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33 Cards in this Set
- Front
- Back
What is the typical pH in the body?
What MUST it stay between? |
7.4 -> (- log 40nM)
Must be btwn 6.8 - 7.8 to sustain life. |
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What is the ECF concentratino of
-Acid -Sodium |
H+ is 40 nM - nano
Sodium is 150 mM - milli |
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What is the purpose of having acid in the ECF?
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to regulate enzymes and their receptors.
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By what 4 ways is H+ produced in the body?
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1. Co2 rxtn with H2o
2. Anaerobic Glucose metabolism. 3. Fatty acid metabolism 4. Protein metabolism. |
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What acid each process produce?
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Carbon Dioxide = H3O+
Anaerobic Glucose mtbm = Lactic Acid Fatty aa. mtbm = ketone body acids. Protein = HCL/H2SO4 |
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What type of diets produce
-Net base -Net Acid |
Mixed diet -> net Acid.
Vegetarian -> net Base. |
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What 3 process regulate body pH?
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1. Buffers
2. Respiratory system 3. Renal system |
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How fast do buffers respond to pH changes?
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within SECONDS - fast.
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What are the 3 main buffer systems in the body?
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1. Phosphate
2. Proteins (hemoglobin) 3. Bicarbonate system. |
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Which buffer is an open system?
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Bicarbonate - the individual species can be removed/added from the body.
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How soon does the respiratory system respond to pH changes?
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within Minutes.
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How does the respiratory system regulate pH?
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When pH is decreased (more acid), respiration increases in order to decrease CO2, shifting the equilibrium to LEFT and removing H+.
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How soon does the renal system respond to changes in pH?
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within DAYS - slowest.
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How does the renal system respond? (2 major things)
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1. Excretes H+
2. Reabsorbs or creates HCO3- |
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what nephron cells respond mostly to H+ increase? How?
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PCT - prox tubule cells.
-Glutamine breaks into NH4+ and HCO3-. Ammonium gets excreted, Bicarbonate reabsorbed into blood as a buffer. |
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How does Bicarbonate in PCT cells normally get rid of H+?
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1. CO2 diffuses from tubule lumen into PCT cells, Reacts with H2o and forms H2CO3.
2. Carbonic aa. then breaks into Bicarbonate and H+. 3. H+ exchanges for Na+ from lumen, and Bicarbonate is reabsorbed to blood. |
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So how does HCO3- production from Glutamine breakdown help get rid of H+?
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It combines with excess H+ and acts as a buffer.
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Is acid excreted in urine to no end?
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No - the limit is pH of 4.5
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How is acid excretion limited?
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By the phosphate buffer system.
HPO42- filters at glomerulus; forms H2PO4- to prevent hyperacidic urine. |
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What are the 4 terms for disturbed acid-base balance?
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1. Respiratory acidosis
2. Respiratory alkalosis 3. Metabolic acidosis 4. Metabolic alkalosis |
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IF YOU KNOW NOTHING ELSE, WHAT DISTINGUISHES RESP ACIDOSIS?
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High Co2 levels.
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What disease causes respiratory acidosis?
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Decreased ventilation from severe asthma (results in high CO2 levels)
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How does the patient compensate for respiratory acidosis?
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With the renal system, by producing HCo3- to buffer:
-More H+ secretion -More HCO3- reaborption |
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What is the primary cause of Respiratory alkalosis?
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Decreased CO2 levels, due to -high altitudes
-increased ventilation. |
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How is respiratory alkalosis compensated for?
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With the renal system;
-Less H+ secretion -Less HCO3- reabsorption. |
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What's the disadvantage of how respiratory acidosis/alkalosis are compensated?
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It takes days so you feel bad for a few days before getting better.
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What is metabolic acidosis ALWAYS ASSOCIATED WITH?
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Decreased HCO3- due to
-Loss of HCO3- OR -Addition of H+ |
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What are 3 causes metabolic acidosis?
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1. Kidney failure (no HCO3- reabsorption)
2. Diarrhea (lose alk fluid) 3. Exercise (lactic acid) |
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How does the body compensate for metabolic acidosis?
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By breathing more - fast response w/in minutes.
Incr. ventilation decreases CO2 and H+. |
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What is the main problem in metabolic alkalosis?
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High HCO3- or loss of H+.
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What are 2 causes of metabolic alkalosis?
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1. Antacid abuse
2. Vomiting |
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how does the body compensate for metabolic alkalosis?
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by less respiration - decresaed ventilation increases CO2 and H+.
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How do you distinguish in all these cases?
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by measuring Co2 and HCO3- levels,NOT PH.
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