The hypotonic, isotonic and hypertonic solutions they are ways of naming homogeneous mixtures formed by a solute that can be classified as crystalloids and colloids (Thomas Graham, 1861). They have the ability to dissolve in a solvent such as water (H 2 O), considered the universal solvent.
In the group of crystalloids Graham selected those that have a good ability to dissociate in water and form ions, so they can be dialyzed and diffused through the semipermeable membranes of the cell. Examples of these are NaCl and / or sugar in different concentrations (osmolarities) or in different proportions.
Crystalloids are the solutes that form isotonic, hypotonic and hypertonic solutions. Among the colloids placed those substances that do not dialyze and do not diffuse through the cytoplasmic membranes, or do so very slowly.
When the solvent in which they are dissolved is evaporated, a gummy residue remains. In contrast, the crystalloids leave a crystalline solid residue.
Index
- 1 Hypotonic solutions
- 1.1 Plasma membrane
- 1.2 Reduction of osmotic pressure
- 1.3 Mushrooms and vegetables
- 1.4 Example
- 2 Isotonic solutions
- 2.1 Examples
- 3 Hypertonic solutions
- 3.1 Examples
- 4 References
Hypotonic solutions
To study the kind of hypotonic, isotonic and hypertonic solution, it is necessary to have a standard solution that serves as a comparison. For this, it is compared with the concentration of solutes inside the cell.
In a hypotonic solution, the concentration of all the solutes outside the cell - that is, in the extra cellular fluid (LEC) - is lower than the solutes inside the cell, called intracellular fluid (SCI).
In this case, the water that forms the LEC is much higher, so it enters the cell and causes it to increase its volume. Sometimes too much water arrives inside the cell and, as there is no wall, the cell membranes can rupture, causing the cell to burst. This is known as cytolysis; in red blood cells it is called hemolysis.
Plasma membrane
It should be remembered that the cells are simply a solution surrounded by a semipermeable bag: the plasma membrane. The plasma membrane is able to prevent solutes from diffusing through the cell membrane, while allowing water to diffuse by osmosis through the membrane into the cytoplasm.
The membrane is composed of special proteins called membrane transport proteins, which help transport specific solutes through the membrane.
Other proteins called aquaporins maintain open channels through which only water can pass. Cells must regulate their solute and water content, since they allow them to perform many of their chemical and biological functions.
Reduction of osmotic pressure
In an intravenous (IV) fluid therapy, it must be taken into account that hypotonic solutions reduce the osmotic pressure in the plasma, causing the fluids that must be administered to invade the cell.
If the solution has a tonicity lower than 150 mOsm / L they can cause hemolysis; that is, destruction of red blood cells or red blood cells - which is accompanied by hemoglobin release - and in brain cells can cause edema and herniation.
In people who play sports, these solutions should only be consumed before starting training, as they are useful as moisturizers. Its consumption is recommended during the exercise according to the intensity.
Mushrooms and vegetables
Superior plants and fungi, whose cells have a semipermeable cell wall, control the environment of their cells in such a way that they are always kept in a hypotonic medium.
This means that when water enters the interior of the cells, they are filled with water presenting the phenomenon of turgor. This causes the cells to become more erect and push each other to remain rigid. Between them, solutes are recycled to maintain the proper water level within your cells.
If a fertilizer is added to a garden, the amount of solute will be higher in the LEC of the cell compared to the LIC. This causes the water to drain from the inside of the cells and, therefore, the garden withers and dies.
Example
Water is the quintessential example of a hypotonic solution.
Isotonic solutions
Isotonic solutions are those that have a concentration in solutes or equal osmolarity inside and outside the cell. The osmotic pressure is the same, so there is always a balance between the LEC and the LIC, which are separated by a membrane.
These solutions are very important to hydrate the intravascular compartment in situations of loss of large amounts of fluids and hemorrhages, among other scenarios. It is necessary to administer between 3 and 4 times the volume lost to achieve the replacement of fluids.
Examples of this type of solution are physiological saline - consisting of 0.9% saline - eye drops used to freshen and clean the eyes and the 5% dextrose solution called Ringer lactate.
Isotonic drinks are those that contain a concentration of salts, minerals and sugars similar to those found in the blood, with a concentration of 300 mOsm / L. Its purpose is hydration and replacement of electrolytes.
They are recommended when there is excessive sweating due to intense heat, and during exercise if the duration is more than one hour and it is very intense.
Examples
Gatorade, Iso drink, Iso energy
Hypertonic solutions
In this class of solutions the solute osmolarity in the LEC is greater than in the LIC. The osmotic pressure generated causes the water present inside the cell to pass to the extracellular part.
These solutions are very useful when the cells have water intoxication, when they have been in a hypotonic medium for a long time and they are swollen. Therefore, an administration of hypertonic solution causes a cellular dehydration and would be beneficial for the cell.
However, when the cell is for a long time in a hypertonic medium, it loses water until dehydration in such a way that it shrinks and wrinkles.
Hypertonic drinks are those that have a concentration of sugars and minerals higher than that in the blood: more than 300 mOsm / L. Due to the large amount of carbohydrates, it forces the cell to release water to be able to assimilate them, which causes cellular dehydration.
These drinks are only recommended after a very intense exercise and it is recommended to consume them in a moderate way.
Examples
The most commonly used intravenous hypertonic solutions are:
- Saline or 3% sodium chloride and 7.5%
- Dextrose solutions at 10% and 40%.
- Combinations of saline and dextrose or glucosaline serum.
References
- Alcaraz R, M., (2015), ndnatural, hypotonic, isotonic and hypertonic drinks. Recovered ndnatural.net
- Sánchez G, J, L., (S.f), Biological membranes (pdf), Recovered: iespando.com
- Salinas, E. (s.f). Isotonic, hypertonic and hypotonic drinks - Differences and applications, NutriResponse. Retrieved from nutriresponse.com
- Vasquez I, M., (2015). Hypotonic, Isotonic and Hypertonic Solutions, SlideShare, retrieved from www.slideshare.net
- Biology Dictionry., (S.f). Hipotonyc Solution, retrieved from biologydictionary.net
- Merino de la Hoz, F. (s.f). Topics 1,2,3.Intravenous Therapy, Clinical Nursing I (PDF), Recovered from unican.es
- Chaverri-Fernández J, Díaz-Madriz J, Cordero-Garcia E., (2012). Generalities about fluid therapy and electrolyte disorders, focus on hospital pharmacy: First Part. Magazine Pharmaceutical Care LA PHARMACOTERAPIA Academic Publication of the Faculty of Pharmacy, volume 1 (2), pp28-39. magazines.ucr.ac.cr