Body Fluids Analysis

1. By
Dr KHALED ALGARIRI
September 2020

2. INTRODUCTION
The chemical reactions of life take place in aqueous solutions.
The dissolved substances in a solution are called solutes. In the
human body, solutes vary in different parts of the body, but may
include proteins—including those that transport lipids,
carbohydrates, and, very importantly, electrolytes.

3. Importance of body fluids?????

4.  In average young adult male:
% of body weightBody composition
18%Protein, & related substances
15%Fat
7%Mineral
60%Water
BODY COMPOSITION

5. BODY WATER CONTENT
Human beings are mostly water, ranging from about 75 percent of
body mass in infants to about 50–60 percent in adult men and
women, to as low as 45 percent in old age. The percent of body water
changes with development,.

6. The percent of body water changes with
development, because the proportions of the
body given over to each organ and to
muscles, fat, bone, and other tissues change
from infancy to adulthood .Brain and
kidneys have the highest proportions of
water,. In contrast, teeth have the lowest
proportion of water, at 8–10 percent.
BODY WATER CONTENT

7. BODY FLUIDS
 Water content in body is divided into 2 compartments:
1. Extracellular fluid (ECF)
- fluid outside the cells.
 1/3 volume of fluids in body ( 33% of total body water
TBW).
- contains ions & nutrients needed for cellular life.
2. Intracellular fluid (ICF):
- fluid inside the cells.
 2/3 volume of fluids in body ( 67% of total body water).

8. VOLUME OF BODY FLUIDS IN 70 kg MAN
TOTAL VOLUME
42 L
INTRA CELLUAR FLUID
28 L(ROUGHLY 2/3 OF TBW)
EXTRA CELLULAR FLUID
14 L(ROUGHLY 1/3 OF TBW)
PLASMA
4 L (ROUGHLY ¼ OF ECF)

9. Fluid Compartments
 60% of body weight
Extracellular fluid
( 1/3)
 33% of TBW
 20% of body wt
Intracellular fluid
( 2/3)
 67% of TBW
 40% of body wt
Interstitial fluid
75% of ECF
 15% of body wt
Plasma
 25% of ECF
 5% of body wt
Transcellular fluid
CSF
Intraocular
Pleural
Peritoneal
Pericardial
Synovial
Digestive secretions

10. BODY FLUID COMPARTMENTS

11. COMPOSITION OF BODY FLUIDS
 Water is the universal solvent
 Solutes are broadly classified into:
 (a) Electrolytes – inorganic salts, all acids and bases, and some proteins
 (b) Nonelectrolytes – examples include glucose, lipids, creatinine, and urea
 Osmosis: Is the movement of water across a semipermeable membrane
from an area of lower concentration to one that has higher concentration to
make it diluted.
 Electrolytes have greater osmotic power than nonelectrolytes
 Water moves according to osmotic gradients

12. Extracellular and Intracellular Fluids
 Each fluid compartment of the body has a distinctive pattern of electrolytes
 Extracellular fluids are similar
 Sodium is the chief cation (+)
 Chloride is the major anion (-)
 Intracellular fluids have low sodium and chloride
 Potassium is the chief cation
 Phosphate is the chief anion
 Sodium and potassium concentrations in extra- and intracellular fluids are
nearly opposites
 This reflects the activity of cellular ATP-dependent sodium-potassium pumps
 Electrolytes determine the chemical and physical reactions of fluids

13. FUNCTIONS OF WATER CONTENT IN THE BODY
Water in Temperature Regulation
• Water helps maintain body temperature. When water vaporizes off the skin, it takes
large quantities of heat with it. This process cools the body temperature down.
• Because water has a high heat capacity it can absorb and release large quantities of
heat before significantly changing temperature. Because our bodies are composed of
50-70% water, that large percentage of water holds heat in the body and helps prevent
fluctuation in body temperature.
Water in Cushioning and Lubricating
• Water acts as a protective cushion in amniotic fluid and cerebrospinal fluid.
• Water acts as a lubricant in the serous fluids, joints, and gastrointestinal tract.

