acid base balance

Question 1

what is an acid?

Answer 1

proton donator

Question 2

what is a base?

Answer 2

proton acceptor

Question 3

what is pH?

Answer 3

-log10[H+]

Question 4

what does a lower pH mean?

Answer 4

acidic

Question 5

what does a higher pH mean?

Answer 5

alkali

Question 6

what is the ECF pH range?

Answer 6

7.35-7.45

Question 7

what is acidosis?

Answer 7

when pH falls below 7.35

Question 8

what is alkalosis?

Answer 8

when pH rises above 7.45

Question 9

what are metabolic sources of H+?

Answer 9

carbohydrates - carbonic and lactic acid
proteins - sulfuric acid
fats - acidic ketone bodies
DNA - sulfuric acid

Question 10

what are the systems in place to regulate H+ levels?

Answer 10

chemical buffers

acid excretion: renal or respiration

Question 11

what is a buffer?

Answer 11

a solution that is resistant to small changes in pH

Question 12

what does an acidic buffer contain?

Answer 12

weak acid and conjugate base

Question 13

what does a basic buffer contain?

Answer 13

weak base and its conjugate acid

Question 14

what buffers are in the body?

Answer 14

phospate
protein
bicarbonate
haemoglobin

Question 15

what is the phosphate buffer equation?

Answer 15

H+ + HPO4^2- –> H2PO4^2-

Question 16

explain how protein buffers work?

Answer 16

if pH falls (too acidic) - amine group of protein acts as a base and accepts a proton (NH3+)

if pH rises (to alkali) - carboxyl group acts as an acid and donates a H+

Question 17

why does the protein buffer system have such a large effect?

Answer 17

bc there are so many proteins

Question 18

what sources can bicarbonate buffer system buffer H+ from?

Answer 18

any source other than CO2

Question 19

put the buffers of the body in order of highest to lowest buffer capacity

Answer 19

bicarbonate - majority
haemoglobin
protein
phosphate - least bc its in the kidneys

Question 20

what is the equation for the haemoglobin buffer system?

Answer 20

Hb + H+ –> HHb

Question 21

what is HHb?

Answer 21

deoxyhaemoglobin

Question 22

why is the haemogloin buffer system helpful?

Answer 22

bc Hb is actively pumped around the body

Question 23

what is the normal range of CO2 in the blood?

Answer 23

35-45mmHg = 4.7-6.0kPa

Question 24

how do the lungs help in acid-base balance?

Answer 24

eliminating or retaining CO2 by changing the rate or depth of respirations

Question 25

why are the lungs quick at changing acid base balance? what limits this?

Answer 25

quick bc the brain can change respiratory rate quickly limited by the amount of CO2 expired at one time

Question 26

how do the kidneys maintain acid-base balance?

Answer 26

by excreting or conserving bicarbonate and hydrogen ions

Question 27

what is the henderson hasselbach equation?

Answer 27

acidity is inversely proportional to bicarbonate/carbon dioxide

Question 28

what do you diagnose an acid base disorder?

Answer 28

clinical history targeted physical exam ABG

Question 29

what is the mechanism of respiratory acidosis?

Answer 29

hypoventilation - more CO2 retained | or more CO2 produced

Question 30

what are the causes of respiratory acidosis?

Answer 30

``` COPD neuromuscular disorder respiratory centre depression Late acute respiratory distress syndrome inadequate mechanical ventilation sepsis/burns ```

Question 31

how will respiratory acidosis present?

Answer 31

- CO2 retained, pCO2 is high | - low pH

Question 32

what is the compensatory mechanism of respiratory acidosis?

Answer 32

renal less HCO3- produced (more resorbed) some respiratory compensation --> increased ventilation rate

Question 33

what is the mechanism of respiratory alkalosis?

Answer 33

hyperventilation

Question 34

what are the causes of respiratory alkalosis?

Answer 34

``` anxiety, stress or pain elevated body temp overventilation with ventilator CNS trauma or tumour Hypoxemia ```

Question 35

how will respiratory alkalosis present?

Answer 35

pH rises | pCO2 falls

Question 36

what is the compensation mechanism of respiratory alkalosis?

Answer 36

renal | HCO3- secreted (less reabsorbed)

Question 37

what is the mechanism of metabolic acidosis?

Answer 37

Increased H+ --> more acid production or retention Bicarbonate loss

Question 38

what are the causes of metabolic acidosis?

Answer 38

conditions that increase blood acids - renal failure, diabetic ketoacidosis, starvation and lactic acidosis chronic diarrhoea toxins carbonic anhydrase inhibitors

Question 39

how will metabolic acidosis present?

Answer 39

low pH bicarbonate falls decreased CO2

Question 40

how is metabolic acidosis corrected?

Answer 40

hyperventilation | CO2 decreased

Question 41

what is the mechanism of metabolic alkalosis?

Answer 41

HCO3- is elevated bc carbohydrate retention or loss of acid

Question 42

what causes metabolic alkalosis?

Answer 42

- acid loss due to vomiting or gastric suction - loss of potassium due to steroids or diuresis - overuse of antacids

Question 43

how does metabolic alkalosis present?

Answer 43

high pH | high HCO3-

Question 44

how is metabolic alkalosis corrected?

Answer 44

pCO2 increased | hypoventilation

Question 45

what is the normal anion gap?

Answer 45

8-12 mmol/L

Question 46

how is the anion gap calculated?

Answer 46

([K+}+{Na+)] - ([Cl-}+{HCO3-}]

Question 47

what does a high anion gap indicate?

Answer 47

loss of HCO3- without concurrent increase of Cl-