Acid-Base Physiology Flashcards
Definitions of acids and bases
Acids:
- substances that donate H+ ions
- pH < 7 = acidic
- saliva is slightly acidic
- too much acidic =. Acidosis
Bases:
- substances that accept H+ ions
- pH > 7 = basic
- blood is slightly basic
- too much basic = alkalosis
Buffer definition
Solutions that minimize changes in pH since the solution can reversibly donate or accept H+ ions
- prime example is bicarbonate
Ph equation
Log (1/H+) = -log(H+)
Two types of acids within the body
Volatile acid
- produced in the form of CO2 in from cellular metabolism
- reacts w/ water to produce carbonic acid
- easily able to get out via ventilation and vaporization
Nonvolatile acid
- sulfuric acid and phosphoric acids produced via protein/phospholipid catabolism
- does not react with water
- difficult to get out (must go through kidneys or liver, and do not vaporize
- this is the type of acid that is buffered by bicarbonate ions*
Ways CO2 is transported
RBC transport (90%)
- dissolved
- bound to hemoglobin
- bicarbonate ions
Plasma transport (10%)
- dissolved
- bicarbonate ions
Bicarbonate ion transferring is the most common way CO2 moves through the blood(70%)
Factors that shirt hemoglobin binding curve to the left and right
Left shift
- decrease temp
- decrease partial pressure of CO2
- increased pH
- decrease 2,3 DPG
Right shift
- increase temp
- increase partial pressure of CO2
- decrease pH (Bohr effect)
- increase 2,3 DPG
Haldane effect
Oxygen binding affinity to hemoglobin directly impacts CO2’s binding affinity to hemoglobin inversely proportionally
Less O2 bound = CO2 affinity for hemoglobin increases
Intracellular vs extracellular buffers
Intracellular:
- proteins
- organic phosphates
Extracellular:
- bicarbonate
- phosphate groups
Bicarbonate
Main extracellular buffer in the body
Acidic form = H2CO3 or CO2
Basic form = HCO3-
under normal controls, the basic form predominates over the acidic form (98:2)
Alveolar ventilations effect on pH
Normal rates = no change
Increased rates = makes pH more basic
Decrease rates = makes pH lore acidic
Definitions of the following
- acidemia
- alkalemia
- acidosis
- alkalosis
Alkalemia:
- pH in blood is above 7.4 pH
- decreases in H+ ions in the blood
Acidemia:
- pH in blood is less than 7.4 pH
- increases in H+ ions in the blood
Acidosis:
- the processes that lead to the accumulation of hydrogen ions and acidemia
Alkalosis:
- the processes that lead to accumulation of hydrogen ions and alkalemia
The blood buffer line
A line in the Davenport diagram that indicates the relationship between the pH and HCO3- concentrations
Respiratory acidosis effect on pH and HCO3-
Increases concentration of CO2 in blood which causes a decrease in pH
- fixed by bicarbonate excretion from the kidneys
Metabolic acidosis effects
Increases H+ ions and lowers blood pH
- fixed via ventilation increase and reducing CO2 concentrations
