Histo Upper GI Tract

Question 1

mucosa

Answer 1

a lining epithelium w. mucosal and submucosal glands and ducts
an underlying lamina propria consisting of a vascularized loos connective tissue
a thin layer of smooth m, the muscularis mucosae

Question 2

epithelium of oral cavity oropharynx esophagus anal canal

Answer 2

stratified squamous

Question 3

epithelium of stomach SI LI rectum

Answer 3

simple columnar

Question 4

epithelium function

Answer 4

selective permeable barrier
transport, digestion, absorption
hormone production

Question 5

lamina propria

Answer 5

vascularized loose CT
lymphatic nodules and scattered immunocompetenent cells
in SI and LI is relevant site of immune response (peyers patch or GALT)

Question 6

muscularis mucosae

Answer 6

thin double layer of smooth m
increases contact area with food
propel and mix food in GI tract

Question 7

submucosa

Answer 7

dense irregular CT w/ large BV lymphatics and nn branching into the mucosa and muscularis
glands are present in esophagus and duodenum

Question 8

mucosa

Answer 8

stomach and SI both mucosa and submucosa extend into the lumen as folds
mucosa alone can extend into the lumen as fingers
mucosal glands increase the secretory capacity
vili increase the absorptive capacity of the digestive tube
significant variations from segment to segment of the digestive tract

Question 9

mucularis externa

Answer 9

circular layer - reduces the lumen

longitudinal layer - shortens the tube

Question 10

adventitia

Answer 10

outside peritoneal cavity
binds to the body wall
loose CT
BV and nn

Question 11

serosa

Answer 11

w/in peritoneal cavity
loose CT
simple squamous epithelium
BV, nn, adipose tissue

Question 12

extrinsic (ANS)

Answer 12

sympathetic - decrease motility/secretions

parasympathetic - increase motility/secretions

Question 13

intrinsic/enteric

Answer 13

distinct interconnected neuronal circuits
submucosal plexus (Meissner)
myenteris (Auerbach) - b/w inner and outer layers of muscularis externa
peristaltic contractions to move food bolus
secretory activity of mucosal/submucosal glands

Question 14

esophagus mucosa

Answer 14

non keratinized stratified squamous epithelium

non absorptive and friction resistant

Question 15

esophagus lamina propia

Answer 15

thin, elastic CT

upper muscularis mucosae contain elastic fibers

Question 16

lower esophagus

Answer 16

contains smooth m fibers

Question 17

esophageal glands

Answer 17

secrete a lubricating layer of mucus

Question 18

muscularis propria or extrena of esophagus

Answer 18

thick

transitions from skeletal m to smooth m

Question 19

clinical significance swallowing and dysphagia

Answer 19

UES - anatomically defined, cricothryroid
LES - functionally defined, gastroesophageal sphincter
GERD - change in epithelium to columnar

Question 20

Barrett’s esophagus

Answer 20

abnormal columnar epithelium replaces the stratifies squamous epithelium
predisposes to the development of adenocarcinoma of the esophagus

Question 21

stomach

Answer 21

rugae
gastric glands/pits
protective layer of mucous protects surface epithelium

Question 22

cardia region

Answer 22

simple tubular and coiled at the lower end

lined by mucus secreting cells

Question 23

mucous cells

Answer 23

surface mucous cells lining the pit
mucous neck cells located at the opening of the gastric gland into pit
produce mucins, glycoprotiens
produce HCO3 to neutralize microenvironment

Question 24

chief cells

Answer 24

lower 3rd of gastric gland

secret pepsinogen to digest proteins

Question 25

parietal cells

Answer 25

fundus-body of stomach

secrete hydrochloric acids and intrinsic factor

Question 26

autoimmune gastritis

Answer 26

autoantibodies to H/K dependent ATPase

destruction of parietal cells causes a reduction in HCl and lack of synthesis of intrinsic factor

Question 27

helicobacter pylori

Answer 27

found in mucus blanket lining, pyloric antrum

presence has been associated w. acid peptic ulcers and adenocarcinoma of the stomach

Question 28

gastoenteroendocrine cells

Answer 28

produce peptide hormones that work on the alimentary tube
regulation of water, electrolyte metabolism and enzyme secretion
regulation of gastrointestinal motility and mucosal growth
stimulation of the release of other peptide hormones

Question 29

secretin

Answer 29

released by the duodenal glands of Lieberkuhn
stimulates pancreatic and duodenal to release bicarbonate and fluid release
w/ CCK stimulates the growth of exocrine pancreas
stimulates chief cells to secrete pepsinogen
inhibits gastrin release which reduces HCl

Question 30

gastrin

Answer 30

produced by G cells in pyloric antrum
stimulate the production of hydrochloric acid by parietal cells
activate CCK to stimulate gallbladder contraction

Question 31

CCK

Answer 31

stimulates gallbadder contraction and relaxation of the sphincer of oddi

Question 32

glucose-depennent insulinotropic peptide

Answer 32

stimulates insulin release

Question 33

motilin

Answer 33

released every 90 minutes during fasting

stimulates GI motility

Question 34

ghrelin

Answer 34

produced in stomach fundus

leads to release of GH

Question 35

pylorus

Answer 35

simple tubular and branched at very lower end
pits are deeper
mucus secreting cells

Question 36

lamina propria of stomach

Answer 36

reticular and collage fibers

Question 37

sumbucosa of stomach

Answer 37

dense irregular CT

submucosal plexus of Meissner

Question 38

muscularis externa of stomach

Answer 38

circular
oblique
longitudinal