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22 Cards in this Set
- Front
- Back
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What are the endocrine cells in the pancreas?
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The Islet cells: alpha, beta, and delta cells
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What do the alpha cells produce in the pancreas?
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Glucagone - like peptides
Glucagon Proglucagon |
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What do the beta cells of the pancreas produce?
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Insulin, proinsulin, C-peptide, and amylin
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What do the delta cells of the pancreas produce?
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Somatostatin
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Describe insulin in regards of its makeup and precursors
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Produced from proinsulin which has an alpha and beta chain that are linked by a C-peptide.
When proinsulin is converted to insulin the C-peptide is removed and S-S are formed between the Alpha and Beta |
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What stimulates the release of insulin?
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Glucose is most obvious
Amino acids, Glucagon, |
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What inhibits the release of insulin?
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Alpha-adrenergic stimulation and somatostatin
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What happens when you have increased glucose?
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You will have an increase in the ATP/ADP ratio which inhibits an ATP-sensitive K+ channel.
Inhibition of this ATP-Sensitive K+ channel causes depolarization of the cell and activates a voltage gated Ca2+ channel |
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So, what does an increased intracellular [Ca2+] signal
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Release of insulin
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Describe the incretin effect
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when you give oral insulin as opposed to injected Insulin you have a better effect.
Incretins are hormones produced by the GIT GIT releases incretins when you administer oral insulin, so you get a much > response from the Beta cells to the release of insulin. |
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What is GLUT4
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insulin sensitive glucose transporter on plasma membrane of muscle cells
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Where is the insulin receptor and what is it composed of
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found on the membrane and has an alpha and beta chain subunit.
Beta unit shows tyrosine kinase activity |
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What effect does insulin have on the liver?
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promotes storage of glucose = glycogen synthesis.
promotes Storage of fatty acids = triglyceride production promotes protein synthesis decreases: gluconeogenesis and glycogenolysis |
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What effect does insulin have on the adipose tissue?
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promotes: glucose uptake via GLUT4, increased conversion of glucose to trigs, and uptake of F.A's
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What effect does insulin have on muscle?
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Increases glucose uptake via GLUT4,
Stimulates glucogen production. Stimulates protein synthesis |
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Describe glucagon
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Peptide hormone
produced from proglucagon Proglucagon breakdown yeilds glucagone + peptides |
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What causes the secretion of glucagon?
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Hypoglycemia & Amino Acids
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What inhibits Glucagon?
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Hyperglycemia & Somatostatin
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What is the primary target for glucagon?
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Liver: where it stimulates:
- gluconeogenesis -glycogenolysis -lipolysis Inhibits glycolysis |
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What is the glucagon receptor?
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G-alpha-s
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What stimulates secretion of somatostatin?
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Glucose, arginine, and GI hormones
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Effects of Somatostatin?
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Slows gastric emptying
Decreases gastric secretions inhibits insulin and glucagon secretion |
