Gross Anatomy of the Alimentary Tract Flashcards
The only ectoderm lined portions of the gut tube.
oropharynx and lower end of anal canal
Point that marks division between foregut and midgut.
Entry point of bile duct into duodenum
Point that marks midgut/hindgut division.
Between proximal 2/3 and distal 1/3 of transverse colon.
P/S innervation of foregut
Vagus
P/S innervation of midgut
Vagus
P/S innervation of hindgut
Pelvic nerves S2-S4
S innervation of foregut
T5-T9
S innervation of midgut
T10-T12
S innervation of hindgut
L1-L3
Purpose of sympathetic innervation of gut
to divert blood supply away from gut in a flight/fight situation
Preganglionic parasympathetic nerves to gut are long/short
long –> enteric ganglia are within walls of gut tube so postganglionic nerves are short
Thoracic and lumbar splanchnic nerves have collateral innervation provided by the ____
prevertebral ganglia
Postganglionic sympathetics reach the viscera via the _____
periarterial plexus
S fibers carry sensations of visceral pain back from the gut structures they innervate and refer them which dermatomes?
those dermatomes of the body wall that match the sympathetic innervation of the organ
T/F visceral pain is well localized
F –> referred pain so poorly localized
Secondary retroperitoneal viscera in abdomen
midgut portion of duodenum, pancreas (except tail), ascending colon, descending colon
3 synonyms for mesentery remnant
ligament, omentum, meso- (prefix)
3 constrictions of esophagus
cervical, thoracic (aortic arch and left atrium/left mainstem bronchus), diaphragmatic
Spinal level of cervical constriction of esophagus
C6
Spinal level of thoracic constriction of esophagus
T4
Spinal level of diaphragmatic constriction of esophagus
T11
The esophagus begins at what spinal level?
C6 –> also junction between larynx and trachea
Which muscle acts as a sphincter regulating movement of food/fluid into esophagus
cricopharyngeus
The esophagus crosses the level of the diaphragm at what spinal level?
T10
Muscle mix of upper 5% of esophagus
voluntary skeletal muscle
Muscle mix of middle 45% of esophagus
mixture of skeletal and smooth muscle (mostly smooth)
Muscle mix of distal 50% of esophagus
involuntary smooth muscle
Innervation of esophagus
Vagus –> both skeletal and smooth muscle
Three glandular divisions of stomach
cardiac, fundus, pyloric
4 anatomic divisions of stomach
cardiac, fundus, body, pylorus
Muscle of the inside of the stomach
rugae
The opening to the omental bursa/lesser sac is called the _____
epiploic foramen
Importance of epiploic foramen
transit point of vasculature, venous drainage, and biliary apparatus of gut to/from liver
Area of stomach between pyloric canal and body of stomach
pyloric antrum
Point that marks the distinction between pyloric canal and pyloric antrum.
Angular incisure/notch
Muscles of stomach
Outer longitudinal, middle circular, innermost oblique –> vs. most viscera which has only two muscle layers (eg. esophagus has outer longitudinal and inner circular)
Type of cells lining esophagus
stratified squamous
Type of cells lining stomach
simple columnar
Histologic point where squamous cells of esophagus give way to columnar cells of stomach
Z line @ level of T11
3 branches of celiac trunk
common hepatic, splenic, left gastric
Spinal level of celiac trunk
T12-L1
Spinal level of SMA
L1
Spinal level of IMA
L3
Dual blood supply of lesser curvature of stomach
L and R gastric arteries (from celiac trunk and proper hepatic arteries respectively)
Dual blood supply of greater curvature of stomach
L and R gastroepiploic arteries (from splenic and gastroduodenal [from common hepatic] arteries respectively)
Course of gastroduodenal artery and clinical correlate
arises from common hepatic and descends down posterior to first part of duodenum –> put at risk by ulcers of posterior duodenal wall
Blood supply of fundus of stomach
short gastric arteries (from splenic)
Innervation of stomach
vagus nerves: anterior vagal trunk/anterior esophageal plexus (previously L vagus) and posterior vagal trunk/posterior esophageal plexus (previously R vagus)
Portion of duodenum that is foregut
parts 1 and half of 2 prior to entrance of bile duct
Bile and pancreatic secretions drain into the 2nd part of the duodenum at the _____
major duodenal papilla
Plicae circulares
mucosal surface of jejunum have an array of circular folds vs smooth mucosal surface of ileum
Simple arcades, long vasa recta
jejunum
Complex arcades, short vasa recta
ileum
Strips of longitudinal muscle of large bowel
3 taenia coli
Outpocketings of large bowel
haustrations
Omental/epiploic appendages
Fat droplets that emanate from taenia coli
3 main branches of SMA
iliocolic, right colic, middle colic
Collateral blood supply of large bowel
marginal artery
3 main branches of IMA
left colic, sigmoidal, suprior rectal
Area of large bowel that is particularly vulnerable to ischemia
juncture of mid/hindgut where IMA and SMA branches anastamose
Internal anal sphincter is under voluntary/involuntary control
voluntary
