Osmosis can be defined as the diffusion of a solvent (water) across a selectively permeable membrane from an area of less concentration of solutes (such as salt) into an area with a higher concentration of solutes. This is an important scientific concept that has many practical applications in medicine, paramedics, nursing and many areas of general science and physics.
Practical Examples of Osmosis in Medicine
Basically, this concept becomes important when we start to administer hypertonic or hypotonic solutions. We understand that if we were to admister 100% sterile water intraveneously to patients who are dehydrated, the cells within the vasculature (blood vessels) would draw up all that fluid due to the osmotic gradient shift (this basically means that the fluid will want to shift into the cells) and this will cause the local cells to swell and lyse (rupture). This means that the red blood cells themselves will no longer be capable of carrying oxygen and serving their purpose.
Likewise, if you were to administer 50% glucose intravenously, the hypertonic solution (lots of solutes) will cause a lot of fluid to shift towards it. Now, so long as the canula is in a large vein, it will be able to draw fluid from a large area. However, if the canula is inserted in a small vein or accidentally inserted into the intersitial space and not a vein, it will not be able to draw fluid from all over, and consequently draw all the fluid from the surrounding cells. This will cause the cells to shrink (crenate) and again, become unable to sustain life. In these circumstance, patients may develop cellulitis or damaged veins.
Examples of Osmosis in Cells?
This becomes important when looking at the structure of cells in biology.
If a cell has a high concentration of a solute (salt) it will draw fluid into its cell. If allowed to continue to do this, it will eventually swell up and rupture (this is called cell lysis).
If a cell has a low concentration of a solute it will lose fluid as the fluid within its cell is allowed to be drawn out of the cell through osmosis and into the intersitial space. This will cause the cell to shrink (this is called cell crenation).
Examples of Osmosis Applied
The following are examples of osmosis for those of you who need to see an example to clearly understand science (like me)…
Example of osmosis 1.
If you put rice into a bowl of water, the water will move into the rice causing them to swell, while causing the water level to drop.
Osmosis example 2.
If a cell is placed in a container which is full of a hypotonic solution (not many solutes) than the fluid in that container will naturally want to be drawn into the cell and this will cause the cell to swell up and rupture (lyse).
Example of osmosis 3.
If a cell is placed in a container which is full of a hypertonic solution, than the cell will lose fluid as it is diffused outof the cell into the area of greater solute concentration. This will cause the cell to shrink (crenate).
Example of osmosis 4.
In medicine, if a patient drawns in salt water, the hypertonic water in the lungs will cause more fluid to be drawn out of the pulmonary arteries into the alvioli and lungs. This will more often result in pulmonary oedema than a patient who has drawned in fresh water.
Example of osmosis 5.
If you admister normal saline to a patient intraveneously (which has the same osmolarity as blood / the same amount of solutes as blood) it will mean that the fluid remains unchanged, because their is no osmotic gradient (basically all the fluid stays the same). Now, if you were to give mannitol (which is a very hypertonic solution) the fluid within the blood will be drawn out of the cells and into the mannitol solution.
Example of osmosis 6
When the stem of a plant is cut and placed in water (for example a vase), the water will move up through the stem by a process of osmosis, in which the water is flowing to the higher concentration of solvents (found in the plant).
By understanding these examples of osmosis you will be able to better apply the concept of osmosis to practical uses in medicine, paramedicine, nursing, and many fields of general science.