- Characteristics of intracellular fluid
- Composition of intracellular fluid
- Features
- Osmosis and intracellular fluid
- References
The intracellular fluid is the fluid existing within the cells of multicellular organisms. Therefore, this fluid is stored within the intracellular compartments of the body.
The intracellular compartment is the system that includes all the fluids enclosed in cells by their plasma membranes.
Eukaryotic human cell representation.
When it comes to cellular functions, this type of fluid is often referred to as a cytosol. The cytosol, the organelles, and the molecules within are collectively referred to as the cytoplasm.
The opposite of intracellular fluid is extracellular fluid, which is located outside the cells in the extracellular compartment.
Many enzymes and cellular mechanisms work to transport both products and wastes from intracellular fluid to the extracellular fluid, while bringing new nutrients and solutes to the intracellular fluid.
Unlike extracellular fluid, intracellular fluid has a high concentration of potassium and a low concentration of sodium.
The cytosol is composed primarily of water, dissolved ions, small molecules, and large water-soluble molecules (such as proteins). Its molecules are important to carry out cellular metabolism.
Characteristics of intracellular fluid
Human cells are bathed in fluid, inside the cell and outside the cell. In fact, the water found within cells makes up about 42% of body weight.
The fluid inside cells is called intracellular fluid (IFC) and the fluid outside cells is called extracellular fluid (EFC).
These two fluids are separated by a semipermeable membrane that surrounds the cell. This membrane allows liquid to enter and exit, but at the same time prevents unwanted molecules or materials from entering the cell.
IFC is the main component of the cytoplasm or cytosol. This fluid makes up about 70% of the total water in the human body; a man can have about 25 liters of it.
The volume of this liquid is usually quite stable, since the amount of water found in the cells is regulated by the body.
If the amount of water within a cell falls too low, the cytosol becomes too concentrated in solutes and cannot carry out normal cellular activities. In contrast, if too much water enters a cell, it can explode and be destroyed.
The cytosol is the place where many chemical reactions take place. In prokaryotes is where metabolic reactions occur.
In eukaryotes, it is where the organelles and other cytoplasmic structures are suspended. Since the cytosol contains dissolved ions, it plays an important role in osmoregulation and cell signaling.
It is also involved in the generation of action potentials as occurs in nerve, muscle and endocrine cells.
Composition of intracellular fluid
This liquid contains water, proteins, and dissolved solutes. Solutes are electrolytes, which help keep the body working properly. An electrolyte is an element or compound that, when dissolved in a liquid, decomposes into ions.
There are a large number of electrolytes within the cell, but potassium, magnesium, and phosphate have the highest concentrations.
The concentrations of the other ions in the cytosol or intracellular fluid are very different from the extracellular ones. The cytosol contains large amounts of charged macromolecules, such as proteins or nucleic seizures for example, that do not exist outside the cell.
The mix of small molecules found here is incredibly complex, as the variety of enzymes involved in cellular metabolism is immense.
These enzymes are involved in the biochemical processes that maintain cells and activate or deactivate toxins.
Most of the cytosol is made up of water, which makes up about 70% of the total volume of a typical cell.
The pH of the intracellular fluid is 7.4. The cell membrane separates the cytosol from the extracellular fluid, but this can pass through it when necessary through specialized channels.
Features
Many cellular processes, mainly metabolic in nature, occur here. These processes include protein synthesis known as genetic translation, the first stage of cellular respiration (glycolosis), and cell division (mitosis and meiosis).
Intracellular fluid allows intracellular transport of molecules through the cell and between cell organelles. Metabolites can be transported throughout the intracellular fluid from the area of their production to the site where they are needed.
Additionally, it plays a major role in maintaining the action potential of the cell. Since the protein concentration is high within the intracellular fluid compared to the extracellular fluid, the differences in ion concentrations both inside and outside the cell become important to regulate osmosis.
This allows to maintain the water balance within the cell to protect it from exploding.
Osmosis and intracellular fluid
Osmosis is the process in which water moves in and out of the cell. Osmotic pressure is the force that moves fluid from one compartment to the other. The osmotic pressure level remains nearly the same between the IFC and EFC compartments.
Osmotic pressure can be defined as the attraction of water to solutes / electrolytes. If there is a decrease in water in the cell, electrolytes move inside the cell to make the water go back in.
Similarly, the opposite happens: when you increase the water in a cell, the electrolytes move so that the water comes out.
For example, eating something with too much sodium makes you very thirsty. What happens is that sodium builds up in the EFC, causing the water to flow out of the cells and dilute it. The cell sends a signal to the brain that the cell is dehydrating so that the person consumes more water.
And again, the opposite also happens. If you have too much water in your body, the cell also sends a signal to the brain. This causes the brain to make the kidneys produce urine to get rid of excess water.
References
- Intracellular fluid: definition of composition. Recovered from study.com
- Extracellular fluid. Recovered from britannica.com
- Intracellular fluid. Recovered from biologydictionary.com
- Cytosol. Recovered from protenatlas.org
- Body fluids. Recovered from courses.lumenlearning.com
- Body fluids and fluid compartments. Recovered from opentextbc.ca
- Cytosol. Recovered from biology-online.org