gas transport

Question 1

what does acidosis need to be corrected by

Answer 1

alkalosis (and vice versa)

Question 2

what is a rapid compensatory response to change CO2 elimination

Answer 2

changes in ventilation

Question 3

what is a slow compensatory response to change pH

Answer 3

changes in HCO3- and H+ retention/secretion in kidneys

Question 4

define acid-base homeostasis

Answer 4

acid production and clearing equal to ECF pH 7.4 optimum

Question 5

why is acid-base homeostasis required

Answer 5

receptor/enzyme binding and membrane transport

Question 6

causes of respiratory acidosis

Answer 6

hypoventilation (reduced diffusion gradient for CO2)

Question 7

pH, PCO2 and base excess in respiratory acidosis

Answer 7

low pH, high PCO2, normal base excess

Question 8

acute phase of partial respiratory acidosis compensation

Answer 8

CO2 moves into erythrocytes → combines with H2O in presence of carbonic anyhdrase → H+ and HCO3- produced → HCO3- moves out by AE1 transporter → raised base excess → shift equilibrium backwards to reduce H+

Question 9

chronic phase of partial respiratory acidosis compensation

Answer 9

increased HCO3- reabsorption in kidneys to stabilise pH

Question 10

full compensation of respiratory acidosis

Answer 10

normalise pH with large PCO2 and base excess

Question 11

causes of respiratory alkalosis

Answer 11

hyperventilation (increased gradient for CO2)

Question 12

pH, PCO2 and base excess in respiratory alkalosis

Answer 12

high pH, low PCO2, normal base excess

Question 13

acute phase of partial respiratory alkalosis compensation

Answer 13

none

Question 14

chronic phase of partial respiratory alkalosis compensation

Answer 14

reduced HCO3- absorption from nephrons and increased secretion in collecting duct, causing more H2CO3 dissociation so reducing base excess

Question 15

full compensation of respiratory alkalosis

Answer 15

normalise pH with low PCO2 and base excess

Question 16

causes of metabolic acidosis

Answer 16

diarrhoes (or other forms of H+ gaining or HCO3- losing)

Question 17

pH, PCO2 and base excess in metabolic acidosis

Answer 17

low pH, normal PCO2 and low base excess

Question 18

partial compensation of metabolic acidosis

Answer 18

increased ventilation rate, increasing diffusion gradient and reducing PCO2, causing equilibrium to shift left and formation of H2CO3

Question 19

full compensation of metabolic acidosis

Answer 19

normalise pH with low PCO2 and base excess

Question 20

causes of metabolic alkalosis

Answer 20

vomiting (or other forms of H+ losing or HCO3- gaining)

Question 21

pH, PCO2 and base excess in metabolic alkalosis

Answer 21

high pH, normal PCO2, high base excess

Question 22

partial compensation of metabolic alkalosis

Answer 22

reduced ventilation rate to increase arterial PCO2, causing equilibrium to shift right and dissociation into H+ and HCO3-

Question 23

full compensation of metabolic alkalosis

Answer 23

normalise pH with high PCO2 and base excess