Acid Base control

Question 1

what is normal body pH

Answer 1

7.40

Question 2

what are the 3 main buffer systems for body pH

Answer 2

ICF/ ECF buffers
lungs eliminating CO2
Renal HCO3- reabsorption and H+ elimination

Question 3

what is the equation for carbonic acid/ bicarbonate buffer

Answer 3

• CO2 + H2O ⇆ H2CO3 ⇆ H+ + HCO3- ;

o 1st stage uses carbonic anhydrase

Question 4

what is the purpose of the carbonic acid/ bicarbonate buffer

Answer 4

works with lungs to compensate H2CO3 production

Question 5

how is CO2 directly transported in the blood

Answer 5

binds directly with Hb; reversibly combines with terminal amine group on Hb molecule to form carbaminohemoglobin

Question 6

what is an alternate method of CO2 transport in the body (that doesn’t involve formation of carbaminohemoglobin)

Answer 6

CO2 dissociates into H+ and HCO3-

• H+ bids to reduced Hb to form HHb
• HCO3- passes back into plasma in exhcnage for Cl-
• dissoaciation is reversed in lungs as H+ and HCO3- combine to form CO2

Question 7

why is HCO3- exchanged for Cl- in transport of CO2 in RBC

Answer 7

so no net loss/ gain of negative ions in RBC

Question 8

what is the partial pressure of CO2 inversely proportional to

Answer 8

alveolar ventilation

Question 9

what isthe Henderson-Hasselbach equation

Answer 9

pH = 6.1 + log10([HCO3]/0.03(pCO2))

Question 10

what is 6.1 in Henderson-Hasselbach equation

Answer 10

fixed dissociation constant for bicarbonate dissociation

Question 11

what is 0.03 in Henderson-Hasselbach equaiton

Answer 11

blood CVO2 solubility coefficient

Question 12

what is 0.03(pCO2) an estimate of in the Henderson-Hasselbach equation

Answer 12

H2CO3 concentration

Question 13

what is respiratory acidoses

Answer 13

increased PaCO2, decreased pH, mild increased HCO3-

Question 14

what are the casues of respiratory acidosis

Answer 14

respiratory failure, hypoventilation

Question 15

how is respiratory acidosis compensated over time

Answer 15

renal compensation leads to increased HCO3- so reabsorb more bicarbonate so pH increases

Question 16

what happens in respiratory alkalosis

Answer 16

decreased PaCO2, increased pH

Question 17

what are the cause(s) of respiratory alkalosis

Answer 17

hyperventilation

Question 18

what does renal compensation do in respiratory alkalosis

Answer 18

increased renal bicarbonate exretion so decreased [HCO3-] so decrease pH

Question 19

what happens in metabolic acidosis

Answer 19

reduced bicarbonate, decreased pH

Question 20

what happens in metabolic alkalosis

Answer 20

increased bicarbonate, increased pH

Question 21

what is a cause of metabolic alkalossi

Answer 21

vomiting

Question 22

is renal compensation fast or slow

Answer 22

slow - only occurs if respiratory acidosis/ alkalosis is chronic

Question 23

is respiratory compensation fast or slow

Answer 23

fast

Question 24

what do buffers do

Answer 24

resist changes in pH when small quantities of strong acid/ base added

Question 25

what improves the efficacy of the bicarbonate buffer system

Answer 25

CO2 removed by lungs, kidneys regenerating bicarbonate

Question 26

how can blood proteins act as buffers

Answer 26

contain weakly acid and base groups within structure

Question 27

how do intracellular proteins act as buffers

Answer 27

limit pH changes within cells

Question 28

how can Hb act as a buffer

Answer 28

binds CO2 and H+; is a strong buffer

Question 29

does oxygenated or deoxygenated Hb have strongest buffer effect

Answer 29

deoxygenated - because has strongest affinity