14. Water as a Reactant
• Water is the reactant for hydrolysis reactions that occur in the body.
• With the help of an enzyme, water molecules are added to the bonds between the
glucose units in the starch, hydrolyzing the starch to glucose.
• Water can also be formed during some chemical reactions in the body, such as the
reactions that produce metabolic water.
Water as a Solvent
• Water acts as a solvent to dissolve molecules and ions in the body.
• For example, if you eat a salty pretzel, the water in your saliva will dissolve the salt..
• Except for the salts deposited in bone and teeth, most other ions in the body are
dissolved because of water's ability to act as a solvent.
• Water within cells is an important solvent. It dissolves many of the proteins and other
solutes.

15. Water in Transport
• We are now looking at a blood vessel. Because of water's ability to
dissolve ions and molecules within the body fluids, water functions as a
medium for the delivery of nutrients and the removal of wastes from the
cells through the plasma.

16. WATER BALANCE
 To remain properly hydrated, water intake must equal water output
 Water intake sources
 Ingested fluid (60%) and solid food (30%)
 Metabolic water or water of oxidation (10%)
 Water output:
 Urine (60%) and feces (4%)
 Insensible losses (water loss via evaporation from the skin and respiration) (28%),
sweat (8%)
 Increases in plasma osmolality (the concentration of a solution expressed as the
total number of solute particles per kilogram) trigger thirst and release of
antidiuretic hormone (ADH)

17. WATER BALANCE

18. The endocrine system plays important role in
water homestasis by
 Aldosterone
 Antidiuretic Hormone ADH
 Atrial natriuretic peptide (ANP)

19. Aldosterone, a steroid hormone secreted by the adrenal
glands. Aldosterone serves as the principal regulator of
the salt and water balance of the body and thus is
categorized as a mineralocorticoid. It also has a small
effect on the metabolism of fats, carbohydrates, and
proteins.

20. Antidiuretic Hormone ADH
is also called vasopressin. It’s a hormone made by the
hypothalamus in the brain and stored in the posterior
pituitary gland. It tells your kidneys how much water to
conserve.
ADH constantly regulates and balances the amount of water in
the blood. Higher water concentration increases the volume
and pressure of your blood. Osmotic sensors and baroreceptors
work with ADH to maintain water metabolism

21. It is a hormone that promotes both fluid and sodium loss by the kidneys.
The name natriuretic actually means “salt excreting.” ANP release from
the atria is stimulated when blood volume and pressure are elevated.
ANP has three major effects: 1) it decreases aldosterone release,
resulting in a decrease in sodium reabsorption and increased sodium loss
in the urine; 2) it decreases ADH release, which decreases water
reabsorption and increases water loss to lower blood volume and
pressure; and 3) it decreases thirst.
Atrial natriuretic peptide (ANP)

22. FUNCTIONS OF THE KIDNEY
Filtration of waste products from the blood.
Tubular reabsorption of useful substances from the
filtrate.
Kidneys produce urine that contains metabolic waste
products, including the nitrogenous compounds urea
and uric acid, excess ions and some drugs.
Maintaining normal blood pressure by balancing
electrolytes in the blood.

23. KIDNEY AND BODY FLUIDS
99 % of water& Na is reabsorpred by tubules to maintain osmotic balance.
Kidney regulate volume of the body fluid by reabsorbing water and Na.
If more Na is excreted, this leads to water excretion and dehydration.
If low Na is excreted, this leads to low water excretion and fluid retention
(hypervolemia), thus increase BP
 When low BP & low blood flow to kidney, kidney release renin which
convert angiotensinogen to angiotensin1, lung convert angiotensin I to
angiotension II, Leads to vasoconstriction, increase BP, increase renal
perfusion.

24.  Activates Adrenal cortex to releases Aldosterone hormone
increase renal reabsorption of water and Na, thus increase BP,
increase renal perfusion.
 Aldosterone activate pituitary gland to release Antiduitretics
hormones ( ADH) which stop diuretics, this lead to low urine
output, and high Na & water retention thus increase BP,
increase renal perfusion
KIDNEY AND BODY FLUIDS….cntn

25. REGULATION OF ECF VOLUME

26. HORMONAL REGULATION OF BLOOD
OSMOLALITY

27. REGULATION OF WATER INTAKE