Gastric Motility and Pancreatic Function Flashcards
Is the peristaltic contraction in the body of the stomach made by thin or thick muscle and what is the strength of it’s contraction?
Thin muscle - weak contraction
Is the peristaltic contraction in the antrum of the stomach made by thin or thick muscle and what is the strength of it’s contraction?
Thick muscle - powerful contraction
What part of the stomach does mixing occur in?
Antrum
What is chyme?
Gastric content
What is the peristaltic rhythm (No/min)
3/min
What generates the peristaltic rhythm?
Pacemaker cells from the longitudinal muscle layer
How do peristaltic slow waves occur?
Spontaneous depolarisation/repolarisation
What is the slow wave rhythm known as?
The basic electrical rhythm (BER)
Where are slow waves conducted through?
Gap junctions along the longitudinal muscle layer
What determines the strength of contraction for the slow waves?
The number of action potentials per wave
What are 2 examples of neural/hormonal control that increase the contraction of slow waves?
Gastrin
Distension of stomach wall (activates long/short reflexes)
Where is bicarbonate (HCO3) secreted from in the duodenum?
Brunner’s gland duct cells (found in the submucosa)
What is the function of HCO3 in the duodenum?
To neutralise acid
What are the 2 mechanisms of HCO3 secretion that acid in the duodenum triggers?
Long (vagal) and short (ENS) reflexes
Release of secretin from S cells
What are the 3 parts of the pancreas?
Head
Body
Tail
Where is the head of the pancreas located within?
The curvature of the duodenum
Where does the tail of the pancreas extend towards?
The spleen
What is the endocrine portion of the pancreas?
The pancreatic islets (islets of Langerhans)
What 3 substances are produced by the islets of Langerhans in the pancreas?
Insulin
Glucagon
Somatostatin
What is the exocrine portion of the pancreas?
Aciner cells (which form the lobules)
What do aciner cells produce?
Pancreatic enzymes
What allows the pancreatic enzymes to move out from the lobules?
Intercalated ducts
Describe the route from the intercalated ducts to the main pancreatic duct?
intercalated duct - intralobular duct - interlobular duct - main pancreatic duct
Which cells in the pancreatic islets secrete glucagon?
Alpha cells
Which cells in the pancreatic islets secrete insulin?
Beta cells
Where are the products of the pancreatic islets transported to?
The bloodstream
How are the digestive enzymes in the acinar cells stored as?
Inactive zymogen granules
Why is it important that the enzymes are stored as inactive zymogen granules?
Prevents autodigestion of the pancreas
What does enterokinase (pancreatic digestive enzyme) convert?
Trypsinogen to Trypsin
What is the role of trypsin?
Converts zymogens to their active forms
