Week 2.3 - Gastric Motility and Pancreatic Function Flashcards
What are peristaltic waves?
move food from body to antrum
What produces peristaltic waves and how many?
peristaltic rhythm - 3 waves per minute. produces by pacemaker cells in longitudinal muscle layer
stomach body muscle vs antrum muscle and how this effects mobility?
stomach body is thin so weak contractions.
antrum is thick with 3 layers - longitudinal muscle, circular muscle and oblique - powerful contractions
Why is it important that the antrum has powerful contractions?
to contract the sphincter to allow food into the duodenum
Why is contraction of the pyloric sphincter important?
- control acid into duodenum
- allows food to re-enter stomach for further mixing like cycles
What does it mean that the slow wave depolarisation is sub-theshold?
alone doesn’t produce enough waves to produce AP to cause contraction. must be paired with hormone/chemicals like ACh or gastrin
What determines if a contraction is strong or weak?
no. of action potentials - more=strong
What forms of control cause a stronger or weaker contraction?
neural or hormonal.
- neural is vagal/local ENS distending stomach, causing release of ACh.
- hormonal is ACh or gastrin
- ….or fats/amino acids in duodenum inhibit motility by releasing GIP/CCK/secretin
How is acid in the duodenum neutralised? 2 ways
- acid triggers vagal/ENS response, releasing bicarbonate from submucosal glands in duodenum.
- acid causes secretin release, increasing bicarbonate secretion.
What is the name of the duodenal gland which secretes HCO3-?
brunners gland duct cell
Where do the pancreas head and tail face?
head is in duodenum curvature. tail is towards the spleen
What endocrine activity do we see in the pancreas?
has pancreatic islets which have alpha cells secreting glucagon and beta cells secreting insulin, controlling metabolism
What exocrine activity do we see in the pancreas?
has acini cells which produce enzymes and hormones.
What is the journey from acini to duodenum?
acini, intracalated ducts, intercalated ducts, main pancreatic duct, combines with common bile duct, sphincter of oddi and then major duodenal papilla
What is the journey of pancreatic juice in the case of a defect in one of the pathways?
accessory pancreatic duct which takes pancreatic juice and bile into the lesser duodenal papilla