REGULATION OF HYDROGEN ION

CONCENTRATION IN HUMAN BODY

INTRODUCTIONHOMEASTASIS

FLUID CONTENT

EXTRA CELLULAR FLUID

INTRA CELLULAR FLUID

WATER IN THE BODY

ACIDS AND BASESWHAT ARE ACIDS

WHAT ARE BASES

RECAP OF CONCEPTS

HYDROGEN ION IN BODY

pH

CONTROL SYSTEMS

CONTROL SYSTEMSBUFFER PAIRS

BICARBONATE BUFFER PAIR

EG:ADDITION OF ACIDS AND BASES

HAEMOGLOBIN BUFFER

LACTATE BUFFER

PHOSPHATE BUFFER PAIR

PROTEIN BUFFER PAIR

PHYSIOLOGICAL CONTROL SYSTEM

RESPIRATORY CONTROL SYSTEM

HYPERCAPNIA

HYPOCAPNIA

HYPERVENTILATION

HYPOVENTILATION

RENAL CONTROL SYSTEMREABSORPTION OF BICARBONATE ION

RETENTION OF BICARBONATE ION

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

Acids Proton donors

Acidity reflects on free hydrogen ions

Strong acids dissociate completely, liberate all H+ ions

Weak acids dissociate partially

Bases

Bases are proton acceptors

Strong bases dissociate quickly and tie up H+ ions almost immediately.

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.

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

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

HomeostasisCarbonic anhydrase enzyme.

Control systems

Chemical Control Sytem

Bicarbonate Buffer PairsECF 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.

Phosphate Buffer PairSodium 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.

Protein Buffer PairAmino 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.

Respiratory Control

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

Renal Control System

Presentation by Florence Suganya R

12/PZO/004