Body fluids, bodily fluids, or biofluids are liquids within the human body. In lean healthy adult men, the total body water is about 60% (60–67%) of the total body weight; it is usually slightly lower in women (52-55%). The exact percentage of fluid relative to body weight is inversely proportional to the percentage of body fat. A lean 70 kg (160 pound) man, for example, has about 42 (42–47) liters of water in his body.

1. HAEMATOPOIETIC
SYSTEM
(BODY FLUIDS & BLOOD)
The haematopoietic system is the system in the
body involved in the creation/production of the
cells of blood.

2. BODY FLUIDS
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, because
the proportions of the body given over to each organ and to
muscles, fat, bone, and other tissues change from infancy to
adulthood

3. Water Content of the Body’s
Organs and Tissues
Water content varies in different body organs and tissues, from as little as 8
percent in the teeth to as much as 85 percent in the brain.

4. Fluid Compartments in the
Human Body
The intracellular fluid (ICF) is the
fluid within cells.
The interstitial fluid (IF) is part of
the extracellular fluid (ECF)
between the cells.
Blood plasma is the second part
of the ECF.

5. Total Body Fluid in Each of the
Body’s Fluid Compartment
Most of the water in the body is
intracellular fluid.
The second largest volume is
the interstitial fluid, which
surrounds cells that are not
blood cells.

6. Difference between intracellular and
extracellular fluid

8. Ions present in body fluids