it's very nice to me for preparing this presentation for medical student who interesting to understanding the value of body fluid and how it's regulated

1. Topic 1. Body fluid &
Water Homeostasis:

2. Body fluids: are liquids originating from inside the bodies of
living humans and plays a vital role within our bodies
• SIGNIFICANCE or (importance) OF BODY FLUIDS:
1. Homeostasis.
2. Transport mechanism.
3. Metabolic reactions.
4. Texture (shape) of tissues.
5. Temperature regulation.
• Total-body water is the sum of the ICF and
ECF volumes.

4. Formula of body fluid:
• Total Body Water “TBW” = weight ‘Kg’ X 0.6
(male) or 0.5 (female) or 0.8 (infant).
1- Intracellular fluid “ICF” {2/3 ~ 0.66} = TBW X
0.66.
2- Extracellular fluid “ECF” {1/3 ~ 0.33} = TBW X
0.33.
A) Interstitial fluid “IF” {3/4 ~ 0.75} = ECF X 0.75.
B) Plasma {1/4 ~ 0.25} = ECF X 0.25.

7. BODY FLUID COMPARTMENTS:
• The percentage of fluid depends on age, gender, and degree
of obesity.

8. COMPOSITION OF BODY FLUIDS:
BODY FLUID:
I. Water II. Solid
„
A) ORGANIC SUBSTANCES:
1. Glucose.
2. Amino acids and other
proteins.
3. Fatty acids and other
lipids.
4. Hormones.
5. Enzymes.
„
B) INORGANIC SUBSTANCES:
1. Sodium.
2. Potassium.
3. Calcium.
4. Magnesium.
5. Chloride.
6. Bicarbonate.
7. Phosphate.
8. Sulfate.

10. OSMOSIS:
• Osmosis is the flow of water across a
semipermeable membrane.
• Water moves from low concentration to high
concentration.
• The difference in solute concentration creates an
osmotic pressure difference across the
membrane and that pressure difference is the
driving force for osmotic water flow.
• Osmotic Pressure: the amount of pressure
required to stop osmosis.
• Rate of osmosis: is the rate of diffusion of water.

12. Water transportation:
• Water transport is driven by osmotic and
hydrostatic pressure differences across
membranes.
• No H2O pumps have ever been described.
• The plasma membranes of many types of cells
have specialized H2O channels—the
aquaporins “AQPs”—that serve as passive
conduits for H2O transport.

13. Types of Osmosis:
1. Endosmosis: Movement of
water into the cell.
2. Exosmosis: Movement of
water out of the cell.

14. CONCENTRATION OF BODY
FLUIDS:
• Concentration of body fluids is expressed in
three ways:
1. Osmolality
2. Osmolarity
3. Tonicity.

15. 1- OSMOLALITY:
• The number of particles (osmoles) per
kilogram of solution (osmoles/kg H2O).
2- OSMOLARITY:
• The number of particles (osmoles) per liter of
solution (osmoles/LH2O).

17. Mole and Osmole
• Mole (mol): is the molecular weight of a
substance in gram.
• Osmole (Osm): is the expression of amount of
osmotically active particles.

19. 3- TONICITY:
• Tonicity: is the measure of effective osmolality.
• Example:
• Small molecules like urea and alcohol – cross
membrane very rapidly, but does not influence
water movement so these are called “ ineffective
osmoles ”
• Large molecules like Sodium and Glucose – cross
membrane very slowly, but influence water
movement so these are called “ effective osmoles ”

21. Intracellular water regulation

23. • Fluid intake and output are balanced
during steady-state conditions.
Balance b/w Fluid Intake & Fluid Loss:
DAILY INTAKE OF WATER:
1. It is ingested in the form of
liquids or water in food
(2L).
2. It is synthesized in the
body by oxidation of
carbohydrates, adding
about 200 ml/day.
DAILY LOSS OF BODY WATER:
1. Insensible Water Loss
(Skin, Lungs).
2. Fluid Loss in Sweat.
3. Water Loss in Feces.
4. Water Loss by the
Kidneys (urine).

26. • The four primary forces that determine whether
fluid will move out of the blood into the
interstitial fluid or in the opposite direction.
1. The capillary pressure (Pc).
2. The interstitial fluid pressure (Pif).
3. The capillary plasma colloid osmotic pressure
(Πp).
4. The interstitial fluid colloid osmotic pressure
(Πif).

27. .
(from capillary to ECF).
(from ECF to capillary)
(from ECF to capillary).
(from capillary to ECF).
FILTRATION
FILTRATION
ABSORPTION
ABSORPTION

29. • Some of the different factors that can
cause extracellular and intracellular
volumes to change markedly are:
• Factors causes excess of
water in the body:
1. Excess ingestion.
2. Renal retention of water.
3. Intravenous infusion of
different types of
solutions.
• Factors causes loss of water
in the body:
1. Dehydration.
2. Loss of large amounts of
fluid from the
gastrointestinal tract.
3. Loss of abnormal amounts
of fluid by sweating or
through the kidneys.

30. • Is the presence of excess fluid in the body tissues.
• In most instances, edema occurs mainly in the
extracellular fluid compartment, but it can involve
intracellular fluid.
EDEMA

31. Causes of Extracellular Edema:
1. Increased capillary Pressure.
2. Increased Capillary permeability.
3. Decreased plasma proteins.
4. Blockage lymph return.

32. 1. Increased Capillary
Hydrostatic Pressure 3. Decreased Capillary
Oncotic Pressure
4. Blockage lymphatic
vessels

34. Causes of Intracellular Edema:
1. Hyponatremia.
2. Lack of nutrition to the cell.
3. Depressed metabolism.
4. Inflammation.

35. 1. Hyponatremia
4. Inflammation
3. Depressed cell metabolism
2. Lack of nutrition.

36. MAINTENANCE OF WATER BALANCE:
• Body has several mechanisms which work
together to maintain the water balance.
• The important mechanisms involve:
1. Hypothalamus.
2. Kidneys.
Thirst & hormone secretion Concentrated and diluted
urine
a) Osmolarity.
b) Blood volume.
c) Blood pressure.

38. Regulation of blood volume:

39. Regulation of blood volume:
Increased Plasma Volume
Increased venous return, atria, and arterial pressure.
Secretion of atrial
natriuretic peptide
(ANP) by atrial muscle
Decrease secretion of
ADH, and Aldestrone.
Excretion of Nacl and water.
Decreased plasma volume

40. Regulation of blood pressure:

41. Regulation of blood pressure:

42. Regulation of blood osmolarity:
Decreased ECF osmolarity
Suppression of thirst in the
hypothalamus
Suppression of ADH
Secretion of diluted urine
Stimulation of kidney and
adrenal cortex
Reabsorption of Na+
Increased ECF osmolarity
RAAS mechanism

43. Regulation of blood osmolarity: