Question

How much water is in an adult human body?

Answer 1

Hint: Water forms the major fluid component in our body. It is the major constituent of the internal environment and plays a major role in various places -
-Homeostasis
-Transport mechanism
-Metabolic reactions
-Maintaining the texture of tissues
-Maintain body temperature

Complete answer:
The human body is made of solids and liquids. The liquid or fluid part forms two-thirds of a component of the body. In females, the water content is less because of more subcutaneous adipose tissue. Also, a thin person has more water content than an obese person. Therefore body characteristics are a major determinant of the water content. The total water content in an ideal human being weighing 70Kgs is almost equal to 40 liters.

Let’s take 40 liters as total water content and divide its values depending upon the two major compartments.
-Intracellular fluid (ICF)- Its volume is 22 L and it forms 55 percent of the total body water.
-Extracellular fluid (ECF)- Its volume is 18 L and it forms 45 percent of the total body water.

ECF is divided into 5 subunits:
-Interstitial fluid and lymph (20%)
-Plasma (7.5%)
-Fluid in bones (7.5%)
-Fluid in dense connective tissues like cartilage (7.5%)
-Transcellular fluid (2.5%) that includes: Cerebrospinal fluid, Intraocular fluid, Digestive juices, Serous fluid – peritoneal fluid, pericardial and intrapleural fluid, Synovial fluid in joints and Fluid in the urinary tract.

Note: Total body water and the volume of different compartments of the body fluid are measured by the indicator dilution method or dye dilution method.
The body has various mechanisms through which maintains the water balance and kidneys play a major role in it.