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26 Cards in this Set
- Front
- Back
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what is glucose
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simple monosaccaride
universal fuel used by all organisms |
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why is glucose important
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without glucose most all organisms would not be able to exist as they do including humans
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why is glucose essential nutrient
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humans must maintain glucose levels to survive but too high levels are toxic
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what is the RDA of glucose
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130 grams/day
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what tissues or cells can only use glucose as their only source of energy
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RBC
WBC Renal Medulla Retina Cornea Lens Peripheral Nerves Testis Sperm cells *Glucose is critical for pancreatic beta cells and bran but not obligate for these tissues |
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how much glucose does the brain use per day?
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120 grams/day
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What are the three sources of glucose?
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Intestinal absorption from food
Glycogen breakdown Gluconeogenesis Only the liver and kidney release glucose into the bloodstream |
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Where is glycogen stored at? How much energy is stored in its reserve? how does diet & activity affect these reserves?
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Glycogen: LIver & Muscle
Liver: 70 kg, ~280kcal Muscle: 120 g, 480kcal |
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Where is glucose stored at? How much energy is stored in its reserve? how does diet & activity affect these reserves?
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glucose: body fluids
Fluids: 20 g ~80 Kcal |
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Where is fat stored at? How much energy is stored in its reserve? how does diet & activity affect these reserves?
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Adipose tissue
15,000 g 135,000 Kcal |
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Where is protein stored at? How much energy is stored in its reserve? how does diet & activity affect these reserves?
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Muscle
6,000 g 24,000 Kcal |
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what 4 tissues take up the most glucose after a meal?
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Liver
Adipose Skeletal muscle Brain |
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what organ has the greatest glucose uptake after a meal? what does the tissue do with the glucose that it takes up?
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Liver is the organ that takes up the greatest amount of glucose (2/3)
Forms glycogen stores, cholesterol, & fatty acids stores & synthesis, glucuronic acid formation for detox |
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Rank the other tissues besides the liver that take up glucose and describe what the tissue does with the glucose?
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2. Adipose tissue: converts to fatty acids
3. Skeletal muscle: primarily forms glycogen sotres 4. Brain: doesn't form energy stores, typically glucose immediately used |
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what controls GLUT-4 levels in the cell membrane of skeletal muscle?
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Insulin: causes temporary movement of GLUT-4 to cell surface that persists only as long as the insulin spike does
Exercise: activates cyclic-AMP dependent kinase that persists longer (up to 48 hrs) than insulin to move GLUT-4 to cell surfaces |
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How do we get glucose into cells?
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1. Insulin-Sensitive: Facilitated transport of GLUT-4
2. Insulin-insensitive: Active transport: Na/Glucose pumps (6 different types SGLT-2,3 only move glucose) facilitated transport: Glut-3, Glut-1, Glut-2 Liver uses Glut-2 since Glut-2 only takes up glucose when in high concentration Neurons use Glut-3 since they require high levels of glucose at all times |
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what glucose transporter do neurons use?
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Glut-3
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what glucose transporter does the LIver use?
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Glut-2
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why is it important to control the blood glucose concentration and how is the amount of glucose in human blood controlled?
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Importance: If too how, brain may die, If too high, glucose is toxic and tissue damage occurs
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What is HYPOglycemia?
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Hypoglycemia is too LOW of blood sugar
blood sugar < 60 mg/dl (symptoms start) Signs & Symptoms: altered mental status, restlessness, impatience, hunger, anger/rage, bizarre behavior, excessive sweating, tachycardia, seizure, coma Treatments: check and confirm blood glucose, consume high glycemic index foods, recheck every 15 minutes |
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What is Hyperglycemia?
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Too HIGH blood glucose
Either Type 1 or 2 diabetics can develop Ketoacidosis but usually only type 2 will develop Hyperosmolar Coma Causes: Blood glucose > 240 mg/dl T1D: failure to take insulin T2D: Cells don't respond to insulin Common Causes: Infection, UTI, Pneumonia, Burns, Peritoneal Dialysis Signs/Symptoms: Hunger, blurred vision, nausea, dry skin, drowsy, extreme thirst, frequent urination Treatment: fluid replacement, insulin, electrolyte replacement, find the cause |
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what happens in the first stage of glucose processing?
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peak 1 hour after meal
Exogenous origin of blood glucose All tissues are using glucose major fuel for the brain is glucose |
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2nd stage of glucose processing
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starts 2-3 hours post meal
Origin of blood glucose: Glycogen & Hepatic Gluconeogenesis Tissues using glucose: all tissues except liver, muscle, adipose rates are slow Major fuel for the brain is Glucose |
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Phase 3 of glucose processing
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Starts: 12-16 hours post meal
Origin of Blood glucose: Hepatic gluconeogenesis & glycogen Tissues using glucose: all except liver, muscle, adipose intermediate rates between 2 & 4 Major fuel for the brain: Glucose |
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Phase 4 of Glucose processing
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2-4 days NO food intake
Origin of blood glucose: Hepatic & Renal Gluconeogenesis Tissues using Glucose: Brain, RBC, Renal Medulla, Small amount by muscle Major fuel for the brain: Glucose & Ketone Body |
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Phase 5 of Glucose processing
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2 weeks NO food intake
Origin of Blood Glucose: Hepatic & Renal Gluconeogenesis Tissues using Glucose: RBC and Renal Medulla/Brain rate slows Major fuel for brain: Ketone body (70%) & Glucose |
