Download Secretion - eCurriculum

GUT PHYSIOLOGY
Secretion 2
Dr. Jack Grider
Rm 12-004 Sanger Hall
828-1853
[email protected]
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
CFTR
Nutrient
Absorption
Nutrient
(Carriers)
Basolateral
Sodium
Basolateral
Pump
carriers 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