BLOOD GASES Flashcards
→ a substance that can yield a hydrogen ion
(H+) when dissolved in wate
Acid
→ Is a substance that can yield hydroxyl ions (OH-) when
dissolved in water
Base
→ Relative strengths of acids and bases – their ability to
dissociate in water
● Dissociation Constant (K value)
pH at which the protonated (the base) and unprotonated (the
acid) forms are present in equal concentration
● pKa
→ Have pK values of less than 3.0
→ Raising the pH above the pK will cause it to dissociate and
yield a H+ (hydrogen ion)
→ Dissociates completely
● Strong acids
→ Have pK values of greater than 9.0
→ Lowering the pH below the pK will cause it to release OH-
(hydroxyl ion)
→ Dissociates completely
Strong bases
→ First line of defense
● Buffer Systems
→ Combination of a weak acid or weak base and its salt
● Buffer
▪ Resists changes in pH
● Buffer
➢ Plays a role in both plasma and red blood cells
▪ Phosphate buffer system
➢ Includes hemoglobin buffer system, amino acid buffers, and
plasma protein buffers
▪ Protein buffer system
❖ Acts as a buffer by transporting hydrogen ions from
peripheral tissues to the lungs
♦ Hemoglobin buffer system
❖ Most circulating proteins have a net negative charge,
which means that proteins are capable of binding with
hydrogen ions.
❖ If you have too much hydrogen ions inside your body, it
would indicate that your blood is acidic, the proteins will
now bind with you hydrogen ions to regulate your blood
pH
♦ Plasma protein buffers
➢ considered as the main buffer system of the extracellular fluid
▪ Carbonic acid-bicarbonate buffer system
The following organs are the main organs which participate in the
regulation of the acid-base status in the body (2)
Lungs and kidney
▪ Respiratory component
Lungs
▪ Metabolic component
KIdney
→ Pressure or tension exerted by CO2 gas dissolved in blood
→ An index of efficiency of gas exchange in the lungs
→ Not a measure of CO2 concentration in the blood
● Partial Pressure of CO2 (pCO2
→ Total CO2 Content
→ Refers to the total concentration of CO2
in the blood
→ Consisting of ionized (HCO3-
, CO3-
, carbamino compound)
and unionized fraction (H2CO3
) and physically dissolved CO2
● Total Carbon Dioxide Concentration (tCO2
→ The bicarbonate ion concentration in the blood that has been
equilibrated with CO2 at 40 mm Hg at 37
oC
● Bicarbonate Ion Concentration
→ The pressure or tension exerted by oxygen gas dissolved in
arterial blood which reflects the availability of the gas in
blood but not its content
● Partial Pressure of O2
(pO2
)
● index of the acidity or alkalinity of the blood
● it is inversely proportional to your hydrogen ion
concentration
→ this means that the more hydrogen ions present in the blood,
the lesser the blood pH, and vice versa
pH
________ is directly proportional to the blood pH
Bicarbonate
related to the acidity of the blood
Hydrogen
: related to the capacity of the blood to become basic
Bicarbonate
__________ will cause alterations in the rates of chemical
reactions within the cell and affect the many metabolic
processes of the body
→ Can lead to alterations in consciousness, neuromuscular
irritability, tetany, coma, and death
Increase H+
● Normal: 36 – 44 nmol/L (pH 7.34 – 7.44)
A. MAINTENANCE OF H+
proton donor or weak acid (H2CO3
)
HA
