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97 Cards in this Set
- Front
- Back
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What is the Primary determinant for the secretion of insulin and glucagon?
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Level of glucose in the blood
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During exercise (glucagon or insulin) is increased?
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Glucagon increased; Insulin is decreased
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What happens to the insulin-sensitivity of muscle cells during exercise?
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It increases by an uknown mechanism (allowing glucose to enter the insulin-dependent tissue)
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During a carbohydrate meal (glucagon or insulin) is increased?
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Insulin
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What are the normal flucuations of glucose (mg/dL) in the body?
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60 - 160 during fasted and fed states
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Below what level of glucose (mg/dL) will symptoms of hypoglycemia occur?
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50
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In the postprandial period, what DIRECTLY stimulates the release and biosynthesis of insulin?
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Glucose (rapidly taken up by the intestines)
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Gastric inhibitory polypeptide and similar enteric factors do what to insulin release?
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Increase insulin release (act as secretagouges for insulin)
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What organ extracts nearly 50% of the glucose following a meal?
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Liver
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How much glucose (per hour) does the human brain require?
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6 grams
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This hormone primarily prevents HYPER glycemia?
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insulin
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What does glucagon prevent (hypoglycemia or hyperglycemia)?
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hypoglycemia
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Hepatic glycogenolysis occurs when the insulin:glucagon ration (increases or decreases)?
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Decreases (rising glucagon)
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(glucagon or Insulin) promotes gluconeogenesis and ketogenesis?
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Glucagon
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What does the CNS use as an alternative fuel source; as this fuel's concentration rises following a declining insulin:glucagon ratio?
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Ketones
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The fact that the CNS uses ketones is important for sparring what other source of fuel?
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Protein (prolongs survival; every protein is functional)
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What causes "stress hyperglycemia"?
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rise in glucagon following serious injury or shock
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What does our body primarily store energy as?
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Adipose tissue fat (and liver/muscle glycogen)
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Why is glycogen an inefficient form of energy storage?
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Water (each gram of glycogen requires 1-2 grams of water)
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Which energy store (fat or glycogen) is more rapidly accesible?
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Glycogen
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Which cells of the pancreas secrete insulin?
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A-cells
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Which cells of the pancreas secrete Somatostatin?
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D-cells
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Insulin causes (lipogenesis or lipolysis)?
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Lipogenesis
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TRUE/False Somatostatin coordinates the function of both insulin and glucagon?
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TRUE;
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All of the actions of somatostatin are (stimulatory or inhibitory)?
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Inhibitory
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Conversion of pro-insulin into insulin occurs in what organelle?
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Golgi
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What is the half-life of insulin?
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8-10 mins
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What does glutathione transhydrogenase do?
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degrades insulin in the liver and kidney
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Does insulin cross the placenta?
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No
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What kind of receptor is the insulin receptor?
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tyrosine kinase (autophosphorylates)
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TRUE/FALSE cAMP is a second messenger for insulin action?
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FALSE; insulin actually lowers cAMP
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TRUE/FALSE the biologic action of insulin requires a high percentage of binding to the insulin receptors?
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FALSE; only a small percentage
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How does a cell increase it sensitivity to insulin or any other hormone?
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Producing more receptors; Affinity can also be modified
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The numbers of insulin receptors are reduced in the case of (hyperinsulinemia or hypoinsulinemia)?
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Hyperinsulinemia (they are down-regulated)
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Trained athletes will normally have a(n) (reduced or increased) insulin sensitivity?
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Increased
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Glucocorticoid deficient patients (such as adrenalectomy) will have an insulin (hypersensitivity or hyposensitivity)?
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Hypersensitivity
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What process in the cell constitutes the "off-switch" for insulin action?
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internalization of the insulin receptors (along with insulin….maybe a soirce for intacellular insulin action?)
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How does insulin stimulate glucose trapping in the liver?
