生理学的概念及生命活动的特征 (25).ppt

Physiology1 I.Pancreatic juiceII.Bile secretionOutline13Pancreatic juicesecretinCCKAChHCO3-+H2ODuctual cells(H2O,HCO3-)Acinus cells(enzymes)Pancreatic ductHistology of the PancreasHCO3-+H2OComposition of Pancreatic JuicepancreasPancreatic juicePancreatic acini：pancreatic enzymes Epithelium of the ductules:H2O、HCO3 Exocrine glandsEndocrine glandsInsulin,glucogan，etc.BloodflowPancreatic ductMedical physiology:principles for clinical medicine/edited by Rodney A.Rhoades,David R.Bell.4th ed.Guyton and Hall Textbook of Medical Physiology.13th ed.-Aqueous Component of Pancreatic SecretionEnzymatic Component of Pancreatic SecretionEnzymes Substrate Hydrolytic actionTrypsinChymotrypsinElastaseproteins Breaks peptide bonds in proteins to form peptide fragmentsCarboxypolypeptidase proteins Splits off terminal amino acid from carboxyl end of proteinLipase fats Splits off two fatty acids from triacylglycerols,forming free fatty acids and monoglyceridesAmylase polysaccharides Splits polysaccharides into glucose and maltoseRibonucleaseDeoxyribonucleaseNucleic acids Splits nucleic acids into free mononucleotidesA Thought Question:Why couldnt the proteolytic enzymes digest the pancreas itself?Regulation of Pancreatic Secretion1)ACh:Production of large quantities of pancreatic enzymes but relatively small quantities of H2O and electrolytes3)Secretin：Stimulates secretion of large quantities of H2O and HCO3-2)CCK:Similar to AChsecretinCCKAChHCO3-+H2O Summary：Regulation of Pancreatic SecretionAmino acidsFatty acidsH+H+Amino acidsFatty acidsCCK SecretinAChPhysiology,6th edition Linda S.Costanzo