Buffering Flashcards
What is buffering?
Buffering is chemical or physiological changes that work to moderate changes in pH within the body.
What is the range of pH within arterial blood?
7.35-7.45
What is the result of an increase in H+ ions?
Acidosis, a decrease in blood pH
What is the result of a decrease of H+ ions?
Alkalosis, an increase in blood pH
What do buffering systems do within the body?
Reduce changes in pH to prevent organ damage.
What is chemical buffering?
Chemical buffering is the first line of defense, with an immediate response. Chemical buffering is reversible, if there is an increase in H+, weak acid will be formed. If there is too little H+, weak acids will be split to release extra hydrogen ions.
Name 3 major buffering systems within the body.
Bicarbonate system: Carbonic acid and sodium bicarbonate
Phosphate system: Phosphoric acid and Sodium phosphate
Protein - Intracellular or within venous blood.
What is physiological buffering?
The second line of defense that only occurs when a change in pH has already happened.
What happens during renal buffering?
Renal tubules secrete ammonia and hydrogen ions into the urine and reabsorb alkaline buffers. It is the only pathway to eliminate acids, other than carbonic acid which can be dissociated into C)2 and water, and removed through respiration.
Name 2 physiological buffers.
Renal buffering
Ventilatory buffering
What happens during ventilatory buffering?
An increase in PCO2 increase the concentration of hydrogen ions in the blood due to the carbonic acid reaction. The increase in H+ stimulates ventilatory control, increasing alveolar ventilation and CO2 removal.
What does the P stand for in PCO2 and PO2?
Partial pressure of a gas (concentration of the gas)
During the carbonic acid buffering system, what is the main reaction?
H+ + HCO3- H2CO3 CO2 + H2O
How does the body replenish phosphate levels during carbonic buffering?
The kidneys can secrete H+ ions to create more HCO3-. Water also dissociates into OH- + H+. OH- + CO2 –> HCO3-.