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Activates glucokinase
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Insulin (increases or decreases) glycogen phosphorylase activity?
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Decreases
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Insulin (increases or decreases) the formation of alpha-glycerophosphate in adipose?
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Increases (glucose is taken up and metabolized to this product to provide the backbone for triglyceride storage)
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Insulin activates (hormone sensitive lipase OR hormone sensitive lipoprotein lipase)?
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Hormone sensitive lipoprotien lipase
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Insulin promotes (release or storage) of protein?
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Storage
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Insulin (inhibits or stimulates) malonyl-coA?
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Stimulates (malonyl-CoA inhibits the transport of fatty acids into the mitochondria where B-oxidation occurs)
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TRUE or FALSE Both insulin and glucagon circulate free in the plasma?
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TRUE;
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Which organ does glucagon have a greater effect on (muscle or liver)?
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Liver
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Type 1 Diabetics have (no insulin or have insulin resistance)?
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NO insulin
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Why does glucagon excacerbate Type 1 diabetics?
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A-cells are insulin-dependent and without insulin there is NO inhibition of glucagon; glucagon increases and releases even more glucose into the blood promoting hyperglycemia
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How can gestational diabetes be explained?
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Insulin inhibition by placental hormones AND placental degradation of insulin
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What are the five MAJOR classifications of diabetes?
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Spontaneous diabetes which is insulin-dependent or insulin-independent; secondary diabetes; impaired glucose tolerance; gestational diabetes
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Excess secretion of contra-insulin hormones from these diseases may result in secondary diabetes?
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acromegaly, cushings, and pheochromocytoma
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People with impaired glucose tolerance have a 20hr value on glucose tolerance between what levels?
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140 and 200 mg/dL
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How is the diagnosis of diabetes mellitus established (what diagnostic tools)?
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Fasting hyperglycemia; diagnostic oral glucose tolerance test; elevated levels of glycated hemoglobin
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Which type of diabetes has a 40-50 % concordance rate in monozygotic twins?
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Type 1 diabetes (insulin dependent)
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What is the underlying basis for the insulin resistance of Type 2 diabetes which is caused by obesity?
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chronic, low-grade, systemic inflammation (mediated by macrophages and cytokines)
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What two cytokines mediate the inflammation from obesity which is responsible for type 2 diabetes?
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TNF-a and MCP-1 (signals monocytes to enter adipocytes and transoform into macrophages)
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What therapeutic tool provides the first approach to diabetic management?
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Diet (manage food intake)
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What are the overall objectives in dietary therapy?
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achieving normoglycemia and ideal body weight
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What percent of calories should comprise of carbohydrates?
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50-60%
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What is the single most effective way to manage an obese diabetic?
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Achieve IDEAL WEIGHT
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What meal of the day is added to the treatment of INSULIN-DEPENDENT diabetics?
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Bedtime meal to avoid nightime hypoglycemia
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What does exercise promote which is beneficial in treating hyperglycemia?
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Glucose utilization
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What are sulfonylureas?
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Orally active hyperglycemic drugs (increase insulin secretion; decrease hepatic glucose output; increase peripheral uptake of glucose)
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What process involving proteins appears to be the major factor causing many of the degenerative changes associated with chronic hyperglycemia (high blood glucose)?
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abnormal glycation
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TRUE/FALSE Glycation is enzyme-dependent?
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FALSE;
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What sugar accumulates in diabetics as a result of over-activation of aldose reductase (by increased substrate)?
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Sorbitol
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Basement membrane thickening as a result of glycoprotein accumulation is what type of angiopathy (microangiopathy or macroangiopathy)
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microangiopathy
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What are the clinical manifestations of microangiopathy that occur in diabetics?
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retinopathy; nephropathy with hypertension; renal failure; neuropathy
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What is one of the leading causes of blindness in the US and England?
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Diabetic retinopathy
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This type of retinopathy (nonproliferative or malignant) is composed of microaneurysms, mild retinal hemorrhages; and exudates?
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Non-proliferative
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Which type of retinopathy (non-proliferative or malignant) has a 50% risk of blindness?
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Malignant
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This angiopathy (micro or macro) can lead to angina or myocardial infarcation, gangrene, and cerebral infarcation?
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Macroangiopathy
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This diabetic complication results in 10-12% of all deaths in diabetics and includes lesions of glomerulosclerosis, pyelonephritis, and necrotizing papillitis?
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Diabetic nephropathy
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Symmetric loss of sensory in distal extremities is seen in this complication of diabetes?
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Peripheral neuropathy
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What occurs when the renal threshold for glucose is exceeded by the renal glucose load?
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Glucosuria
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What is the rate determining factor for the amount of ketogenic substrate the liver recieves?
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Hormone sensitive lipase (normally inhibited by insulin)
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What is the rate limiting step for the transfer of free fatty acids from the cytosol into the mitochondria in the liver?
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CPT1 (normally inhibited by malonyl coA, which is high under high insulin)
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What two lipid metabolism steps become unregulated in diabetic ketoacidosis due to insulin deficiency?
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Hormone sensitive lipase and CPT1
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What organ is solely responsible for producign the ketoacids?
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liver
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What are the three acids produced by ketogenesis and which is neutral?
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acetoacetate; B-hyrdroxybutyrate; and acetone (neutral)
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What happens to the fluid of the intracellular compartment during diabetic ketoacidosis?
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The EFFLUX out because of osmotically active glucose (increase in extracellular fluid)
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What happens to water conservation during ketoacidosis?
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it is lost because of osmotically active glucose (osmotic diuresis)
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TRUE/FALSE Electrolytes are lost during diabeetic ketoacidosis?
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TRUE; (due to ketoacids spilling over into the urine….charged molecules)
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Blood serum in ketoacidodic patients will be (hypotonic or hypertonic)?
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Hypertonic
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What is the most immediate treatment for diabetic ketoacidosis?
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Fluid replacement (to lower blood glucose by increasing renal function)
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What occurs to intracellular potassium during a ketoacidodic attack?
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Attempts at buffering H+ ions by shuttling them in result in movement of K+ out extracellularly and this causes loss of K+ (can be dangerous if hypokalemic)
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Glucagon primarily induces (anabolism or catabolism)?
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Catabolism
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What are the 5 counter-regulatory hormones to insulin?
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glucagon, norepinephrine, epinephrine, cortisol, growth hormone
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These counter-regulatory hormones provide immediete protection against hypoglycemia?
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glucagon and the catecholamines
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The catecholamines (epinephrine and norepinephrine) do what to glucose metabolism?
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increase production of glucose and decrease (resting muscle) utilization of glucose by muscle
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Catecholamines activate what process in the adipocytes (lipogenesis or lipolysis)?
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lipolysis (via hormone sensitive lipases)
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What are the actions of catecholamine on the pancreatic islets?
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increase glucagon and decrease insulin
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These counter-regulatory hormones provide a long term adaptation to reduced food intake?
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cortisol and growth hormone
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Cortisol and growth hormone result in the (up-regulation or down-regulation) of insulin receptors?
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Down-regulation ("insulin resistance")
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TRUE/FALSE Cortisol inhibits the actions of insulin on BOTH glucose production AND glucose utilization?
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TRUE (increases gluconeogenesis AND decreases insulin sensitivity in cells)
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What fuel is the end-goal (which fuel in the body is preffered) while cortisol and growth hormone are being secreted under long-term stress?
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FAT
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TRUE/FALSE There are backup mechanisms in place to protect the body against hyperglycemia in case of insulin deprivation?
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FALSE; diabetes type 1
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Parasympathetic stimulation via AcH will (inhibit or stimulate) insulin secretion?
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Stimulate (sympathetics stimulate glucagon)
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