BODY FLUIDS

BODY FLUID
JAI NARAIN VYAS UNIVERSITY, JODHPUR
ASSISTANT PROFESSOR:- ASHWIN SINGH
CHOUHAN
DEPARTMENT:- PHARMACOLOGY
E-mail:- anshukavya1993@gmail.com

BODY FLUIDS
Blood and lymph are the two most important body fluids
in the human body. Blood comprises of plasma, white
blood cells, red blood cells, and platelets.
Lymph is a colourless fluid that circulates inside the
lymphatic vessels.
The body fluids and circulation of these body fluids is
described below in complete detail.
JNVU PHARMACY, JODHPUR

FUNCTIONS OF BODY FLUIDS
The important functions of body fluids include:
The body fluids facilitate the transportation of oxygen
and nutrients throughout the body and remove the waste
from the body.
They help in regulating the body temperature.
They maintain an efficient metabolism of the body.

BODY FLUIDS
Water content of the body is divided into:
1.Intracellular compartment (67%) - Inside the cell
2.Extracellular compartment (33%) - Outside the cell

Composition of Body Fluids
The composition of the body fluids is explained below
Body Fluids Composition
Intracellular Body Fluids 70% water, ions, and
molecules
Extracellular Body Fluids Cations and Anions
Transcellular Fluid Electrolytes such as sodium,
bicarbonate and chloride
ions.

TYPES OF BODY FLUIDS
The different types of body fluids include:
Blood
The main components of blood include:
Plasma: Plasma is the liquid component of blood. It is
a thick fluid containing 55% blood, 90% water, and 8%
proteins. Albumin is the major protein in plasma. Other
proteins include immunoglobulins and clotting factors.
Red Blood Cells: 40% of the blood contains red blood
cells. RBCs contain protein haemoglobin that gives the
red colour to the blood.

White Blood Cells: The white blood cells are very few in
number. The WBC to RBC ratio is 1:600. They mainly
protect the body against infections. Many WBCs cross the
walls of the vessels and penetrate other tissues.
Platelets: These are fewer in number than the red blood
cells. The platelets help in the clotting of blood at the site
of a wound.
Lymph
Lymph is a colourless fluid present in the interstitial
tissues. It circulates throughout the lymphatic system.
It can be defined as blood without the RBCs.
The exchange of nutrients, hormones, and gases occurs
through this fluid.
It consists of lymphocytes that play a major function in
the immune responses of the body.

FLUID COMPARTMENTS
There are two main fluid compartments water
occupies in the body. About two-thirds is in
the intracellular fluid compartment (ICF). The
intracellular fluid is the fluid within the cells of the body.
The remaining one-third of body water is outside cells,
in the extracellular fluid compartment (ECF). The ECF
is the body’s internal environment and the cells external
environment.
In the image above, the ECF compartment is divisible in
two compartments: (1) Plasma, the fluid portion of
blood, and (2) interstitial fluid (IF), the fluid in the
spaces between tissue cells.
It has been known that human plasma has a significantly
longer shelf life than blood which is why it can be more
sought after for those that need it as part of their
treatment.

1. Intracellular Fluid (ICF)
Comprises, 2/3 of the body water.
If body has 60% water, ICF is about 40% of your weight.
The ICF is primarily a solution of potassium and organic
anions, proteins etc.
The cell membranes and cellular metabolism control the
constituents of this ICF.
2.Extracellular compartment (ECF)
It is the remaining 1/3 of your body's water.
ECF is about 20% of the body weight.
The ECF is primarily a NaCl and NaHCO3 solution.
The ECF is further subdivided into three sub-compartments:
Interstitial Fluid (ISF).
Plasma.
Transcellular fluid

A.Interstitial Fluid (ISF)
Interstitial Fluid (ISF) surrounds the cells, but does not
circulate.
It is the main component of the extracellular fluid
It comprises about 3/4 of the ECF.
Interstitial fluid is found in the interstitial spaces, also
known as the tissue spaces.
Composition of interstitial fluid:
 Water solvent amino acids
 Sugars
 Fatty acids
 Coenzymes
 Hormones
Neurotransmitters
Salts
Waste products from the cells.
Lymph is considered a part of
the interstitial fluid

