Fluid compartments

Fluid compartments

Claude Bernard, who contributed to the understanding of the internal environment.

Fluid compartments are the distinct environments within the body where fluids are contained. These compartments are crucial for maintaining the body's homeostasis and are separated by semipermeable membranes that allow for the selective movement of substances.

Types of fluid compartments

The body is primarily divided into two main fluid compartments:

Intracellular fluid (ICF)

The intracellular fluid compartment is the fluid contained within cells. It accounts for about two-thirds of the total body water in humans. The ICF is rich in potassium and magnesium ions, and it contains a high concentration of proteins and other solutes that are essential for cellular processes.

Extracellular fluid (ECF)

The extracellular fluid compartment is the fluid outside of cells. It makes up about one-third of the total body water and is further divided into:

Interstitial fluid

The interstitial fluid surrounds the cells and provides a medium for the exchange of nutrients and waste products between the blood and cells. It is similar in composition to plasma but contains less protein.

Plasma

Plasma is the liquid component of blood and is contained within the blood vessels. It is rich in proteins, such as albumin, and serves as a transport medium for nutrients, hormones, and waste products.

Transcellular fluid

Transcellular fluid is a small portion of the ECF that is contained within epithelial-lined spaces. Examples include cerebrospinal fluid, synovial fluid, and aqueous humor.

Movement between compartments

The movement of fluids between compartments is governed by osmosis and hydrostatic pressure. The semipermeable membranes that separate these compartments allow for the selective passage of water and solutes, maintaining the balance of electrolytes and other substances.

Importance of fluid balance

Maintaining the proper balance of fluids between compartments is essential for normal physiological function. Disruptions in fluid balance can lead to conditions such as edema, dehydration, and hyponatremia.

Historical perspective

The concept of fluid compartments and the internal environment was significantly advanced by the work of Claude Bernard, a French physiologist. Bernard introduced the idea of the "milieu intérieur," emphasizing the stability of the internal environment as crucial for the survival of organisms.

Related pages

• Homeostasis
• Electrolyte
• Osmoregulation
• Claude Bernard