Energie Flashcards
(15 cards)
what are the hormones regulating blood glucose and which one decreasesBG?
insulin glucagon epinephrine cortisol GH TH secretin cholecystokinin => only insulin decreases BG
What are the different types of cells of Islet of Langerhans and what do they secrete?
a-cells = glucagon b-cells = insulin D-cells = somatostatin E-cells = grehlin (not in all) F-cells = pancreatic PP
what are the effects of somatostatin?
inhibits glucagon, insulin, PP, increase or decrease neurons signal, inhibits D-cells (-ve feedback) and many GI hormones
what stimulates insulin secretion?
- BG increase
- GI hormones increase
- parasympathetic stimulation
- blood AA increase
what decreases insulin secretion?
sympathetic stimulation
epinephrine
what are the steps of insulin release from B-cells?
- glucose linked to GLUT2 = in cells
- aerobic glycolysis => increases ratio of ATP/ADP
- inhibits K+ channels = blocks K+ efflux
- depolarization of the membrane
- Opening of Ca channels = Ca++ enters b-cells
- exocytosis of insulin in granules
- Opening of K/Ca channels = repolarization
- glucose metabolism = factors facilitate exocytosis and proinsulin synthesis
- GLP-1 = cAMP = increases ion channels + exocytosis
What is the neural anticipation of glucose metabolism?
a slight increase in glucagon to stimulate insulin secretion before glucose is ingested
what are the glucose receptors and where are they situated?
GLUT2 = pancreas b-cells, liver, SI, kidney GLUT3 = brain, placenta, kidney GLUT4 = muscle, heart, adipose tissues, others
how does glucose uptake is regulated by insulin?
insulin = RTK pathway = exocytosis of glut4 receptors
insulin activates glucokinase = glucose into glu 6-p = maintains a low intracellular concentration of glucose = glucose enters
What defects can cause insulin resistance?
- pre-receptor
= autoantibodies against insulin
= mutant insulin - receptors
= decreased # and affinity - post-receptor
= deficient signals
= low glut4 expression
What are the steps leading to T2DM in obese pts?
- visceral fat from adipose tissues accumulation = increases FFAs in circulation
- pro-inflammatory adipokines = inflammation
- FAs into liver = converted into TGs
- tgs utilized by muscles = increased fat into muscles and later myosteatosis
- impaired glu uptake and utilization by mucles
- increased glu in circulation
- dyslipidemia + hyperglycemia
- overstimulation of b-cells (hyperinsulinemia at beginning) and destruction
- T2DM
What are pancreatic polypeptides?
- produced by F-cells of Islet of Langerhans
- decrease appetite
- increased secretion after a meal (by vagus nerve and cholecystokinin)
- inhibit bile acid secretion from blocking gallbladder contraction
- inhibit digestive enzymes
what do GI hormones regulate into the nervous system?
appetite and gut motility
what do GI hormones regulate in pancreas?
insulin or glucagon stimulation
=> postprandial BG
what is the vagus nerve?
the longest nerve of NS
motor and sensory
controls appetite, digestion and metabo
releases acetylcholine = insulin release
