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Does acid have more or less ions?
More H+ ions
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Does base have more or less ions?
Fewer H+ ions in a solution that can accept H+ ions
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Why is acid-base balance important?
- Cell membrane integrity
- Cellular enzymatic speed
- Speed at which interactions in body happen
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Where do acids come from ?
- Metabolic processes
- NOrmal by-product of nutrient absorption and metabolism
- Buffered by body systems
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Where do bases come from?
- chemicals that can donate or accept H+ ions
- Bicarb is the base used to counteract acidosis
- production of bicarb occurs in the kidneys
- bicarb is produced in response to an acid-base imbalance
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What is a buffering system?
- absorbs or releases H+ ions to correct imbalances in acid-base balance
- regulates H+ ion concentration by maintaining ration of 20 parts bicarb to one part carbonic acid
- this concentration is measured by the PH level
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What is arterial pH?
- Indirectly measure H+ ions
- H+ ion =>acid=<pH
- H+ ion =<acid >alkaline=>pH
- reflects the balance between CO2 and HCO3
- Above 7.45 = alkaline (alkalosis)
- Below 7.35 =Acid (acidosis)
- Normal between 7.35-7.45
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Where does bicarb come from?
kidneys
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Where does CO2 come from ?
Lungs
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What are acid-base regulators?
Chemical, biological, physiological
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Explain chemical regulation
Carbonic acid is first to react, happens in seconds
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Explain biological regulation
- Hydrogen ions absorbed & released by cells
- after chemical buffering
- slow process
- must exchange with another + ion or be accompanied by ions of opposite charge
- K+
- Hemoglobin-oxyhemoglobin system
- Chloride shift
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Explain physiological regulation
- Kidneys
- regulation takes hours to days to occur
- reabsorbs bicarb when acidosis occurs
- excretes bicarb when alkaloisis occurs
- also uses PO4 ion to form phosphoric acid to excrete H+ ions
- Use another mechanism, the ammonia mechanism to regulate balance
- Amino acids in renal tubules
- Ammonia + H+ =(ammonium) = excreted through urine
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Explain physiological regulation in regard to lungs
- Lungs
- response within minutes
- increased H+ and CO2 = increased respirations
- metabolic acicosis = >respirations = more CO2 excreted through exhalantion=< acidosis
- Metabolic alkalosis=<respirations = more CO2 retained =>acid
- CO2 + H2O <> H2CO3 carbonic acid
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What is a normal pH?
7.35-7.45
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What is a normal PaCO2 (partial pressure depth of ventilation)?
35-45 mmHg
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What is a normal PaO2?
80-95 mmHg
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What is a normal O2 saturation?
95-99%
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What is normal base excess?
+/- 2
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What is normal HCo3?
22-26 mEq/L
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What do kidneys do for acid/base buffer?
Excrete to obtain buffer for extracellular fluid
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Hyperventilation with PaCO2
Below 35 mmHg
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Hypoventilation with PaCO2
increased 45 mmHg
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Explain respiratory acidosis and when it occurs
H2CO3 excess, During hypoventilation, pH is decreased, CO2 is increased, Carbonic acid is increased
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Explain respiratory alkalosis and when it occurs
Hyperventilation, asthma, anxiety, Increased pH, PaCO2 decreased, CO2 decreased, H2CO3 deficit
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Explain metabolic acidosis and when it occurs
Decreased bicarb, happens if too much diarrhea or renal disease,reversed by lungs, HCO2 deficit
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Explain metabolic alkalosis and when it occurs
Increased bicarb, HCO3 excess, due to vomiting, too much GI suctioning, K+ deficiency
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What happens if you have too much CO2?
Acidosis occurs
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What if you have not enough CO2?
Alkalosis occurs
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what happens if you hyperventilate?
Alkalosis occurs
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What happens if you have hypoventilation?
Acidosis occurs
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When does acid-base balance occur?
When acid/base excretion=acid/base production
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What does acid/base balance do?
Maintains cellular integrity, speeds up cellular enzymatic processes
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What is acid/base regulated by
Chemical, biological and physiological processes
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What is the first line of defense for regulation?
The chemical buffering system
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what two organs does regulation happen through?
biologic and physiologic of lungs and kidneys
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What happens if you have increased HCO3 if it is above 26?
Alkalosis (kidneys)
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What happens if you have decreased HCO3 if it is below 22?
Acidosis (kidneys)
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What happens if you have increased PCO2 above 45?
Acidosis (lungs)
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What happens if you have decreased PCO2 if it is below 35?
Alkalosis (lungs)
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If there are changes in the kidneys what process is it?
Metabolic
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If there are changes in the lungs what process is it?
Respiratory
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If the pH and HCO3 are going in the same direction what process is it?
Metaboic (kidneys)
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If pH and CO2 are in opposite directions what process is it?
Respiratory (lungs)
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Explain the chemical formula for acid/base reactions
- HCl + NaHCO3 >< H2CO3 + NaCl
- hydrochloric acid + sodium bicarb >< carbonic acid + sodium chloride
- strong acid + strong buffer base >< carbonic acid + sodium chloride
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what are the regulatory systems that control pH balance?
- 1. Buffer system (chemical regulators)
- 2. Lungs (physiologic regulator)
- 3. Cells (biologic regulator)
- 4. Kidneys (physiologic regulator)
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Explain the buffer system that controls pH balance
- Chemicals that can donate or accept H+ ions
- Regulates H+ ion concentration by maintaining ration of 20 parts bicarb base to one part carbonic acid
- Reacts immediately
- Disadvantage:cannot sustain
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Explain how the lungs balance pH
- Controls the H2CO3 (carbonic acid) component of the HCO3/H2CO3 buffer system. Regulates carbonic acid level by alterating rate & depth of respirations
- If you have too much acid (excess CO2) respiratory rate & depth increases enabling "blowing off" CO2
- Rapid regulators, within minutes
- Controls CO2 content of ECF by adjusting ventilation in response to amount of CO2 in blood
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Explain how the cells balance pH
- capable of admitting or releasing excess H+ ions
- Slow regulators
- whenever excess H+ ions cross cell membranes must be either exchanged for ions of same charge or accompanied by ions of opposite charge
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Explain how kidneys balance pH
- Regulates HCo3 (bicarb) in HCO3/H2CO3 buffer system
- Also eliminates metabolic acid (lungs regulate carbonic acid)
- Kidneys alter rate of excretion of H+ &
- HCO3 in urine
- Slowest of all regulating systems, takes few hours to several days
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