Intracellular Fluids vs. Extracellular Fluids

Intracellular fluid is the liquid located inside the cells, while extracellular fluid surrounds the cells. The intracellular fluid contains proteins and amino acids and has a concentration gradient whereas extracellular fluid presents with more ions.

What are Intracellular Fluids?

Intracellular fluid is also known as the Cytosol or the cytoplasmic matrix, which is a liquid with many properties to ensure the cellular processes are taken place well without any hassle. Intracellular fluid is limited only to the interior of the cell, and the cell membrane is the boundary of the cytosol.

The membranes of organelles separate cytosol from the matrices of organelles. Many of the metabolic pathways take place in the intracellular fluid, in both prokaryotes and eukaryotes. However, eukaryotic metabolic pathways are more common inside organelles than in cytosol.

The composition of the intracellular fluid is important to know, as it contains mostly water with some ions such as sodium, potassium, chloride, magnesium, and some others. Due to the presence of amino acids, water-soluble proteins, and other molecules, the cytosol has many properties.

Despite the fact that there is no membrane to localize the contents of cytosol, there are some confinements of the intracellular fluid that takes place through concentration gradients, protein complexes, cytoskeletal sieving, and protein compartments.

The intracellular fluid does not perform a specific duty, but it aids in many functions including signal transduction within organelles, provide a place for cytokinesis and protein synthesis, transportation of molecules, and many others.

What are Extracellular Fluids?

As the term extracellular means, it is the fluid found outside the cells. In other words, extracellular fluid is the body fluid in which the cells and tissues are facilitated. The membrane-bound cells are provided with the required nutrients and other supplements through the extracellular fluids. It mainly consists of sodium, potassium, calcium, chlorides, and bicarbonates.

However, the presence of proteins is very rare in the extracellular fluid. The pH is usually maintained around 7.4, and the fluid has the buffering capacity to a considerable extent, as well. The presence of glucose in the extracellular fluid is important in regulating the homeostasis with cells, and the usual concentration of glucose in humans is five mill molars (5 mM).

Mainly, there are two major types of extracellular fluids known as interstitial fluid and blood plasma. All those discussed factors are the main properties and constituents of interstitial fluids, which is roughly about 12 liters in a fully-grown human. The total volume of blood plasma is about three liters in a human.

Key Differences between Intracellular Fluids and Extracellular Fluids

  1. Intracellular fluid is fluid within the cell whereas extracellular fluid is a fluid located outside the cell.
  2. Intracellular fluid is composed of water and dissolved proteins and solutes whereas extracellular fluid is composed of blood plasma, interstitial fluid, lymph and transcellular fluid.
  3. The presence of proteins and amino acids is a feature of intracellular fluid whereas all these are absent in extracellular fluid.
  4. The intracellular fluid contains fewer ions whereas extracellular fluid contains more ions.
  5. The intracellular fluid contains organelles to break down glucose present in it to produce energy but the extracellular fluid does not contain any organelles.
  6. Intracellular fluid is of only one type whereas extracellular fluid is of two main types.

Video Explanation

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