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5 Cards in this Set
- Front
- Back
Recognize the mechanisms that maintain amino acid concentration in blood |
Dietary proteins digested; AAs absorbed
Endogenous protein degraded; AAs released - skeletal muscle
De novo synthesis of AAs from TCA intermediates |
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Define how amino acids contribute to the nervous system |
Nervous system - BCAAs & NH₄⁺ (as NH₃) cross blood brain barrier - BCAAs transaminate α-KG to glutamate - Glutamine synthase creates glutamine from NH₄⁺ and glutamate - glutamine is shuttle to neuros where it can be converted back to glutamate - translocation of glutamate as glutamine prevents excitotoxicity |
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Define how amino acids contribute to the liver |
Glucagon promotes AA degradation in liver
NH₄⁺ can enter urea cycle
Carbon skeletons can be used for gluconeogenesis |
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Identify the roles of glutamine in the blood |
Glutamate is one of two nitrogen transporters in blood
It is aminated (addition of NH₄⁺) to form glutamine which then travels through the blood - often heads to liver where NH₄⁺ can be donated to urea cycle |
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Define negative nitrogen balance and explain why it is physiologically relevant |
More NH₄⁺ is excreted in the urine than is maintained in the blood
Often occurs during hypercatabolic states brought on by - trauma - surgery - burns - sepsis
Epi and glucocorticoids lead to increased AA metabolism in the liver and skeletal muscle |