CGIER 40 - Buffer systems of the body

Question 1

buffer system

Answer 1

CHEMICAL EQUILIBRIA systems that typically consist of a weak acid and weak base of equal quantities and resist serious changes in pH upon addition of acids or bases.

Question 2

what do metabolic reaction produce

Answer 2

continuously produce acids

Question 3

how much carbonic acid do cells produce each day

Answer 3

produce an average of ~ 10-20 moles of carbonic acid each day (equivalent to 1-2 litres of concentrated HCl).

Question 4

how is carbonic acid removed from body produced by cells

Answer 4

removed from the cells and carried to the organs of excretion without disrupting the pH of the blood.

Question 5

what buffer system controls ph of blood

Answer 5

the pH of the blood is controlled by the bicarbonate buffer system

Question 6

name the pH buffer that works in cells

Answer 6

phosphate buffer

Question 7

phosphate buffer system

Answer 7

H2PO4- <===> H3O+ + HPO4^2-

Question 8

bicarbonate buffer system

Answer 8

CO2 + H2O <===> H2CO3 <===> H3O+ + HCO3-

Question 9

what feature can describe proteins

Answer 9

amphoteric.

Question 10

NH2CCOOH products of amino acid

Answer 10

NH3+

COO-

Question 11

Le Chatelier’s Principle

Answer 11

If the conditions of a system, initially at equilibrium, are changed, the equilibrium will shift in such a direction as to tend to restore the original conditions.

Question 12

where will the bicarbonate buffer system shift if a strong acid is added

Answer 12

• driving the reaction to the left and forming more carbonic acid
• carbonic acid is unstable and will decompose rapidly to form carbon dioxide and water

Question 13

where will the bicarbonate buffer system shift if a strong base is added

Answer 13

• base will react with the H3O+ ions present to produce water
• thus decreasing the [H3O+] in the system.
• this will drive the above reaction to the right.

Question 14

an abnormal increase in acid levels in blood can lead to …

Answer 14

respiratory acidosis

metabolic acidosis

Question 15

how does body try to compensate for respiratory acidosis and metabolic acidosis

Answer 15

expelling the excess carbon dioxide formed from the carbonic acid, through an increase in the rate of breathing.
increasing the excretion of H+ and the retention of HCO3- by the kidneys.

Question 16

what does respiratory acidosis result from

Answer 16

CO2 retention

pH blood decreases

Question 17

causes of respiratory acidosis

Answer 17

hypoventilation
emphysema or asthma
congestive heart failure
Bronchopneumonia
drugs that depress the brain 
respiratory centre

Question 18

what does metabolic acidosis result from

Answer 18

increase in H+

pH decrease in blood

Question 19

causes of metabolic acidosis

Answer 19

diabetes mellitus - acidic compounds formed from metabolism of fats
kidney failure
severe diarrhoea causing loss of HCO3-
excessive exercise

Question 20

compensatory of metabolic and respiratory acidosis

Answer 20

increase rate of breathing

kidneys excrete acid urine

Question 21

AN ABNORMAL DECREASE IN ACID LEVELS IN BLOOD.

The pH of the blood increases.

Answer 21

‘Respiratory Alkalosis’

Metabolic Alkalosis’

Question 22

how does body try to restore normal pH when the blood is in alkalosis

Answer 22

expelling less carbon dioxide by decreasing the rate of breathing.
increase the excretion of HCO3- by the kidneys, resulting inalkaline urine (pH>7).

Question 23

what results in respiratory alkalosis

Answer 23

rapid expulsion of CO2 (elevated breathing rate)

blood pH increases

Question 24

causes of respiratory alkalosis

Answer 24

hyperventilation
high fevers
trauma
hysteria

Question 25

compensatory for respiratory and metabolic alkalosis

Answer 25

slower rate of breathing

kidneys excrete less acid

Question 26

what does metabolic alkalosis result from

Answer 26

increase in alkaline components such as HCO3- in blood

blood pH increases

Question 27

causes of metabolic alkalosis

Answer 27

severe vomiting - loss of acid stomach
excess ingestion of alkaline substances
kidney disease

Question 28

acidosis equation

Answer 28

CO2 /\ + H2O H2CO <=>HCO3- + H3O+(excreted in urine)

Question 29

alkalosis equation

Answer 29

CO2 V + H2O H2CO3 <==> HCO3-(excreted in urine) + H3O+

Question 30

where will the phosphate buffer system shift to if a strong acid is added

Answer 30

will drive the reaction to the left,
• thus increasing the [H2PO4-] in the system (which is only weakly acidic).
Large amounts of H2PO4- will result in acidosis, but the body will eliminate the excess in urine.

Question 31

where will the phosphate buffer system shift to if a strong base is added

Answer 31

• will drive the reaction to the right as the H+ ion reacts with the base to form water
Large amounts of HPO42- would be found in alkalosis, but under normal kidney function, the HPO42- is also excreted in the urine.