GI tissue Flashcards
4 layers of GI
- Mucosa
- Submucosa
- Muscularis externa
- Serosa
3 components of mucosa
Epithelium
Lamina propria
Muscularis mucosa
GALT located in
Lamina propria of mucosa
2 layers of muscle in muscularis externa
Inner ciruclar
Outer longitudinal
Meissner’s plexus
- interconnected network of ganglia and nerves located in submucosa
- Responsible for intrinsic motility of the lining of GI tract
Auerbach’s plexus
network of neuronal ganglia located between 2 muscle layers of muscularis externa
Cells/function located in body and fundus of stomach
- Mucus cells
- Cheif cells: secrete pepsinogen and lipase precursor
- Parietal cells: Secrete HCl and intrinsic factor
- Enteroendocrine cells
Cells of pylorus of stomach
- Mucous cells
- Parietal cells
- EE cells
Brunner glands found in
Duodenum
Cells/function in dueodenum
- Goblet cells: Secrete acid glycoproteins that protect lining
- Paneth cells: granules that contake lysozyme
- EE cells
HCL secretion stimulated by
Gastrin
ACh (from Vagus)
Histamine
HCl inhibited by
Low pH
Prostaglandins
Chyme in duodenum via GIP and Secretin
Pepsinogen secretion simulated by
- ACh (from vagus)
- Gastrin
- HCl
Gastrin secretion stimulated by
- Small peptides/aa
- Vagus (via GRP)
- Stomach distention
CCK source
I cells of duodenum and jejunum
CCK secretion stimulated by
- Fatty Acids, monoglycerides
- Small peptides and AA
Action of CCK
- Stimulates GB contraction and relaxes sphincter of Oddi
- Increase pancreatic enzyme secretion
- Inhibits gastric emptying to aid in digestion
Secretin source
S cells of duodenum
Secretin secretion stimulated by
Decrease pH in duodenal lumen
FA in duodenal lumen
Action of Secretin
- Increase pancreatic HCO3 secretion
- Increase bile production
- Decrease gastric H secretion
GIP source
K cells of duodenum and jejunum
GIP secretion stimulated by
- Glucose
- FA
- AA
Action of GIP
Increase insulin release
Decrease gastic H secretioin