Term
| What causes hyperglycemic, hyperosmolar coma? |
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Definition
-Severe hyperglycemia caused by missed insulin administration or missed diagnosis of diabetes
-in type 2 diabetics, often in the elderly |
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Term
| Explain the pathogenesis of hyperglycemic, hyperosmolar comas. |
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Definition
| Hyperglycemia (from missed insulin dose) acts a strong diuretic --> severe dehydration and loss of electrolytes --> comatose, life-threatening |
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Term
| What is the cause of all complications of diabetes? |
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Definition
| hyperglycemia in uncontrolled or poorly controlled diabetics |
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Term
| What is the major complication associated with hyperglycemia and diabetes? |
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Definition
PROTEIN GLYCATION: aldehyde in glucose spontaneously forms a Schiff base with an amino group in a protein --> diabetic cataracts and atherosclerosis
Other complications: increased DAG and PKC activation --> retinal neuropathy and activation of sorbitol and hexosamine pathways |
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Term
| What can be used as an indicator of how well a diabetic has been controlled over the past few weeks? |
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Definition
| HEMOGLOBIN A1C (formed when glucose reacts with Hg A) |
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Term
| What happens during Phase I of glucose homeostasis? |
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Definition
ORIGIN OF BLOOD GLUCOSE: exogenous
TISSUES USING GLUCOSE: all
MAJOR FUEL OF BRAIN: all |
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Term
| What happens during Phase II of glucose homeostasis? |
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Definition
ORIGIN OF BLOOD GLUCOSE: glycogen and hepatic gluconeogenesis
TISSUES USING GLUCOSE: all except liver; muscle and adipose use at diminished rates
MAJOR FUEL OF BRAIN: glucose |
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Term
| What happens during Phase III of glucose homeostasis? |
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Definition
ORIGIN OF BLOOD GLUCOSE: hepatic gluconeogenesis and glycogen
TISSUES USING GLUCOSE: all except liver; muscle and adipose at even more diminished rates than Phase II
MAJOR FUEL OF BRAIN: glucose |
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Term
| What happens during Phase IV of glucose homeostasis? |
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Definition
ORIGIN OF BLOOD GLUCOSE: gluconeogensis, hepatic and renal
TISSUES USING GLUCOSE: brain, RBCs, renal medulla. small amount by muscle
MAJOR FUEL OF BRAIN: glucose, ketone bodies |
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Term
| What happens during Phase V of glucose homeostasis? |
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Definition
ORIGIN OF BLOOD GLUCOSE: gluconeogenesis, hepatic and renal
TISSUES USING GLUCOSE: brain at a diminished rate, RBCs, renal medulla
MAJOR FUEL OF BRAIN: ketone bodies, glucose |
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Term
| How are pathways regulated and what is the benefit of regulating pathways? |
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Definition
Regulation primarily by:
1. availability of substrates
2. allosteric regulation
3. ATP levels
(also hormonal and long-term adaptation)
regulation limits pairs of opposing pathways so only one can occur at a time |
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Term
| What are the short term regulation effects of insulin? |
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Definition
| decreases cAMP and opposes PKA actions |
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Term
| What are the short term effects of epinephrine and glucagon? |
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Definition
| increase cAMP and activate PKA |
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Term
| What are the long term hormonal regulation effects of insulin? |
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Definition
| uses IRE (insulin response element) to use glucose and store energy as fats |
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Term
| What are the long term hormonal regulation effects of glucago? |
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Definition
| uses CRE (cAMP response element) to increases gluconeogenesis and decrease lipogenesis |
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Term
| What are the long term hormonal regulation effects of fatty acids? |
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Definition
| uses PPRE (Peroxisome Proliferative response element) to increase fatty acid oxidation and ketone body synthesis |
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Term
| What is metabolic syndrome? |
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Definition
-caused by insulin resistance and diabetes
-strongly associated with early atherosclerosis and cardiovascular disease |
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Term
| How is metabolic syndrome different from diabetes? |
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Definition
-In metabolic syndrome, insulin resistance causes greatly elevated plasma insulin but insulin prodcution is adequate to bring down blood glucose to normal range
-contrasted with inadequate insulin in diabetes |
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Term
| How do restricted carbohydrate diets work? |
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Definition
| lead to less production of glycogen in liver and muscle, and less accumulation of fat |
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Term
| How do restricted fat diets work? |
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Definition
| Lead to less storage of TGs in adipocytes, but no affect on glycogen storage |
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Term
| Describe the effects of very low carb diets. |
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Definition
-less than 50g of carbs /day
-have to increase protein so muscles don't waste away, but still reduce total # of calories to lose weight
-gluconeogenesis is active at all times --> increased energy expenditure --> lose weight quicker (but long term effectiveness is about the same as other diets)
-insulin and ketone body production is below normal |
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Term
| What causes Type 2 diabetes? |
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Definition
-progression of insulin resistance
-pancreatic beta islet cell degeneration occurs (from over-exertion)
-some insulin is produced, but less due to beta cell destruction |
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Term
| What is used to treat type 2 diabetes? |
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Definition
-obese patients can respond to diet and weight loss alone
-in early stages, oral anti-diabetic drugs can enhance the action of remaining beta cells
-if not reversed early, beta cell degeneration becomes too great and insulin administration must be used |
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Term
| What causes type 1 diabetes? |
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Definition
autoimmune destruction of all pancreatic beta cells --> no insulin production
-fatal without insulin administration |
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Term
| What percent of diabetics have type 1? |
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Definition
5-10% in north america
1/4 of cases are in children
3/4 are in adults |
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Term
| Why is type 1 diabetes called "starvation amid plenty?" |
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Definition
| because all cells metabolize as if they were in starvation mode, even though the diet supplies adequate fuel |
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Term
| How is type 1 diabetes distinguishable from type 2? |
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Definition
| presence of autoimmune antibodies or lack of insulin c-peptide |
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Term
| What are some of the complications of diabetes? |
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Definition
-peripheral nerve degeneration, microvascular pathology in kidney and retina, and lens shape changes
-severe consequences: kidney failure, blindness, and limb amputation
-all can be reversed or prevented by tightly regulating glucose levels |
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Term
| What do cancer cells use for energy? |
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Definition
-cancer cells use glucose at all times
-they rely on anaerobic glycolysis, which is very inefficient for energy production, but makes them very versatile so they can survive anywhere |
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Term
| What is cachexia and what causes it? |
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Definition
Cachexia: wasting away with fatigue, common in cancer patients
Causes: reduced appetite, increased metabolic demand, high BMR, insulin resistance, and elevated cortisol levels
-TNFa and other cytokines also contribute |
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