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3 Cards in this Set
- Front
- Back
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ph of body fluids |
A. Definition of pH- a number that indicates the hydrogen ion concentration of a fluid
B. Normal arterial blood pH- about 7.45
C. Normal venous blood pH- about 7.35 |
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Mechanisms that control pH of Body fluids
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A. Buffers 1. Definition- substacnes taht prevent a sharp change in the pH of a fluid when an acid or base is added to it 2. Fixed acids are buffered mainly by sodium bicarbonate 3. Changes in blood produced by buffering of "fixed" acids in the tissue capillaries a. amoutn of carbonic acid in blood increases slightly b. amount of NaHCo3 in blood decreases; ratio of amount of NaHCO3 to the amount of H2CO3 does not normally change; normal ratio is 20:1 c. hydrogen ion concentration of blood increases slightly d. Blood pH decreases slightly below arterial level
B. Respiratory mechanism of pH control- respirations remove some Co2 from blood as blood flows through lung capillaries, the amount of H2CO3 in blood is decreased and thereby its hydrogen ion concentration is decreased, anmd thsi in turn increases blood pH from its venous to its arterial level
C> Urinary mechanism of pH control- being that body's most effective regulator of blood pH, kidney's usually acidify urine by the distal tubules secreting hydrogen ions and ammonia into the urine from blood in exchange for NaHCO3 being reabsorbed into the blood |
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pH imbalacnes |
A. acidosis and alkalosis- pH or acid-base imbalances
B. Disturbances in acid-base balance depend on relative quantities of NaHCO3 and H2CO3 in the blood
C. Body can regulate both of the components of the NaHCO3-H2CO3 buffer system 1. blood levels of NaHCO3 regutaed by kidneys 2. H2Co3 levels regulated by lungs
D. Metabolic and repsiratory disturbances- pH distrubances- can alter the normal 20:1 ratio of NaHCO3 to H2Co3 in blood 1. MEtabolic disturbances affect the NaHCo3 levels in blood 2. Respiratory disturbances affect the H2CO3 level sin blood.
E. Metabolic disturnbances 1. Metabolic acidosis- bicarbonate (NaHCO3) deficit 2. metabolic alkalosis- bicarbonate (NaHCO3) excess; complication of severe vomiting
F. Respiratory disturbances 1. Respiratory acidosis (H2CO3) excess 2. Respiratory alkalosis (H2CO3) deficit
G. in uncompensatedmetaboli acidosis, the normal ratio of NaHCO3 to H2CO3 is changed; in compensated metabolic acidosis, the ratio remains close to 20:1, but the total amount of NaHCO3 and H2CO3 changes
H. Cardiac arrest and respiratory acidosis |
