BIOL 2P97 Lecture Notes - Lecture 3: Vagus Nerve, Somatostatin, Gastrin
28 May 2016
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Document Summary
Large number of regulatory pathways that are involved. 2 main inputs of stimulatory events that start a whole cascade of what is happening. Food being physically present in the stomach; sensory neurons in the stomach. Input by the vagus nerve (cephalic response/ cephalic reflex: signals to a large number of neurons as well muscles in the stomach to signal, nerve response sent down from the brain, start to stimulate the production of gastrin. Together gastrin and histamine stimulate parietal cells to add in ph. So the physical input of food or the input from the vagus nerve/ cephalic reflexes initiate gastric secretion in the g cells. Both tend to turn on parietal cells to produce acid. Physical presence of food indirectly stimulates the production of acid: through the action of gastrin & histamine. Can also work in a negative feedback pathway so doesn"t want to be producing protons forever.
