Structure + Fnx Upper GI (2) Flashcards
There is sharp change from a _______epithelium to a _______epithelium dedicated to secretion at the junction of the esophagus and stomach.
stratified squamous
simple columnar
Although there are no anatomical sphincters in the esophagus, there are two physiological
sphincters:
— pharyngoesophageal sphincter prevents reflux from esophagus into the pharynx
— gastroesophageal sphincter prevents reflux from the stomach into the esophagus
The stomach is a _______ between the intestine and
esophagus where food undergoes mechanical and
chemical digestion to form_____.
dilated sac
chyme
Mucosa and submucosa are arranged as prominent folds
called______ in the empty stomach;
holds ~ _____ by distending
rugae
1.5 liters
Churning food in gastric juice which includes:
hydrochloric acid and digestive enzymes including pepsin, rennin, and gastric lipase
_____- small area at gastroesophageal junction
______- upper left to cardia; secrete acid and enzymes
cardia
fundus
- central area of stomach; secrete acid and enzymes
_____- constricted region at base; regulates release of
chyme into duodenum (pyloric sphincter); secretes
gastrin
body (corpus)
pyloris
Epithelium in stomach mucosa
Epithelium: Simple columnar epithelium
The epithelial cells lining the lumen generate a thick mucous (visible mucous) covering that functions to:
traps bicarbonate ions (alkaline) and protects the mucosa from the low pH in the stomach; soluble mucous acts as a lubricant.
Stomach mucosa invaginates into the lamina propria forming
gastric pits (GP)
secrete histamine in response to the vagus nerve to increase acid secretion
Enterochromaffin-type cells
Muscularis mucosae (MM): smooth muscle; gastric glands extend to MM influences
gastric gland outward flow
Thick layer of dense connective tissue
Numerous wandering cells including
lymphocytes, eosinophils, mast cells, and
plasma cells
Stomach Submucosa (S):
Numerous wandering cells in submucosa include
lymphocytes, eosinophils, mast cells, and
plasma cells, May also have adipose cells
Muscularis Externa has what 3 layers?
(O, C, L):
Three layers of smooth muscle
circular and longitudinal always present
oblique fibers may also be present
contraction controlled by myenteric
(Auerbach’s) plexus between layers
The surface of the mucosa is pitted with indentations called
gastric pits.
Gastric glands are________ of epithelial cells. One to seven gastric glands open into each gastric pit.
tubular columns
Gastric pits are divided into 3 regions:
isthmus, neck, base
different epithelial cell types in each region
Gastric glands are made of a
simple columnar epithelium that
consist of 6 cell types
- Surface mucous/lining cells
(gastric pit) - Parietal (oxyntic) cells (isthmus,
neck, and base) - Neck mucous cells (neck and
base) - Chief (zymogenic, peptic) cells
(base) - Enteroendocrine cells (base)
6.Stem (regenerative) cells (neck)
The mucous in ________cells is
thick and dense while the mucous
secreted by ______cells is soluble
surface lining
mucous neck