made by Ayman M Hany

1. Physical
Chemistry

2. Types of Solutions
Classification
According to the pH of the solution
Solutions
Neutral Acidic Alkaline

3. Neutral Acidic Alkaline
pH 7 < 7 > 7
Examples
Pure water
&
NaCl in
water
Acetic acid
&
HCl
Ammonium
hydroxide
&
NaOH

4. Physiological Buffers
• It is very important to keep the pH of the blood
and tissues around 7.4 which is suitable for the
functions of most body enzymes.

5. Physiological buffers include:
1) Carbonic/ bicarbonate system (H2CO3/BHCO3)
2) Acid phosphate/ alkaline phosphate system
(BH2PO4/B2HPO4)
3) Acid protein/ proteinate salt system (H-proteinic
acid/B-proteinate)
4) Hemoglobin/ oxy hemoglobin system in RBCs.
• B means Na+ in extracellular or K+ in
intracellular buffers.

6. Mechanism of action of buffers:
• In case of addition of strong acid like HCl, it is
converted into weak acids by buffer.
• NaHCO3+ HCl NaCl+ H2CO3

7. The most important physiological
buffer system:
• The carbonic/bicarbonate system is the most
important buffer, because
it is present in high concentration and
carbonic acid is easily formed from CO2 in the tissues
• H2CO3 Carbonic anhydrase CO2 + H2O

8. At pH 7.4, the ratio between
H2CO3 and BHCO3 is 1/20

9. Acidosis
Definition:
It is a condition in which H2CO3/BHCO3 is increased
more than 1/20.

10. Acidosis
Respiratory Acidosis:
1) Failure of the lungs to excrete H2CO3 in severe lung
diseases.
2) Depression of respiratory center by morphine.

11. Acidosis
Metabolic acidosis
1) Increased production of acids inside the body as in:
– Ketosis: in uncontrolled diabetes mellitus and in
starvation, due to decrease oxidation of carbohydrates
and increase oxidation of fatty acids which give ketone
bodies.
– Severe muscle exercise produces large amount of lactic
acid.
– High protein diet produces phosphoric, sulfuric and uric
acids.

12. Acidosis
Metabolic acidosis
2) Renal acidosis: in renal failure, the kidneys can
not excrete acids.
3) Excessive loss of bases: in severe vomiting and
diarrhea (loss of alkaline intestinal juice).

13. Acidosis
Compensation:
• In respiratory acidosis:
by increasing excretion of acids and increasing
reabsorption of bicarbonate by the kidneys.
• In metabolic acidosis:
by increasing rate of respiration to remove CO2 from
blood by the lungs.

14. Alkalosis
Definition:
It is a condition in which H2CO3/BHCO3 is decreased
less than 1/20.

15. Alkalosis
Respiratory Alkalosis
1) In fever
2) High altitudes.
In all these conditions hyperventilation occurs
leading to increase loss of CO2 and decrease
H2CO3 in the blood.

16. Alkalosis
Metabolic Alkalosis
1) Loss of acidic gastric juice by vomiting or
repeated gastric wash.
2) Large amounts of fruits and vegetables in diet as
it contain large amount of salts of organic acids
which can increase bicarbonate.
3) In the treatment of peptic ulcers by taking
bicarbonate.

17. Alkalosis
Compensation:
• In Respiratory Alkalosis:
The kidneys increase the excretion of HCO3
- and
decrease excretion of H+.
• In Metabolic Alkalosis:
Depression of the respiratory center occurs, so there is
decreased excretion of CO2 by the lungs. This
produces an increase of H2CO3 in blood and
correction of H2CO3/BHCO3 ratio.