Gastric Motility and Pancreatic Function Flashcards
Travel of peristaltic waves
From body to antrum
Structure of body
Thin muscle
Weak contraction
No mixing
Structure of antrum
Thick muscle
Powerful contraction
Mixing
Chyme
Gastric contents
Peristaltic rhythm
Generated by pacemaker cells
Motility under neural/hormonal control
Gastrin
Distension of stomach wall
Fat/acid/amino acid/hypertonicity in duodenum
Gastrin
Increases contraction
Distension of stomach wall
Long/short reflexes leading to increased contraction
Fat/acid/amino acid/hypertonicity in duodenum
Inhibition of motility
Neutralisation of acid in duodenum
Bicarbonate secreted by Brunner’s gland duct cells (submucosal glands)
Acid in duodenum triggers
Long and short reflexes to secrete HCO3
Release of secretin
Long reflexes
Vagal reflexes
Short reflexes
ENS reflexes
Secretin release from
S cells in duodenum
Secretin triggers release of
HCO3 from pancreas/liver
Negative feedback control (secretin)
Neutralisation of acid inhibits secretin release
Function of exocrine pancreas
Secretion of bicarbonate by duct cells
Secretion of digestive enzymes by acinar cells
Zymogens
Prevents autodigestion of pancreas
Inactive granules of digestive enzymes stored by acinar cells
Enterokinase
Converts trypsinogen to trypsin
Trypsin
Converts zymogens to active forms
Categories of pancreatic enzymes
Proteases Elastases Nucleases Phospholipases Lipases α-Amylases
Proteases
Cleave peptide bonds
Nucleases
Hydrolyse DNA/RNA
Elastases
Collagen digestion
Phospholipidases
Phospholipids to fatty acids
Lipases
Triglycerides to fatty acids+ glycerol
α-Amylases
Starch to maltose + glucose
Bicarbonate secretion stimulated by
Secretin
Secretin released in response to
Acid in duodenum
Zymogen secretion stimulated by
Cholecystokinin (CCK)
CCK released in response to
Fat/amino acids in duodenum
