do the left and right vagus nerves go around the the level of the stomach?
Left becomes anterior vagal trunk / plexus.
Right becomes posterior.
What vessels run between the head/neck of the pancreas and the duodenum?
Superior mesenteric a.
Superior mesenteric v.
When looking at it from inside, what is the name of the structure where the ampulla of vater drains into the duodenum?
The major duodenal papilla.
What are the big ridges in the jejunum called?
Plicae circularis.
How does the ileum vary grossly from the jejunum, on the inside?
The luminal surface is much smoother in the ileum.
Review: How does the configuration of the vasa recta vary between jejunum and ileum?
Jejunum: simple arcades, long vasa recta.
Ileum - complex arcade, short vasa recta.
(shorter name, shorter vasa recta?)
What’s the longitudinal muscle of the colon?
Tenia coli…
From supplying proximal bowel to distal bowel, what are the 3 major branches of the SMA?
Ileocolic a.
Right colic a.
Middle colic a.
(jejunal aa. feed vasa recta of the jejunum)
From supplying proximal bowel to distal bowel, what are the 3 major branches of the IMA?
Left colic a.
Sigmoid aa.
Superior rectal a.
What is the artery running parallel to the colon with lots of collateral blood flow called?
The marginal a.
Review: Which area of the colon is most susceptible to ischemia when blood pressure drops?
The junction between midgut and hindgut (2/3 along the transverse colon), as this is at the end of each the SMA’s and IMA’s domains.
Should you be pretty familiar with the radiology stuff here?
Yeah…
