22A: Acid-Base Balance

Question 1

What is the normal range of PCO2 and pH in the ECF?

Answer 1

• PCO2 = 35-45 mmHg

- pH = 7.35-7.45

Question 2

Describe sources and sinks of acids in the body

Answer 2

• respiratory system eliminates CO2 (increases pH)
• kidneys excrete H+ ions
• metabolic cells produce CO2 (decreasing pH)
• buffers may add or remove H+

Question 3

potassium buffer system

Answer 3

buffers pH of ICF and urine

Question 4

protein buffer systems

Answer 4

• includes hemoglobin buffer system, amino acid buffers, plasma protein buffers
• regulate pH in ICF and ECF

Question 5

carbonic acid-bicarbonate buffer system

Answer 5

buffers pH of ECF

Question 6

hemoglobin buffer

Answer 6

• the only intracellular buffer system that can have immediate effect of pH of bodily fluids
• H+ can dissociate and bind to Hb when it needs to

Question 7

respiratory and renal response to metabolic acidosis

Answer 7

• respiratory response: increase respiratory rate to eliminate CO2
• renal response: secrete H+ ions, removing CO2 and reabsorbing HCO3- which drives HCO3-/Cl- exchanger and consequently the H+/Cl- cotransporters

Question 8

respiratory and renal response to metabolic alkalosis

Answer 8

• respiratory response: decreased respiratory rate to decrease CO2 elimination
• renal response: kidney generates H+; actively pumped into ECF

Question 9

respiratory acidosis

Answer 9

• rate CO2 produced > rate CO2 eliminated
• increased PCO2 due to hypoventilation
• response is increase respiratory rate

Question 10

respiratory alkalosis

Answer 10

• rate CO2 eliminated > rate CO2 produced
• decreased PCO2 due to hyperventilation
• response is decreased respiratory rate