Acid-Base Balance

Question 1

what is H+ continually added from?

Answer 1

CA formation
inorganic acids produced during breakdown of nutrients
organic acids resulting from metabolism

Question 2

what does acidosis do to the CNS?

Answer 2

depression

Question 3

what does alkalosis do to the CNS?

Answer 3

overexcitability

Question 4

buffer systems when acid is added

Answer 4

equilibrium shifts to the left

protons are mopped up by A- forming HA

Question 5

buffer systems when base is added

Answer 5

equilibrium shifts to the right

combined with H+ forming HA so HA already formed dissociates

Question 6

what ion concentration do kidneys control?

Answer 6

HCO3-

Question 7

examples of buffers

Answer 7

H2PO4-

ammonia NH3

Question 8

define compensation

Answer 8

if the acid-base balance is disturbed then pH is first restored irrespective of what happens to HCO3- and CO2 concentrations

Question 9

define correction

Answer 9

everything returns to normal levels (HCO3-, CO2 and pH)

Question 10

define respiratory acidosis

Answer 10

retention of CO2 by the body

Question 11

causes of respiratory acidosis

Answer 11

chronic bronchitis or emphysema
airway restriction
chest injuries
respiratory distress

Question 12

uncompensated respiratory acidosis blood results

Answer 12

pH <7.35

pCO2 >45mmHg

Question 13

equilibrium shift in respiratory acidosis

Answer 13

right

Question 14

how does the body attempt to stop respiratory acidosis?

Answer 14

H+ is excreted by the renal system generating TA and NH4+ forming new HCO3-

Question 15

what does correction of respiratory acidosis require?

Answer 15

restoration of normal ventilation

Question 16

what is respiratory alkalosis?

Answer 16

excessive removal of pCO2

Question 17

causes of respiratory alkalosis

Answer 17

low inspired pO2 at altitude (hypoxia stimulates peripheral chemoreceptors, hyperventilation lowers pCO2)
hyperventilation (fever, brainstem damage)
hysterical over-breathing

Question 18

blood results of uncompensated respiratory alkalosis

Answer 18

pH >7.45

pCO2 <35mmHg

Question 19

define metabolic acidosis

Answer 19

excess H+ from any source other than CO2

Question 20

causes of metabolic acidosis

Answer 20

ingestion of acids or acid-producing foodstuffs
excessive metabolic production of H+ (lactic acid or ketoacidosis)
excessive loss of base from body e.g. diarrhoea loss of HCO3-

Question 21

bloods results of uncompensated metabolic acidosis

Answer 21

pH <7.35

HCO3- low

Question 22

how does the body try to stop metabolic acidosis?

Answer 22

peripheral chemoreceptors are stimulated and ventilation is increased to blow off more CO2

Question 23

what is required for correction of metabolic acidosis?

Answer 23

reabsorption of HCO3- and H+ secretion to produce TA and NH4+ for new HCO3-
acid load excreted

Question 24

define metabolic alkalosis

Answer 24

excessive loss of H+ from the body

Question 25

causes of metabolic alkalosis

Answer 25

loss of HCl from stomach (vomiting)
ingestion of alkali or alkali-producing foodstuffs e.g. antacid
aldosterone hypersecretion causes Na+/H+ exchange leading to acid secretion

Question 26

what is elevated in metabolic alkalosis?

Answer 26

HCO3-

Question 27

bloods of uncompensated metabolic alkalosis

Answer 27

pH >7.45

HCO3- high

Question 28

compensation of metabolic alkalosis

Answer 28

slow ventilation leading to retention of CO2

Question 29

correction of metabolic alkalosis

Answer 29

requires HCO3- excretion