REGULATION OF HYDROGEN ION CONCENTRATION IN HUMAN BODY
EXTRA CELLULAR FLUID
INTRA CELLULAR FLUID
WATER IN THE BODY
ACIDS AND BASES
WHAT ARE ACIDS
WHAT ARE BASES
RECAP OF CONCEPTS
HYDROGEN ION IN BODY
BICARBONATE BUFFER PAIR
EG:ADDITION OF ACIDS AND BASES
PHOSPHATE BUFFER PAIR
PROTEIN BUFFER PAIR
RESPIRATORY CONTROL SYSTEM
RENAL CONTROL SYSTEM
REABSORPTION OF BICARBONATE ION
RETENTION OF BICARBONATE ION
60% of male body is water
50% of female body is water
2/3 of the body is ICF
1/3 of the body is ECF
INPUT: water in food, ingested liquid
OUTPUT: water vapor, sweat, urine, feces
Bases are proton acceptors
Strong bases dissociate quickly and tie up H+ions
Weak bases slowly accept protons.
What is pH?
The amount of hydrogen ions present in the solution.
1- 14 ranges the pH scale. 7 is neutral. Below 7 is
acidic. Above 7 is basic.
pH of arterial blood when above 7.45 causes alkalosis.
pH below 3.5 causes acidosis.
Acids and bases continually enter and exit body.
H+ ions enter through
Carbonic acid and lactic acid – via aerobic and anaerobic
Sulphuric acid-S+ containing amino acid oxidation
Phosphoric acid- phosphoproteins and ribonucleotides break
Acidic ketone bodies- including acetone, acetoacetic acid and
beta-hydroxybutyric acid thru’ incomplete breakdown of fats
Minerals after metabolises may be acid forming or basic
Acid forming minerals- chlorine, sulphur, phosphorus
(present in meat, fish, poultry, eggs, wheat, corn, oats)
Base forming minerals- potassium, calcium, sodium,
magnesium (present in dry fruits and vegetables)
Rhubarb (oxalic acid),cranberries (benzoic acid)- direct acid
Antacids- sodium bicarbonate and calcium bicarbonate –
direct base forming materials
Bicarbonate Buffer Pairs
When strong acid is added pH is lowered.
Hence this buffer pair forces the addition of strong base that
neutralizes this effect.
RATIO OF ACID:BASE=20:1
Increase is uncompensated acidosis (uncompensated
Phosphate Buffer Pair
Sodium salts of dihydrogen phosphate and
H+ released by strong acid is tied up by weak acids
Strong bases are converted in to weak bases.
Buffer of ICF and urine.
Protein Buffer Pair
Amino acids have exposed groups that act as bases
and accept H+
A single protein molecule may be acidic or basic
depending on pH.
They are amphoteric in nature.
Hb is an intracellular buffer.
Carbon dioxide is expelled from lungs, during its
unloading the balance is shifted and hydrogen ions are
liberated from carbonic acid and reincorporated into
Due to protein buffer hydrogen ion is not accumulated
and dos not affect blood pH.
Hypoventilation causes acidosis
Hyperventilation causes alkalosis