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23 Cards in this Set
- Front
- Back
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Is pancreas endocrine or exocrine gland?
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Both. Exocrine part secretes digestive hormones and endocrine part (islets of Langerhans) secrete insulin, glucagon, and somatostatin.
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What hormones are secreted by endocrine pancreas?
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Insulin (beta cells), glucagon (alpha cells), somatostatin (delta cells).
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What is the major regulatory factor for insulin secretion from endocrine pancreas?
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Plasma glucose concentration
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How does glucose enter the β-cell?
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Glucose enters the beta cell via the GLUT 2 transporter. It is then phosphorylated and begins a cascade which ends in the Calcium-mediated exocytosis of insulin.
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Is this insulin-dependent transport?
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No! GLUT 2 transporter is insulin-independent transport. GLUT 4 is insulin-dependent.
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What are the abnormalities in plasma glucose regulation for patient with hyperglycemia and high C peptide concentration?
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A high C peptide concentration indicates that abundant insulin is being made. Thus, the problem is not with the Beta cells but with the target cells.
Growth hormone induces insulin resistance and causes hyperinsulinemia with concurrent hyperglycemia. |
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How does plasma insulin level change in response to a meal?
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Plasma insulin will increase in response to a meal due to increased plasma glucose levels.
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Is insulin receptor G-protein coupled receptor?
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No. Insulin receptors are tyrosine-kinase linked receptors.
Tyrosine kinase receptors have intrinsic enzymatic activity, instead of activating another enzyme. |
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Where is insulin receptor located (on the plasma membrane or in cytoplasm)?
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The insulin receptor is located on the cell membrane. Insulin is a peptide hormone, and with most peptide hormones, they do not enter the cell but instead bind to a surface receptor.
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In what tissues insulin stimulates glucose uptake?
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Skeletal muscle, cardiac muscle, and adipose tissue.
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What is the effect of insulin on plasma free fatty acids?
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Insulin enhances transport and utilization of plasma free fatty acids.
Thus, it would decrease the amount of FFA in serum. |
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What is the effect of insulin on fat tissue triglycerides?
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Insulin promotes fat synthesis.
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Does insulin stimulate glycogenolysis?
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No. It inhibits glycogenolysis.
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Does insulin stimulate glycolysis?
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Yes, insulin activates glycolysis.
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Does insulin stimulate gluconeogenesis?
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No, insulin inhibits gluconeogenesis. If you have a lot of glucose, you don't want to waste energy making more.
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Does glucagon stimulate glycogenolysis?
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Yes, glucagon stimulates the breakdown of glycogen in order to release more glucose into the bloodstream (from the liver).
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Why insulin is anabolic hormone?
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Because it stimulates the synthesis of protein and fat.
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Why insulin is also known as “growth factor”?
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Because its expression is increased by increased levels of growth hormone.
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What are major actions of glucagon?
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Glucagon increases the levels of plasma glucose, free fatty acids, and keto acids.
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Does glucagon stimulate gluconeogenesis?
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Yes, glucagon stimulates gluconeogenesis in the liver to increase the amount of free glucose available for cellular uptake.
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What are major signals for glucagon release?
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Sympathetic stimulation via beta-adrenergic receptors, low plasma glucose, high AA, stress, fasting, exercise.
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Why is regular physical activity recommended for patients with diabetes mellitus?
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Because exercise increases the uptake of glucose in skeletal muscle, thereby contributing to lower high glucose levels.
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What hormones increase plasma glucose level?
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Glucagon, cortisol, norepinephrine, epinephrine.
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