Regulation of gastrointestinal function Flashcards
Name the 2 plexuses involved in intrinsic (enteric) nervous and endocrine control.
Myenteric (auerbach’s) plexus
Submucosal (Meissner’s) plexus
Stimulation of the myenteric plexus causes?
Peristalsis, contractions along the whole GIT
Stimulation of the Meissner’s plexus causes?
Secretions
Name the 3 components of the intrinsic enteric nervous system
Meissner’s (submucosal) plexus
Myenteric (auerbach’s) plexus
Enteroendocrine cells in mucosa/ pancreas
Name and describe the 2 types of sensory (afferent) neurons.
Mechanoreceptors: within smooth muscle layers, measures gut distension
Chemoreceptors: within mucosa, measure chemical conditions in the lumen of the gut (e.g. peptides, pH)
Describe interneurons
Travel long distances within the MYENTERIC PLEXUS (AUERBACH’S PLEXUS) and connect the myenteric and submucosal (meissners) plexus
List the excitatory neurocrine neurotransmitters
Cholinergic (secrete Ach)
peptide substances
List the inhibitory neurocrine transmitters
Peptides - somatostatin
Nitric oxide, ATP
Name a dual purpose peptide and its actions
Vasoactive intestinal peptide (VIP) which inhibits smooth muscle, and stimulates
List the 2 true endocrine hormones., why are these considered true hormones
Somatostatin and gastrin, true hormones as they have to travel via blood
What do enterochromaffin cells secrete
Secretin
Explain the process of paracrine secretion.
Cell targeting a nearby cell (no blood required)
Explain the process of endocrine secretion.
Cell targeting a distant cell via a bloodstream
Explain the process of holocrine secretion.
Cell breaking apart to release its contents
What hormone acts as a paracrine molecule?
Somatostatin