Digestive System- stomach Flashcards
mixing motility
= segmentation
propulsion/moving forward motility
= peristaltic
innermost tissue layer
mucosa
thick layer of CT and gland tissue.
contains larger lymph and blood vessels. contains nerve network
submucosa
inner layer of circular and longitudinal muscles, nerves organized into plexus. this layer regulates movment
muscular externa
serosa
outer layer, CT, fold to connect to mesentary
where are lymph nodes found
in mucosa layer
3 major salivary glands
parotid, submandibular, sublingual
cells on esophagus
stratified squamous ( then has the same 4 layers as in digestive tract)
rugae
disappear when stomach is full
pylorus
the furthest part of the stomach - by the pyloric sphincter
mucous neck cells secrete
mucus to protect against resin and acid
chief cells secrete
pepsinogen
parietal cells secrete
HCL
intrinsic factor
what does HCL do
activates pepsinogen and denatures other proteins
endocrine cells secrete
gherlin hormone
what secretes HCL
parietal cells
what secretes enzymes
chief cells
what secretes intrinsic factor
parietal cells
what secretes ghrelin
endocrine cells
3 layers of the mucosa layer
- membrane
- lamina propria
- muscular mucosa
lamina propria
thin layer of CT under the mucous membrane (2nd layer in mucosa layer)
GALT
gut associated lymphoid tissue ( found in the lamina propria
submucosa in stomach
has larger lymph and blood vessels
- nerve network - plexus
- thick layer of CT
muscular externa
major smooth muscle coat of digestive tube. usually 3 layers
- oblique, circular, longitudinal
serosa
secretes fluid to lubricate and prevent friction
mesenteries
double sheet of serious membranes
- stabilize and position organs
- provide network of vessels nerves and lymph to digestive tract
mixing in stomach takes place in
antrum of stomach
storage in stomach takes place in the
body of stomach
principle regulator in gastric emptying?
controlled by duodenum ( fat, acid, hypertonicity, distension)
- fat is slow- less emptying
-acid- needs to be neutralized in the duodenum ( high acidic meals take longer)
- hypertonicity- build up of aa and glucose slows
emptying
- distension- too much chyme in duodenum prevents more emptying
factors in the docdenum (fat, acid, distension, hypertonicity) can trigger either?
- neural response
2. hormonal response
neural response
enterogastric reflex that acts to slow the peristaltic activity
- smooth muscle contractions- autonomic system
hormonal response
release gastric inhibitory peptide (GIP) in response to (after factor in duodenum triggers less gastric emptying )which acts on gastric muscles to decrease peristalsis
three phases of gastric secretion
cephalic phase, gastric phase, intestinal phase
cephalic phase
thinking of food triggers release of gastric juice
- nerve mechanism through parasympathetic
gastric phase
distension of stomach triggers parasympathetic reflexes to increase gastric juice secretions
- nerve and hormal response bc gastrin ( hormone) is also secreted by G cells) which casues increased secretion of gastric juice
gastrin
hormone produced by endocrine G cells that promotes release of gastric juice
intestinal phase
triggers endocrine response
- food enters the SI, stomach activity is decreased by gastric inhibitory peptide (GIP), CCK and secretin
which hormones oppose the action of gastrin
CCK, GIP and secretin - these stimulate ejection of bile from pancreas
2 areas that secrete gastric juice
oxyntic mucosa and pyloric gland area
where do the digestive hormones come from?
oxyntic mucosa which contains gastric glands that have endocrine, chief, parietal and ECL cells
what are exocrine cells
secrete through ducts
- mucous, chief, parietal
- found in the oxyntic mucosa
ECL
endocrine cell dominant in the oxyntic mucosa : secretes histamine which stimulates parietal cells
cells in the pyloric gland area
mucous, G cells and D cells
G cells
gastrin
gastrin
stimulates exocrine cells
D cells
inhibitory secretions - somatostatin
- inhibits G cells, parietal cells and ESL cells
what casues 60% of ulcers
helicobacter pylori which creates alkaline envirment around it to stay alive
what can prevent HCL formation
proton pump inhibitors
adventitia
CT outer layer of esophagus
duct cells
pancreas secrete buffer
