Intracellular fluid

Intracellular fluid (ICF) is the fluid enclosed in the cells of the body. It is the principal component of the cytoplasm, which includes the organelles and cytosol. The ICF makes up about 60% of the total water in the human body, and in an average adult male human, the ICF accounts for about 25 liters of fluid. This fluid is in constant motion, as it is used in both the synthesis and the transport of molecules throughout the cell.

Composition

The intracellular fluid is primarily composed of water, electrolytes, and proteins. The most abundant ions are potassium and phosphate. The pH of the intracellular fluid is approximately 7.0, which is slightly acidic. This is due to the high concentration of proteins and other organic molecules.

Function

The main function of the intracellular fluid is to maintain the shape and structure of the cell. It also serves as a medium for the transport of molecules and ions within the cell. The intracellular fluid also plays a crucial role in maintaining the cell's internal environment and in the transmission of signals within the cell.

Regulation

The composition of the intracellular fluid is tightly regulated by the cell. This is achieved through a variety of mechanisms, including active transport, passive diffusion, and osmosis. The cell membrane is selectively permeable, allowing certain molecules and ions to pass through while blocking others.

Clinical significance

Changes in the composition of the intracellular fluid can have significant effects on the function of the cell. For example, a decrease in the concentration of potassium ions in the intracellular fluid can lead to cell depolarization, which can result in muscle weakness or paralysis. Similarly, changes in the pH of the intracellular fluid can affect the function of enzymes and other proteins within the cell.

See also

• Extracellular fluid
• Cell membrane
• Osmosis
• Active transport
• Passive diffusion

References

Intracellular fluid Resources
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