________________
The Dynamic Balance of
Body Fluids
Regulation of Total Body Fluids
A human body passes through an evolution as it develops. An embryo is 97% water, a newborn infant is 77% and an adult man only about 60 to 65%. Because of more water-free adipose tissues in a woman, water-content is 54%. The composition of the fluid media remains relatively constant. The dynamic equilibrium is maintained by the complex interaction of respiratory, circulatory, digestive, excretory, endocrine and nervous systems. It is one of the most important aspects of homeostasis i.e. optimum internal conditions of health.
There is a high degree of internal organisation-structural differentiation and compartmentalization of the body fluids. About two-thirds of the total body fluid is intracellular (found within the cells). Interstitial fluid which bathes the cells, fluid in the blood and lymph vessels, the cerebrospinal fluid and some other special fluids are extracellular.
Water enters the body through the digestive tract in the form of liquid intake and food consituents. It leaves the body through the lungs, kidneys, the bowel and the skin. To maintain balance, intake must precisely balance the output. If the lost fluid is not replaced promptly, the person would rapidly become dehydrated, placing an increasing strain on the body systems. On the other hand, if fluid intake exceeded output, edema-an excess fluid in the interstitial space-would result, placing a strain on the cardiovascular system. A dynamic equilibrium is maintained by
41
Jain Education International
For Private & Personal Use Only
www.jainelibrary.org
