Name the body fluid compartments, noting their locations and the approximate fluid volume in each.
The correct answer and explanation is :
The body fluid compartments are generally divided into two main categories: intracellular fluid (ICF) and extracellular fluid (ECF). Each of these compartments has further subdivisions that help in understanding the distribution of body fluids.
1. Intracellular Fluid (ICF)
- Location: Found within the cells of the body.
- Volume: Approximately 25 liters (about 40% of total body weight). Intracellular fluid refers to the fluid contained within the membranes of cells. This is the largest compartment of fluid in the body, making up about two-thirds of total body water. The ICF is essential for the functioning of the cells, providing a medium for metabolic reactions and the transport of ions, proteins, and nutrients. It contains high concentrations of potassium (K+) and phosphate ions.
2. Extracellular Fluid (ECF)
- Location: Found outside the cells, in various spaces between the cells and within blood vessels.
- Volume: Approximately 15 liters (about 20% of total body weight). The extracellular fluid can be divided into several components:
- Interstitial Fluid: This is the fluid that surrounds the cells in tissues. It constitutes about 12 liters (about 80% of the ECF) and acts as the medium through which nutrients, gases, and waste products move between blood and cells. It contains a high concentration of sodium (Na+) and chloride (Cl-) ions.
- Plasma (Intravascular Fluid): Plasma is the fluid portion of blood that circulates within the blood vessels. It accounts for about 3 liters of the ECF and contains plasma proteins such as albumin and fibrinogen. Plasma is crucial for the transport of blood cells, nutrients, hormones, and waste products.
- Transcellular Fluid: This is a small compartment, constituting about 1 liter of fluid. It includes cerebrospinal fluid, synovial fluid, and fluid in the eyes and gastrointestinal tract.
Summary of Fluid Volumes:
- Intracellular Fluid (ICF): 25 liters (about 40% of body weight)
- Extracellular Fluid (ECF): 15 liters (about 20% of body weight)
- Interstitial Fluid: 12 liters
- Plasma: 3 liters
- Transcellular Fluid: 1 liter
In total, about 60% of the body weight in adults is water, and these compartments maintain the balance of fluids and electrolytes necessary for normal physiological functions.