Body-Fluid Compartments BBCCT 115

 Body-Fluid Compartments

Cells of the different organs system need a constant supply of oxygen, nutrient, and energy for proper functioning of the body which depend upon the exchange of ions and nutrients between the cells and blood vessels, and also among the cells. in due course of biological evolution multicellular animals have developed the body fluids which helps in the movement of molecules and ions within the body.

This ensures that the body cell have a constant steady state in response to any environmental change.

The fluids are divided into two major fluid compartments based on their location in the body.

1. Intracellular fluid is present within the cells and thus is enclosed by the cell membrane.

2.Extracellular fluids (plasma and interstitial fluid) is present outside the cells; within blood vessels or in the space in between the cell.

1.. Intracellular fluids (ICF)

the fluids present inside the body cells is called intracellular fluids(ICF). it is the principal component of cytoplasm/cytosol and is enclosed by the cell membrane. cytoplasm is the entire aqueous content of the cells within the plasma membrane excluding the content of nucleus. on the other hand, cytosol is the intracellular fluid which does not include the contents within the membrane-bound organelles (mitochondria and Golgi body etc. 

(ICF) makes approximately 60% of the total water in the human body which amount to roughly 25 liters in an average -sized and healthy adult male. most of the biochemical function take place in water medium. the cells regulate the water content and keep constant by exchanging the material with extracellular fluids. Body cells cannot perform their normal function, if volume of water in a cells is too low or too high . in fact , if a cell has excess water, it may burst and get destroyed.

1.2 Extracellular fluids(ECF)

The term extracellular fluids denotes all body fluids that are present outside the cells.it account for approximately 1/3rd of the total body water. The ECF serves as an "internal sea" from which the cells take up oxygen and nutrients; and in turn ,discharge metabolic waste product into it. it has optimum

 pH 7.4  which is required for normal functions of the cells.

The extracellular fluids comprises three kinds of fluids ;the bloods plasma, the interstitial fluids (IF) that surrounds all body cells except blood cells and transcellular fluids which is water -based fluids released by the special cells of body.

(i)plasma 

Is an aqueous fluids of the blood present inside the vascular system. it is made up of mostly water (93% by volume) that contains many dissolved proteins i..e fibrinogen, globulins and albumins), hormones, glucose clotting factors, minerals ions sodium, calcium  dioxide. it accounts 25% of the total ECF. it carries blood cells , nutrients and a range of materials through blood vessels to all cells and tissues of the body.

(ii) Interstitial fluids (IF)

Is the extracellular fluids that travels amid blood capillaries and body cells. it is outside fluids of the visceral system. the interstitial fluids is constantly released from the blood plasma through the capillary walls so that the gases ,electrolytes ,proteins, nutrients and waste product can move between cells and the capillaries. cell are separated from the if by semipermeable plasma membrane that controls the passage of a range of material between the IF and interior of the cells. 

(iii)Transcellular fluids

Is the small portion of the body water found within the epithelial- lined space. it accounts for about 1.5% body weight. it includes cerebrospinal fluids in the brain and spinal cord, synovial fluids in joints, the gastrointestinal fluid in the stomach ,aqueous humor in the eyes, the pericardial fluids in the cardiac sac, peritoneal fluid in the peritoneal cavity and pleural fluids in pleural cavities,