Gastric Motility and Pancreatic Function Flashcards
Describe the direction of motion of peristaltic waves in the stomach
From body to antrum
Describe the musculature of the the body of the stomach?
Thin muscle therefore weak contraction and no mixing
Describe the musculature of the antrum
Thicc powerful muscle therefore powerful contraction causing contents to mix
What is the process of mixing and emptying of the stomach?
- Mixing
- Contraction of the pyloric sphincter
- Small quantity of chyme (gastric contents) enters duodenum
- Further mixing as astral contents is forced back towards body
How many contracts are there of the stomach per min on average?
3
How are the slow depolarisations achieved?
Spontaneous depolarisation/repolarisation conducted through gap junctions along longitudinal muscle - slow wave polarisation sub-threshold requires further depolarisation to induce contraction
Motility is under neural and hormonal control - outline three stimuli
Gastrin and distention of stomach wall induce long/short reflexes to increase contraction
Fat/amino acid/hypertonicity in duodenum inhibit contraction
What salt is responsible for neutralisation of gastric acid?
Bicarbonate (HCO3)
What glands secrete bicarbonate?
Brunner’s Gland duct cells (submucosal glands)
Acid in the duodenum triggers what three responses?
Long (vagal) and short (ENS) reflexes alongside secretin secretion from S cells which all cause HCO3 release from liver and pancreas
What are the three parts of the pancreas?
Head
Body
Tail
Where is the head of the pancreas located?
Within the curvature of the duodenum
Describe the endocrine functions of the pancreas
Pancreatic islets (of Langerhans) control secretion of insulin and glucagon Also Somatostatin which helps to control insulin and glucagon
Describe the exocrine functions of the pancreas
Acinar cells arrange in lobules contain digestive enzyme precursors (zymogens)
Why are digestive enzyme stored in the acinar cells as precursors?
To avoid autodigestion
