CHIORIDES AND BICARBONATES

1. Electrolyte balance
* **chlorides &
bicarbonates** *
By Ranjith.N
Pharm.D 1 st year
Care college of
pharmacy......

2. Source of chlorides
• Chlorine is a constituent of NaCl, hence , the
metabolism of chlorine and sodium are
intimately related
• Common salt as cooking medium
• Whole grains
• Leafy vegetables
• Eggs
• Milk

3. Bio chemical functions of chlorides
• Chlorides is involved in the regulation of acid
base equilibrium, fluid balance and osmotic
pressure
• These functions are carried out by the
interaction of cl- with Na+ and K+
• Chlorides are necessary for the formation of
HCL in the gastric juice
• Chloride shift involved in the active
participation of chloride
• The enzyme salivary amylaze is activated by

4. Dietary requirement of chlorides
• The daily requirement of chloride as NaCl is 5-
10g" adequte intake of sodium will satisfy the
chloride requirment of the day

5. lPlasma chloride
• The normal plasma concentration of chloride
is 95-105mEql
• Cerebrospinal fluid contains higher level of Cl-
125mEq/l
This is due to the fact that protein content is low
in CSF and there fore, the chloride is higher in
order to maintain donnan membrane
equilibrium

6. a. Absorption
b. Excretion
• a) In normal circumstances, chloride is almost
totally absorbed in the gastrointestinal track
• b)There exists a paralled relationship between
excretion of chloride and sodium.
• The renal threshold for chloride is about
110mEq/l

7. If chloride is deficiency in our
body???
üDisease states ........
1.Hypochloremia: A reduction in the serum
chloride level may be occur due to vomiting,
diarrhea, respiratory alkalosis, Addison's
disease and excessive sweating ......
2.Hyperchloremia: An increase in serum
chloride concentration may be due to
dehydration, respiratory acidosis and
Cushing's syndrome

8. Source of bicarbonates
• The formation of basic compounds in the
body, in th normal circumstances, is negligible.
• Some amount of bi carbonates is generated
from the organic acids such as lactate and
citrate..
• Sodium bi carbonate and carbonic acid..

9. Biological functions of
bicarbonates
• Maintenance of Blood pH
• The body beveloped three lines of defense to
regulate the body's acid-base balance and
maintain the Blood pH (around 7.4)
1.Blood buffers
2.Respiratory mechanism
3.Renal mechanism

10. *Blood buffers*
• A buffer may be defined as a solution of a
weak acid and it's salt with a strong base
• The buffer resisits the change in pH by the
addition of acid or alkali and the buffering
capacity is dependent on the absolute
concentration of salt and acid.....
• Buffers cannot remove the H+ ions from the
body. It temporarily acts as a shock absorbent
to reduce the free H+ ions.
• The H+ ion eliminated by the renal mechanism

11. The blood contains 3 buffers
systems
1.Bicarbonate buffer system
2.Phosphate buffer system
3.Protein buffer system

12. 1.Bicarbonate buffer system
• Sodium bicarbonate and carbonic acid is the
most predominant buffer system of the
extracellular fluid, particularly the plasma..
• Carbonic acid is dissociates into hydrogen
and bicarbonate ions
• H2CO3<...........>H+ + HCO3
• By the law of mass action, at equilibrium
• Ka={H+} [HCO3]/H2CO3 .....(1)
• [Ka=dissociation constant of H2CO3]

13. 1.Bicarbonate buffer system
• The equation may be rewritten as follows
[H+]=Ka[H2CO3]/HCO3 -.......(2)
We know that pH=log 1/[H+]
By taking the reciprocals and logarithms
log 1 /[H+]=log 1/Ka+log[HCO3-]/[H2CO3]..(3)
log 1 /Ka=pKa
The equation 3 may now be written as
PH=pKa+log[HCO3-]/H2CO3.....(4)

14. Henderson-Hasselbalch equation
• The above equation is valid for any buffer
pair.
• The general equation for any buffer is written
as
pH=pKa+log[Base]/[Acid]....(5)
It is the evident from this equation that the pH is
dependent on ratio of the concentration of the
base and acid(HCO3-& H2CO3 in Eqn 4)

15. Blood pH and the ratio of HCO3- to
H2CO3
• The plasma bicarbonate concentration is a
round 24mmol/l.
• Carbonic acid is a solution of CO2 in water.
• It's concentration is given by the product of
pCO2 and the solubility constant of CO2
• Thud H2CO3=40×0.03=1.2mmol/l..
• Thus Henderson- Hasselbalch equation for
bicarbonate buffer is
• pH=pKa+log[HCO3-]/H2CO3]

16. Blood pH and the ratio of HCO3- to
H2CO3
• Substituting the values
• Blood pH=7.4
• pKa for H2CO3=6.1
• HCO3-=24mmol/l
• H2CO3=mmol/l in the above equation
• 7.4=6.1+log(24)/1.2
• 7.4=6.1+log20
• 7.4=6.1+1.3
• 7.4=7.4

17. Blood pH and the ratio of HCO3- to
H2CO3
• It is evident thet at ablood pH 7.4, the ratio of
bicarbonate to carbonic acid is 20:1
• Thus, the bicarbonate concentration is
much higher than carbonic acid in the blood
• The concentration of the bicarbonate and
carbonic acid determines the pH of blood .

18. phosphate and protein buffer
system
• Sodium dihydrogen phosphate & di sodium
hydrogen phosphate constitute the
phosphate buffer.
• The plasma proteins and heamoglobin
together constitute the protein buffer system
of the blood.

19. 2.Respiratory mechanism for pH
regulation
• Respiratory buffer system provides a rapid
mechanism for the mainteance of acid base
balance.
• This is achieved by regulating the
concentration of carbonic acid in the blood.
Carbonic anhydrase
H2CO3<....................................>CO2+H2O

20. 3.Renal mechanism for pH
regulation
• The role of kidneys in the maintaenance of
acid base balance of the body is high
significant.
• The renal regulation of pH which occurs by the
following mechanism...
üExcretion of H+ ions.
üReabsorption of bicarbonates.
üExcretion of titratable acid.
üExcretion of ammonium ions.

21. 3.Renal mechanism for pH
regulation
• Excretion of H+ ion

22. 3.Renal mechanism for pH
regulation
• Reabsorption of bicarbonate

23. Disorders of acid base balance
• The blood pH compatible to life is 6.8-7.8,
beyond which life cannot exis
• The acid base disorders are mainly classified
as
• (1)Acidosis-a decline in blood pH
a.Metabolic acidosis - due to decrease in
bicarbonate.
b.Respiratory acidosis-due to an increase in
carbonic acid

24. Diso
• (2)Alkalosis-a rise in blood pH
a.Metabolic alkalosis- due to an increase in
bicarbonate.
b.Respiratory alkalosis- due to a decrese in
carbonic acid
Disorders of acid base balance

25. Disorders of acid base balance

26. Disorde
Disorders of acid base balance

27. Disorders of acid base balance

28. Disorders of acid base balance

29. Thank you