Gastric Motility and Pancreatic Function Flashcards
The enteric nervous system is under control by what systems?
Parasympathetic and sympathetic nervous systems
What is the main parasympathetic input to the enteric nervous system?
Vagus nerve
What is the main sympathetic input to the enteric nervous system?
Splanchnic nerve
What effect does the parasympathetic system have on the GI tract?
Stimulatory - increases secretion and motility
What effect does the sympathetic system have on the GI tract?
Inhibitory - except on salivation, decreases secretion and motility
Gastric acid in the duodenum is neutralised by _ which is secreted from _
Bicarbonate
Brunner’s gland duct cells
Bicarbonate combines with gastric acid to produce
Carbonic acid, which then breaks down to produce water and carbon dioxide
What three mechanisms control gastric acid secretion and how do they control it?
Neurocrine - vagus/local reflexes
Endocrine - gastrin
Paracrine - histamine
What will precursors to eating (sight, smell, taste of food) trigger in the stomach?
Acid production
What does stomach acid do to any bacteria ingested?
Instantly sterilises it
In what phase is stomach acid produced in response to precursors to eating?
Cephalic phase
Precursors to eating stimulate the vagus nerve which increases its stimulation of the stomach to release
ACh which stimulates the parietal cells to produce acid
Precursors to eating stimulate the vagus nerve which increases its stimulation of the G cells which produce
gastrin which stimulates parietal cells to produce acid
Gastrin in the stomach stimulates the ECL cells which
release histamine which stimulates the parietal cells to produce acid
Gastric acid secretion is also stimulated in what phase?
The gastric phase
