Gastric Motility and Pancreatic Function Flashcards
How is a peristaltic rhythm generated along pacemaker cells within the longitudinal muscle layer ?
Conducted through gap junctions along the longitudinal muscle layer
What determines the strength of muscle contractions i the small intestine ?
The number of action potentials
What are the submucosal glands found within the duodenum ? and what do they secrete ?
Brunner’s Gland Duct Cells secrete Bicarbonate
Which hormone is essential for maintaining the duodenal environment ?
Secretin
Where is the endocrine portion of the pancreas found and what is excreted ?
In the tail of the pancreas
Insulin, glucagon and somatostatin
What does the exocrine portion of the pancreas consist of ?
Acinar cells within the lobules of the pancreas.
How are the lobules within the pancreas connected to the pancreatic duct ?
via interlobular ducts
The interlobular ducts secrete what ?
Bicarbonate
What is the digestive aspect to the acinar cells within the pancreas ?
Digestive enzymes are stored in an inactive form within the pancreas (zymogen granules)
What are zymogens and what do they do ?
Inactive form of trypsinogen and they are inactive digestive enzymes which in their inactive form prevent the auto-digestion of the pancreas.
What converts zymogen granules from its inactive form to its active form and what is its active form ?
Trypsin
Trypsinogen
How is Trypsinogen converted to trypsin ?
By enterokinase found bound to the brush border of the duodenum
What do proteases do ?
Cleave peptide bonds
What do nucleases do ?
Hydrolyse DNA/RNA
What do elastases do ?
Collagen digestion
What do phospholipases do ?
Phospholipids to FA
What do lipases do ?
Tryglycerides to FA and Glycerol
What do alpha amylases do ?
Starch to maltose and glucose
What stimulates zymogen secretion ?
CCK
What does Gastrin do to contractions ?
Increases them
Where are Brunner’s Gland Duct Cells found ?
Within the duodenum
What cells within the duodenum secrete Bicarbonate ?
Brunner’s Gland Duct Cells
What hormone is essential for maintaining the duodenal environment ?
Secretin
What is secreted in response to acid within the duodenum ?
Secretin
From which cells in the duodenum is Secretin released ?
S Cells
What part of the pancreas secretes Bicarbonate ?
The duct cells
Which part of the pancreas secretes enzymes ?
The Acinar Cells
What converts Trypsinogen to Trypsin ?
Membrane bound enterokinase on the brush border of the duodenum
When is CCK released ?
When there are amino acids or FA’s present within the duodenum
The re;ease of CCK is under what type of control ?
Neural control (vagal and local reflexes)
Where is CCK secreted from ?
It is synthesised and secreted by the enteroendocrine cells in the duodenum
