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Flashcards in Pancreas Deck (12):

describe the structure of insulin

  • A chain and B chain are connected by disulfide bonds
  • The C peptide (connecting peptide) connects the A and B chain


what is the clinical signifiance of C peptide?

Measurement of C peptide is clinically useful to measure the amount of endogenous insulin as it is not metabolized by the liver


describe signaling pathway in the pancreatic beta cell

  • GLUT 2 receptor = low affinity
    • high amount of glucose = entry through transporter
  • Glucose converted into G6P via glucokinase
  • G6P oxidized to synthesize ATP
  • ATP closes ATP/K channel, high levels of ATP closes channel
  • closing of this channel causes intracellular K to rise, depolarizing the cell 
  • Depolarization causes Ca channel to open causing release of insulin


describe the function of insulin on liver

A image thumb

describe the function of insulin on muscle cells 

A image thumb

describe the function of insulin on adipose

A image thumb

describe function of glucagon

effect is only on liver

  • increases glucose levels by increasing glycogenolysis and gluconeogenesis


explain cell signaling of glucagon

increases cAMP


describe function of somatostatin

  • release stimulated by ingesting food
  • actions:
    • decrease insulin and glucagon secretion
    • decrease GIT motility
    • decrease secretions and absorption by GIT


describe diabetes mellitus (type I)

  • insulin-dependent, juvenile onset
  • caused by destruction of B cells
  • disruption of carbohydrate, lipid and protein metabolism
    • increased levels of glucose, FFAs and AAs in blood
    • increased ketone bodies (DKA)
  • in DKA, H+ ion is exchanged for intracellular K+
  • there is K in ECF which is lost in urine


describe type II diabetes

  • late onset, non-insulin dependent
  • tissues are insulin-resistant due to down regulation of insulin receptors
  • hereditary and obesity are main factors
  • these individuals have sufficient insulin and do not develop ketoacidosis


describe treatments for diabetes

  1. sulfonylurea drugs which stimulate insulin secretion
  2. biguanide drugs (metformin) which up-regulate the insulin receptors