Does acid have more or less ions?
More H+ ions
Does base have more or less ions?
Fewer H+ ions in a solution that can accept H+ ions
Why is acid-base balance important?
- Cell membrane integrity
- Cellular enzymatic speed
- Speed at which interactions in body happen
Where do acids come from ?
- Metabolic processes
- NOrmal by-product of nutrient absorption and metabolism
- Buffered by body systems
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
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
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
Where does bicarb come from?
Where does CO2 come from ?
What are acid-base regulators?
Chemical, biological, physiological
Explain chemical regulation
Carbonic acid is first to react, happens in seconds
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
- Hemoglobin-oxyhemoglobin system
- Chloride shift
Explain physiological regulation
- 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
Explain physiological regulation in regard to 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
What is a normal pH?
What is a normal PaCO2 (partial pressure depth of ventilation)?
What is a normal PaO2?
What is a normal O2 saturation?
What is normal base excess?
What is normal HCo3?
What do kidneys do for acid/base buffer?
Excrete to obtain buffer for extracellular fluid
Hyperventilation with PaCO2
Below 35 mmHg
Hypoventilation with PaCO2
increased 45 mmHg
Explain respiratory acidosis and when it occurs
H2CO3 excess, During hypoventilation, pH is decreased, CO2 is increased, Carbonic acid is increased
Explain respiratory alkalosis and when it occurs
Hyperventilation, asthma, anxiety, Increased pH, PaCO2 decreased, CO2 decreased, H2CO3 deficit
Explain metabolic acidosis and when it occurs
Decreased bicarb, happens if too much diarrhea or renal disease,reversed by lungs, HCO2 deficit
Explain metabolic alkalosis and when it occurs
Increased bicarb, HCO3 excess, due to vomiting, too much GI suctioning, K+ deficiency
What happens if you have too much CO2?
What if you have not enough CO2?
what happens if you hyperventilate?
What happens if you have hypoventilation?
When does acid-base balance occur?
When acid/base excretion=acid/base production
What does acid/base balance do?
Maintains cellular integrity, speeds up cellular enzymatic processes
What is acid/base regulated by
Chemical, biological and physiological processes
What is the first line of defense for regulation?
The chemical buffering system
what two organs does regulation happen through?
biologic and physiologic of lungs and kidneys
What happens if you have increased HCO3 if it is above 26?
What happens if you have decreased HCO3 if it is below 22?
What happens if you have increased PCO2 above 45?
What happens if you have decreased PCO2 if it is below 35?
If there are changes in the kidneys what process is it?
If there are changes in the lungs what process is it?
If the pH and HCO3 are going in the same direction what process is it?
If pH and CO2 are in opposite directions what process is it?
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
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)
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
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
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
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