Function of interstitial fluid
Intercellular communication.
Interstitial fluid bathes the cells of the tissues.
Removal of metabolic waste.
B. Plasma:
It is the yellow liquid component of blood in which the blood
cells in whole blood are normally suspended
 55% of the total blood volume.
 It is the intravascular fluid part of extracellular fluid (all
body fluid outside of cells)
 It makes up about 1/4 of the ECF.
Composition of plasma
Water (90% by volume)
Dissolved proteins
Glucose
Carbon dioxide.
Clotting factors
Mineral ions
Hormones

Function of plasma
Plasma is the main medium for excretory product
transportation.
Blood serum is blood plasma without fibrinogen or the
other clotting factors (i.e., whole blood minus both the
cells and the clotting factors).
Examples
 Cerebrospinal fluid
 Ocular fluid (Aqueous
humor)
C. Transcellular fluid
Transcellular fluid is the portion of total body water
contained within epithelial lined spaces.
Smallest compartment.
It is about 2.5% of the total body water.
Joint fluid (Synovial
fluid)
Urine

Composition of transcellular fluid:
1.Cerebrospinal fluid:
The CSF is mainly produced by the choroid plexus.
The entire nervous system contains between 80-150 ml of
CSF.
It is a clear colorless liquid that contains White blood cells,
glucose, protein,
lactic acid, urea, cations (Na+
, K+
, Ca+
etc) and anions
(Cl-
, and HCO3 ).
2.Ocular fluid (Aqueous humor):
The aqueous humor is a transparent, gelatinous fluid
similar to plasma.
It is located in the anterior and posterior chambers of the
eye, the space between the lens and the cornea.
It contains Amino acids (transported by cilliary muscles),
98% water, Electrolytes, Ascorbic acid, Glutathione

3.Joint fluid (Synovial fluid):
Synovial fluid is clear, pale yellow, viscid, and does not clot.
The principal role of synovial fluid is to reduce friction
between the articular cartilage of synovial joints during
movement.
It contains Normal 3–4 mg/ml hyaluronic acid, a polymer of
disaccharides,WBC, RBC and proteins
4.Urine:
Urine is a typically sterile liquid by product of the body
secreted by the kidneys through a process called urination and
excreted through the urethra.
It contains 95% water, Organic solutes like urea, creatinine,
uric acid, and trace amounts of enzymes, carbohydrates,
hormones, fatty acids, pigments, and mucins, and inorganic
ions such as sodium (Na+
), potassium (K+
),chloride (Cl),
magnesium(Mg2+
), calcium(Ca2+
), ammonium(NH4 ),sulfates
(SO4 ), and phosphates (e.g., PO4 ).

BODY WATER CONTENT
Factors which determine the overall water weight of a
human being include sex, age, mass and body fat
percentage. Infants, with their low bone mass and low
body fat, are 73% water! Due to the high concentration
of water, an infants skin appears “dewy” and soft. Total
body water declines after infancy, and by the team one
reaches old age, total body water is only about 45%.
The average young man is around 60% water, while a
healthy young woman is about 50%. This is because
women typically have less skeletal muscle and more fat
than males. Adipose (fat) tissue is the least hydrated
tissue in the body (20% hydrated), even bone contains
more water than fat. In contrast, skeletal muscle contains
75% water. So, the more muscles one has, the higher the
total body water % will be.

COMPOSITION OF BODY FLUIDS
Electrolytes and Nonelectrolytes
Nonelectrolytes have bonds (usually covalent bonds)
that prevent them from disassociating in a solution.
Because of this, no electrically charged species are
created when nonelectrolytes dissolve in water. Most
nonelectrolytes are organic molecules — lipids, glucose,
urea, creatinine, for example.
In contrast, electrolytes are chemical compounds that
do disassociate into ions in water. Since ions are charged
particles, they can conduct an electrical current — that’s
why they’re called electrolytes! For the most part,
electrolytes include organic salts, some proteins, and
both organic and inorganic acids and bases.

Electrolytes have much greater osmotic power than
nonelectrolytes because each electrolyte molecule
disassociates into at least two ions. For instance, a
molecule of sodium chloride (NaCl) contributes twice as
many solute particles as glucose, and a molecule of
magnesium chloride (MgCl2) contributes three times as
many.
Regardless of the type of solute particle, water always
moves according to osmotic gradients — from an area of
lesser osmolarity to an area of greater osmolarity. For
this reason, electrolytes have the greatest ability to cause
fluid shifts.

