Fichas
Acid Base Balance.
Fichas del conjunto (17)
- 1How is Hydrogen ion concentration calculated. Define Acidosois and Alkalosis.pH = -log [H+]
*ACIDOSOIS - pH < 7.4
*ALKALOSIS - pH > 7.4 - 2List sources of H+gains.*Hypoventilation (excessive retention of CO2)
*Production of nonvolatile acids e.g metabolism of proteins
*Gain of H+ due to loss of bicarbonate (HCO3-) in diarrhea and other non gastric fluids
*Gain of H+ due to loss of HCO3- in urine - 3List sources of H+ losses.*Utilization of H+ in the metabolism of organic anions
*Loss of H+ in vomit – acidic stomach
*Loss of H+ in urine
*Hyperventilation (excessive loss of CO2) - 4What is carbonic anhydrase?Enzyme = Expressed in a range of tissues including lung, kidney, eyes, intestine and red blood cells (erythrocytes)
- 5Explain the transport of c02 in blood.
- 6Explain how total blood co2 is calculated.Total-blood CO2= dissolved CO2, HCO3- and HbCO2
- 7Explain transport of c02 in the lungs.
- 8What happens to the hydrogen ions generated when co2 is transported.*Co2 generated in the tissue.
*Oxyhaemoglobin dissociates and oxygen is taken up by the cell
*The carbon dioxide released dissolves with water to form bicarbonate and hydrogen ions
*High affinity for hydrogen ions so bind quickly to haemoglobin . - 9What happens during hypoventilation?*HYPOVENTILATE (breathing at a decreased rate e.g. emphysema) and prevents the normal elimination of CO2
*Arterial PCO2 and H+ concentration would increase
= RESPIRATORY ACIDOSIS - 10What happens during hyperventilation?*HYPERVENTILATE (breathing at a increased rate)
*Lower Arterial PCO2 and H+ concentration
= RESPIRATORY ALKALOSIS. - 11Explain the control of ventilation.
- 12Explain how the kidney controls H+ concentration*Kidneys can regulate H+ concentration by altering plasma HCO3- levels. Amount of bicarbonate
*ACIDOSIS = Kidneys do not excrete bicarbonate and start to generate new bicarbonate
*ALKALOSIS = Kidneys respond by excreting large amounts of bicarbonate ions - 13Explain regulation of bicarbonate in the kidneys.*Bicarbonate is completely filtered at the renal corpuscles and significant amounts are absorbed in the proximal collecting duct, loop of henle and cortical collecting duct
*Collecting duct can also secrete HCO3-
*HCO3- filtered by kidneys + HCO3- secreted – HCO3- reabsorbed = renal HCO3- excretion - 14What are the two main categories of renal carbonic anhydrases?INTRACELLULAR = in cytosol) e.g. red blood cell and kidney epithelial cells lining tubules – all lined with epithelial cells e.g. collecting duct
EXTRACELLULAR = e.g. found in the brush boarder surface of epithelial cells in kidney - 15What happens when all filtered bicarbonate has been reabsorbed?Additional buffering can be gained with “new” bicarbonate ions, synthesized in the tubule cells, as long as a “sink” for hydrogen ions is available.
= NET GAIN HCO3-
*Additional “new” bicarbonate ions are synthesised from catalysis of the amino acid glutamine. - 16Explain the response to acidosis at the kidney.*Sufficient H+ is secreted to reabsorb all the filtered HCO3-
*More H+ is secreted and adds new HCO3- in the plasma due to non-bicarbonate urinary buffers
*Tubular glutamate metabolism and ammonium secretion are increase and adds new bicarbonate to the plasma
*Net result: More new HCO3- added to blood and plasma bicarbonate is increased = compensates for acidosis
=Urine is highly acidic (pH 4.4) - 17Explain the response to alkalosis at the kidney.*Amount of H+ secretion is not enough to reabsorb all the filtered bicarbonate so this is excreted in urine
*Little or no excretion of H+ on nonbicarbonate buffers
*Decreased Tubular glutamate metabolism and ammonium excretion
*Net result: Plasma bicarbonate is decreased and compensates for alkalosis
=Urine is alkaline (pH >7.4)
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- (10) Respiratory System and Cellular Respiration) Pharmacy Fichas sobre Acid Base Balance., creado por Yasmin Beer el 06/04/2018.
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- Yasmin Beer
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