Esophagus, Stomach_ Histology Flashcards
3 layers of mucosa
epithelium (varies by location) lamina propria (loose CT, vessels, lymph, nerves) muscularis mucosae (2 layers of smooth muscle--->fine movements of mucosa)
Submucosa
located on outer surface of muscularis mucosa
larger vessels, lymphatics, nerves, glands (depending on region)
contains meissners plexus (innervate muscularis mucoasae)
muscularis externa
2 layers of smooth muscle
inner circular
outer longitudinal
Auerbach’s plexus helps maintain tone and participates in peristalsis
adventitia
outermost coat of dense CT, blends with surrounding CT
serosa
membranous epithelial covering that surrounds the adventitia
i.e. MESENTERY —>HOLD LARGER VESSELS AND NERVES
esophagus histology
thick NK SS epi
contain cardiac esophageal glands (mucous)
well developed muscularis mucosae
muscularis externa (as you move down, you increase the amt of smooth muscle) **NO SEROSA**
cardioesophageal junction
transition from eso to stomach
sudden change from SS to Simple columnar
NOT a true sphincter, just muscularis externa
Stomach histology
simple columnar with invaginations to line gastric pits to allow some absorption
very thin muscularis mucosa
Surface mucous cells
columnar cells that cover the surface and in line gastric pits
secrete pH neutral mucus (NOT GOBLET)
Mucus neck cells
secrete acidic mucus which mixes with HCl, but still protects the epithelium
parietal cells
secrete HCl and intrinsic factor
have microvilli and canaliculi where HCl is secreted on apical surface
stains pink/red with dark nuclei
located within the lamina propria
Cheif cells
secrete enzymes found in gastric juice (pepsinogen—>pepsin) and lipase
enzymes are secreted at the base
pale staining, look like serous cells, basal nuclei
Microvilli
Gastric enteroendocrine cells
present throughout the entire GI tract
secrete at the base of the cell
gastrin, somatostatin, VIP, 5HT, GIP
Lie b/w BM and cheif cells, not all reach lumen
