Gastric motility and pancreatic function Flashcards
How does a food bolus move from the mouth to the stomach?
Peristaltic waves move it down the oesophagus
LOS relaxes
Receptive relaxation of stomach muscles as bolus enters
What is the antrum?
Bulbous bit at the caudal end of the stomach
Mixes matter
Thick muscle
Pyloric sphincter controls stuff leaving the stomach
What controls the peristaltic rhythm of the stomach?
Pace maker cells in the longitudinal muscle layer
Electrically connected via gap junctions
What determines the strength of peristaltic waves?
Frequency of waves on top of basic electrical rhythm (BER)
What is the BER?
Basic Electrical Rhythm
Spontaneous depolarisation and repolarisation of pacemaker cells which sets the frequency of contraction in the GI tract
What is the effect of gastrin on contraction?
Increases
What is the effect of stomach wall distension on contraction?
Increases
What is the effect of increased fat, acid, amino acid or tonicity on contraction?
Decreases
How does the duodenum protect itself from acidic corrosion?
Releases bicarbonate from Brunner’s gland duct cells in the submucosa
Does not have any high bicarbonate mucus secretion
How is the release of bicarbonate from submucosal glands in the duodenum stimulated?
Secretin from S cells in submucosa
What are the islets of Langerhans?
Endocrine part of the pancreas
Produces insulin, glucagon and somatostatin
What are acinar cells?
Exocrine part of the pancreas
Produce and transport enzymes which are passed into the duodenum to aid digestion
What controls passage of bile and pancreatic juice into the duodenum?
Sphincter of Oddi
What are zymogens?
Inactive stored form of digestive enzymes from the pancreas
Prevent autodigestion
What is enterokinase?
Membrane bound kinase in the duodenum
Converts trypsinogen to trypsin
