THE PHYSIOLOGICAL AND CHEMICAL CONTROL SYSTEMS THAT HELP IN MAINTENANCE OF pH IN BODY IS EXPLAINED IN THE PRESENTATION

1. REGULATION OF
HYDROGEN ION
CONCENTRATION IN
HUMAN BODY

2. INTRODUCTION
 HOMEASTASIS
 FLUID CONTENT
 EXTRA CELLULAR FLUID
 INTRA CELLULAR FLUID
 WATER IN THE BODY

3. ACIDS AND BASES
 WHAT ARE ACIDS
 WHAT ARE BASES
 RECAP OF CONCEPTS
 HYDROGEN ION IN BODY
 pH

4. CONTROL SYSTEMS
CHEMICAL
CONTROL
BICARBONATE
BUFFER PAIR
PHOSPHATE
BUFFER PAIR
PROTIEN
BUFFER PAIR
PHSIOLOGICAL
CONTROL
RESPIRATORY
CONTROL
SYSTEM
RENAL
CONTROL
SYSTEM

5. CONTROL SYSTEMS
 BUFFER PAIRS
 BICARBONATE BUFFER PAIR
 EG:ADDITION OF ACIDS AND BASES
 HAEMOGLOBIN BUFFER
 LACTATE BUFFER
 PHOSPHATE BUFFER PAIR
 PROTEIN BUFFER PAIR

6. PHYSIOLOGICAL CONTROL
SYSTEM
 RESPIRATORY CONTROL SYSTEM
 HYPERCAPNIA
 HYPOCAPNIA
 HYPERVENTILATION
 HYPOVENTILATION

7. RENAL CONTROL SYSTEM
 REABSORPTION OF BICARBONATE ION
 RETENTION OF BICARBONATE ION

8. Introduction
 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

9. Acids
 Proton donors
 Acidity reflects on free hydrogen ions
 Strong acids dissociate completely, liberate all H+ ions
 Weak acids dissociate partially

10. Bases
 Bases are proton acceptors
 Strong bases dissociate quickly and tie up H+ions
almost immediately.
 Weak bases slowly accept protons.

11. 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.

12. Continued…
 Acids and bases continually enter and exit body.
 H+ ions enter through
Carbonic acid and lactic acid – via aerobic and anaerobic
respiration
Sulphuric acid-S+ containing amino acid oxidation
Phosphoric acid- phosphoproteins and ribonucleotides break
down
Acidic ketone bodies- including acetone, acetoacetic acid and
beta-hydroxybutyric acid thru’ incomplete breakdown of fats

13.  Minerals after metabolises may be acid forming or basic
forming minerals.
 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
forming food
 Antacids- sodium bicarbonate and calcium bicarbonate –
direct base forming materials

14. Homeostasis
 Carbonic anhydrase enzyme.

15. Control systems

16. Chemical Control Sytem

18. Bicarbonate Buffer Pairs
 ECF buffer
 When strong acid is added pH is lowered.
 Hence this buffer pair forces the addition of strong base that
neutralizes this effect.
 Chloride shift
 Bicarbonate loading.
 RATIO OF ACID:BASE=20:1
 Increase is uncompensated acidosis (uncompensated
alkalosis.

19. Phosphate Buffer Pair
 Sodium salts of dihydrogen phosphate and
monohydrogen phosphate.
 H+ released by strong acid is tied up by weak acids
 Strong bases are converted in to weak bases.
 Buffer of ICF and urine.

20. 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.

21. Respiratory Control

23.  Carbon dioxide is expelled from lungs, during its
unloading the balance is shifted and hydrogen ions are
liberated from carbonic acid and reincorporated into
water.
 Due to protein buffer hydrogen ion is not accumulated
and dos not affect blood pH.
 Hypoventilation causes acidosis
 Hyperventilation causes alkalosis

24. Renal Control System

28. Presentation by Florence
Suganya R
12/PZO/004