Term
| Explain how pathways operate at various levels of activity. |
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Definition
-Most pathways can occur in all cells
-Not all cells use all pathways at the same time
-At any one time, pathway function can vary dramatically across tissues |
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Term
| What causes pathway flux variation? |
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Definition
-Variable inputs and variable outputs
-All living animals must evolve to tolerate variability in life |
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Term
| How does leptin play a role in insuling resistance? |
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Definition
| Satiety sensing depends on leptin, but leptin is made in white fat adipocytes, so it's highly elevated in obese people --> suggests that obese have leptin resistance |
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Term
| Why does long term dieting not work? |
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Definition
| Long term starvation decreases T3 which decreases basal metabolic rate and thus makes caloric restriction less effective |
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Term
| What are the causes of Kwashiorkor protein malnutrition? |
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Definition
-diet adequate in calories but inadequate in protein
-most common in children and infants due to their higher need for protein for growth and development |
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Term
| What are the symptoms of Kwashiorkor? Can it be treated? |
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Definition
-poor growth, low plasma protein and amino acid levels, muscle wasting, edema, diarrhea, increased susceptibility to infection -with treatment some, but not all, fully recover and develop
-subcutaneous fat, increased insulin, enlarged and/or fatty liver, all tissues can't synthesize proteins (decreased A.A. metabolism)
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Term
| What are the causes of Marasmus? |
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Definition
Marasmus is a form of starvation; it is most often seen in war zones and poor-developing countries. Often seen in infants due to early breast-milk weening, but can be second to chronic diarrhea or malabsorption syndromes
Not common in developing countries - but can be second to dementia, strokes, or throat/esophageal cancer in elderly |
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Term
| What are the symptoms of Kwashiorkor not found in Marasmus patients? |
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Definition
Found in Kwashiorkor (but not Marasmus):
subcutaneous fat, increased insulin, enlarged and/or fatty liver |
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Term
| What are the four stages of the starve-feed cycle? |
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Definition
1. well-fed state
2. early fasting state
3. fasting state
4. early re-fed state |
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Term
| Describe the well-fed state |
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Definition
-Diet supplies all needs
-stored fuels are only made in this state |
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Term
| Describe the early fasting state |
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Definition
-when dietary nutrients become inadequate
-glycogen begins to be used in this state |
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Term
| Describe the fasting state |
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Definition
-A.A. metabolism and lipolysis must supplement the cori and alanine cycles
-other fuels begin to be used in this state |
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Term
| Describe the early re-fed state |
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Definition
-The liver relies on gluconeogenesis for glycogensis
-uses lactate and alanine to make G6PD --> glycogen
-somewhat similar to the early-fasting state, except that instead of releasing glucose into the blood, the glucose produced during gluconeogenesis is used to make glycogen
Early re-fed: glycogen is MADE and used
early-fasting: glycogen is used from the glycogen stores
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Term
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Definition
-During fasting, liver cell mitochondria are essential for gluconeogenesis and for urea synthesis. If they are damaged then the ability to survive during fasting is impaired
-Reyes is caused by aspirin treatment of children with viral infections, and is sudden and life-threatening (aspirin is toxic)
-warning label has decreased # of cases of Reyes |
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