Electrolyte concentrations of body fluids are usually
expressed in milliequivalents per liter (mEq/L), a measure
of the number of electrical charges in one liter of solution.
We can compute the concentration of any solution using
the following equation: mEq/L = ion concentration (mg/L)
divided by the atomic weight of the ion (mg/mmol) X the
number of electrical charges on the ion.
For instance to calculate the mEq/L of sodium we would
determine the normal concentration of the ion in plasma,
look up its atomic weight in the periodic table and plug
the values into the equation: Na+ (sodium) = 3300 mg/L
divided by 23 mg/mmol X 1 = 143 mEq/L. We could do
the same thing for calcium: Ca2+ = 100 mg/L divided by
40 mg/mmol X 2 = 5 mEq/L.

Comparison of Extracellular and Intracellular Fluids
If you look at the bar graph above you can see that
each fluid compartment has a distinctive pattern of
electrolytes.
Beside the relatively high protein content in plasma, the
extracellular fluids are very similar.
The chief cation is sodium and the major anion is
chloride. However, plasma contains fewer chloride
molecules than interstitial fluid, because non-penetrating
protein molecules are usually anions and plasma is
electrically neutral.
In contrast to extracellular fluid, intracellular fluid
contains only small amounts of sodium and chloride. It’s
most abundant cation is potassium, and its major anion is
hydrogen phosphate. In the graph above, notice that
sodium and potassium ion concentrations in ECF and ICF
are nearly opposite.

The distribution of these ions on the two sides of
cellular membranes reflects the activity of cellular ATP-
dependant sodium-potassium pumps, which keep
intracellular sodium concentrations low and potassium
concentrations high.
Renal mechanisms can enforce ion distribution by
secreting potassium into the filtrate as sodium is
reabsorbed from the filtrate.
Electrolytes are the most abundant solutes in body
fluids and determine most of their chemical and physical
reactions, but they do not constitute the bulk of dissolved
solutes in these fluids.
Proteins and nonelectrolytes (phospholipids, cholesterol,
and triglyceride) found in the ECF are large molecules.
They account for around 90% of the mass of dissolved
solutes in plasma and 60% in the IF, and 97% in the ICF.

FLUID MOVEMENT AMONG COMPARTMENTS
Osmotic and Hydrostatic pressures regulate the
continuous exchange and mixing of body fluids. Although
water moves freely between the compartments along
osmotic gradients, solutes are unequally distributed
because of their size, electrical charge, or dependence on
transport proteins. The image at the top of this article
summarizes the exchanges of gases, solutes, and water
between the three fluid compartments within the body. In
general, substances must pass through both the plasma
and interstitial fluid to reach the intracellular fluid. In the
lungs, gastrointestinal tract, and kidneys, exchanges
between the outside world and the plasma o ccur
continuously.

These exchanges alter plasma composition and volume, with
plasma serving as the “highway” for delivering substances throughout
the body.
Compensating adjustments between the plasma and the other two
fluid compartments follow quickly so that balance is restored.
Let’s review the movement of water and solutes across the
boundaries between these compartments:

Exchanges between plasma and interstitial fluid
occur across capillary walls.
The hydrostatic pressure of blood forces nearly protein-
free plasma out of the blood into the interstitial space.
The filtered fluid is then almost completely reabsorbed
into the bloodstream in response to the colloid osmotic
pressure of plasma proteins.
Under normal circumstances, lymphatic vessels pick up
the small net leakage that remains behind in the
interstitial space and return it to the blood.

Exchanges between the interstitial fluid and
intracellular fluid occur across plasma membranes.
Exchanges across the plasma membrane depend on its
permeability properties. As a general rule, two-way
osmotic flow of water is substantial. But ion fluxes are
restricted and, in most cases, ions move selectively, by
active transport or through channels. Movements of
nutrients, respiratory gases, and wastes are typically
unidirectional (both ways). For instance, glucose and
oxygen move into the cells and metabolic wastes move
out.
Many factors can change ECF and ICF volumes. Because
water moves freely between compartments, however, the
osmolarities of all body fluids are equal. Increasing the ECF
solute content (mainly sodium chloride) causes osmotic
and volume changes in the ICF — generally, a shift of
water out of cells. Conversely, decreasing ECF osmolarity
causes water to move into the cells. Thus, ECF solute
concentration determines ICF volume.

THANK YOU

BODY FLUIDS

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