Gastric function Flashcards
5 gastric functions
- reservoir
- begins digestion (breaks food into small 2mm)
- delivers food to duodenum
- produces gastric juice
- protects against micro-organisms
3 muscle functions of stomach
- receptive relaxation
- trituration - making chyme
- emptying
where is cutoff to 2 different glandular mucosa of stomach
between body and antrum
2 main types of stomach glands
- oxyntic - body and fundus
2. plyoric
6 cell types of oxyntic glands - and secretions
- surface cells
- mucous neck cells
- enterochromaffin cells - histamine
- D cells - somatostatin
- parietal cells - acid
- chief cells - pepsinogin
what is a paracrine cell
cell that affects the actions of the cell next to it
special cell of pyloric gland
G cell - gastrin
how does parietal cell work
CO2 + H2O become H2CO3 > H + HCO3-
H is secreted into stomach by K/H ATPase and HCO3 into blood
3 main signals of gastric acid production
- gastrin
- histamine
- acth
function of histamine
produced by ECL cell to tell parietal cell to secrete acid
function of gastrin (2)
- directly tell parietal cell to secrete acid
2. tells ECL to secret histamine
function of ACTH (3)
- tells parietal cell to secrete acid directly
- stims G cells
- stims ECL cells
what stims gastrin production (4)
- antral ditension (full)
- AAs
- vagal stim - see food
- rising pH
what stims histamine release (2)
- gastrin
2. vagal nerve
how is acid secretion inhibited in stomach?
- low pH
- stims D cell to release somatostatin
- somatostatin is inhib to G cells
- gastrin lowered
how is acid secretion inhibited by duodenum?
enterogastric reflex
- food in duodenum
- secretin and CCK released from duod.
- CCK stims somatostain and inhib gastrin
- secretin inhibs gastrin and parietal cells directly
3 places gastric acid signalling comes from
- cephalic (20%
- gastric 70%
- duodenum 10%
what is mucosal barrier
- mucus by mucous cels stimulated by food contents
2. epithelium secretes alkaline fluid in and stuck inmucous to protect stomach lining
function of gastric pepsin
primary protease
what stims gastric pepsin
ACH along with acid
what does chief cell secrete
pepsinogen - cleaved to pepsin by acid
function of intrinsic factor
binding of B12 for absorbtion
function of gastric lipase
hydrolysis of triglycerides
what is absorbed in stomach
very little - alcohol and ASA
