GUT PHYSIOLOGY Secretion 2 Dr. Jack Grider Rm 12-004 Sanger Hall 828-1853 jgrider@vcu.edu 2009
Secretion: Gastroduodenal Junction
Secretions at the Gastroduodenal Junction PANCREATIC: -Serous component: Water and bicarbonate ion -Protein component: pancreatic enzymes BILIARY -Serous component:Water and bicarbonate -Protein & other: bile and related secretions INTESTINAL: -Serous: Water and electrolyte
Secretion:Pancreas Endocrine portion insulin, somatostain, glucagon, pancreatic polypeptide Exocrine portion water, electrolyte, enzymes
Secretion: Exocrine Pancreas
Secretion: Exocrine Pancreas: serous
Secretion: Exocrine Pancreas: Protein Storage in membrane bound zymogen granules Storage as pro-enzymes Trypsin inhibitor Acidification of granule Initial activation by enterokinase
Secretion: Exocrine Pancreas Enterocyte Gut Lumen Pancreas
Secretion: Exocrine Pancreas Proteases (75%) endo & exo trypsin Amylase Lipases Phospholipase cholesterol ester hydrolyase Other enzymes nucleases, elastases, etc Other proteins procolipase, trypsin inhibitor
Secretion: Control Mechanisms Neural Hormonal major multiple hormones Interactions
Secretion-Exocrine Pancreas: Neural Control
Secretion: Hormonal control Secretin: water and Bicarbonate ion CCK: enzyme component -multiple stimulants of CCK -interactions with neural control PP & PYY: inhibitory control.
Secretion: Exocrine Pancreas Regulation by secretin
Secretion: Exocrine Pancreas Regulation by CCK 6
Secretion: Exocrine Pancreas Regulation by CCK 7
Secretion: Exocrine Pancreas PP & PYY
Secretion: Exocrine Pancreas
Secretion: Exocrine Pancreas
Secretion: Intestinal Goblet cells: mucus Duodenal Glands: water & bicarbonate ion Enterocyte -villus migration (6 days) -secretory cells in crytps -water and chloride ion -cystic fibrosis transmembrane regulator (CFTR channel) and ClC2 channel CFTR Channel Nutrient Absorption (Carriers) Basolateral Sodium Pump CFTR Nutrient carriers Basolateral Na pump
Secretion: Intestinal ClC2 Cholera Tx
Secretion: Intestinal Enteric neurons from the submucosal plexus project all the way to the tip of the villus and innervate mucosal cells. Both sensory and motor neurons innervate the villus and crypt cells
Secretion: Intestinal Enteric neurons from myenteric and submucosal plexus, and extrinsic neurons from the sympathetic and parasympathetic nervous system regulate secretomotor neurons (VIP & Ach) and secretory reflexes. SSt, Opioid and SNS inputs are inhibitory; cholinergic are excitatory.
Secretion