GENERAL PHYSIOLOGY – BODY FLUIDS

INTRODUCTION

  1. Body fluids.
  2. Cell physiology.
  3. Intercellular connection.
  4. Transport across the cell membrane.

Body fluids :

Example – 70 kg of man.

Body water = 60% of 70kg = 42L.

ICF = 40% of 70kg = 28L( 2/3 of 42L = 28L).

ECF = 20% of 70kg = 14L(1/3 of 42L = 14L).

Plasma = 5% of 70kg = 3.5L(1/4 of 14L = 3.5L).

Inertial fluid = 15% of 70kg = 10.5L or ¾ of ECE = 10.5L.

Diarrhea, vomiting, burn -> ECF loss.

Ionic composition of ECF and ICE:-

Total no. of ions on both side are equal.

Therefore, the osmolality and osmotic pressure are equal on both side.

Major cation in ECF:- Na+>Ca²+.

Major Anion in ECF:- Cl->HCO³-.

Major ion in ECF:- Na+.

Intracellular osmolality is mainly due to – K+.

Extracellular osmolality is mainly due to – Na+.

Major cation in ICF :- K+>Mg²+.

Major anion in ICF :- Po4³->Proteins.

Major ion in ICF :- K+.

Q). Ratio of ECE : ICF Ca²+ = 12000:1.

Q). Normal Na+ level in plasma = 135 – 145 mEq/to (mosm./L).

Normal K+ level in plasma = 3.5-5.0 mEq/ L or (mosm./L).

Normal Cl- level in plasma = 108-110 mEq/L or (mosm./L).

Factors shifting K+ from:

A) ECF to ICF = ↓ECE K+ level -Hypokalemia.

B) ICF to ECF = ↑ ECF K+ level -Hyperkalemia.

ECF→ ICF (K+) All bald person In Home.

1) Insulin.

2) Aldosterone.

3) Alkalosis.

4) Hypo-osmolality ( ↓ ECF osmolality).

 5) B₂ receptor stimulation.

Alkalosis←→Hypokalemia.

Clinically:

1) Insulin can be given to treat hyperkalemia.

2) In DM – Insulin is given → monitor plasma K+ level.

3) Excess of aldosterone lead CONN Syndrome – Hypokalemia.

ICF K+ → ECF (HYPER)

1)Insulin↓ (Diabetes Mellitus).

2) ↓ Aldosterone (Aldosterone deficiency disease).

3) Acidosis (Hyperkalemia).

4) Hyper osmolality (↑ECF osmolality).

5) B₂ blocker.

6) Cell injury/cell lysis.

7) Severe exercise.

Acidosis←→Hyperkalemia.

Major reservoir of;

a) Na+ → ECF (65% of the body Na+ is present in ECF).

b) K+ → Skeletal muscle (3/4 of body K+ is present in skeletal m.).

C) Ca²+, Po4³-, Mg²+ → Bone.

D) Ee²+ – Hemoglobin.

     Ee³+ – Ernestine (liver).

Osmolarity and osmolality:

Osmolarity = No. of osmoles/ Volume of Solution (L).

Osmolality = No. of osmoles / Mass of Solvents (kg).

Osmolality is better to express the concentration of electrolytes/solutes because it is independent of temperature because mass does not change C temperature where as volume changes with temperature.

Therefore the value of osmolality do not change with temperature. Whereas the value of osmolarity vary C temperature.

Normal plasma osmolality = 280-295mosm/kg of water.

= 280-295 mosm /L. of water.

Plasma osmolality is mainly due to Na+.

Isotonic fluid – 

fluid having osmolality equal to that of plasma osmolality.

Eg.- 0.9% Nacl.

5% Dextrose.

10% mannitol.

20% urea.

Hypotonic fluid

fluid having less osmolality than plasma osmolality.

Eg.- <0.9% Nacl.

<5% Dextrose.

< 10% mannitol.

Hypertonic fluid

fluid osmolality > Plasma osmolality.

Eg- >0.9% Nacl.

75% Dextrose.

10% mannitol.

HYPERTONIC FLUID ISOTONIC FLUID HYPOTONIC FLUID
Fluid osmolality > plasma osmolality. Fluid of osmolality= plasma. FO<PO.
Cell shrinks. No change Cell swells

PH:-

-ne log [H+]

↑[H+]=↓Ph.

↓[H+]=↑Ph.

PH scale :-

Where >6 is acidic, 7 is neutral and 8< is alkaline.

PH = 7 = neutral water.

PH < 7 = Acidic water.

PH > 7 = Alkaline water.

If Ph changes by 1, [H+] changes by 10 times.

Eg.-

Ph 7→6, ↑ [H+] by 10 times.

Ph 7→2, ↑ [H+] by 10s.

Ph of some body fluid;

1)Plasma – 7.40 (7.35 – 7.45) Normal PH of plasma is alkaline.

2) Venous Plasma -7.36

3) CSF – 7.30 – 7.33

4) Gastric Juice – 0.8 – 3.0  [most acidic fluid in the body ors least Ph].

5) Gall bladder bile – 7.40

6) Hepatic duct bile -7.8 – 8.6.

7) Pancreatic Juice – 7.8- 8.4.

8) Intestinal Juice- 8.0.

9) Saliva- 6.9 – 8.0.

10) Brunner’s gland secretion (duodenum)- 8.3 – 8.9.

11) RBC (cell) – 7.20.

Most alkaline fluid (Highest PH) – Brunner’s gland secretion.

Most acidic fluid (Lowest Ph) – Gastric juice.

1 Comment.

  1. Soon BodybFluid Part 2 will be online , stay tune, keep sharing nd like the 📝 notes if it helps u ỉn gaining some knowledge ♥️😊.

    Thank you so much

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.