Hypotonic VS Hypertonic

[deleted92121]

Can someone please explain hypotonic and hypertonic to me?

Hyposmotic and Hyperosmotic as well.

I am so so confused..🙁

dxu

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[Pdiddy310]

take this example:

place a cell (300 mOsm) into a solution that is 400 mOsm sucrose.

The solution is hyperosmotic b/c it contains more osmotically active particles than the cell and hypertonic b/c water will flow towards the solution from the cell.

 

[Pdiddy310]

another example:

place a cell (300 mOsm) into a solution that is 200 mOsm sucrose.

The sucrose solution will be hypo-osmotic b/c it contains less osmotically active particles than the cell (200 < 300) and will be hypotonic b/c water will flow from the solution INTO the cell which may cause it to lyse. Recall the law of diffusion. Hope this helps.

 

[deleted92121]

Thank you for the examples..they do help!

dxu

 

[DrWanahbe]

OK, I made this really simple for myself:

The cell will cRenate (shRink) when the solution is hypeRtonic.

The cell will swell when it's hypotonic.

 

[erichaj]

Lets say you have a bottle of distiled water (No salts in it at all).

Now lets say I pour in a huge amount of salt in it. I have increased it tonicity.

Now lets look at it from a cell to cell standpoint.

Cell number one has distiled water, cell number two has very tonic (lots of salt) water in it. If some of that salt from cell number two goes into cell number one, what happens?

The tonicity of cell number one is increased while the tonicity of cell number two is decreased.

Alway remember this type of relationship. Hyper (increased) and Hypo (decreased) only have real meaning when they are relate to something else.
It's this relationship in ions that allows changes to take place in cells.

Hope that helps.

 

[erichaj]

OK, I made this really simple for myself:

The cell will cRenate (shRink) when the solution is hypeRtonic.

The cell will swell when it's hypotonic.

Cells will not always shrink when hypertonic. Tonicity is a concept of how much of a specific ion is in a cell. You know positive and negative charges. It does not always refer to volume in a cell.

Although it is true that if you take the volume (say h20) out of the cell, the tonicity will increase and the size of the cell will shrink.

You have a good way of thinking about it when you think of it as water coming and going. But, what if K+ rushes into a cell, this will change the tonicity without any water leaving. This happens in an action potential in a nerve cell.

 

[DrWanahbe]

Cells will not always shrink when hypertonic. Tonicity is a concept of how much of a specific ion is in a cell. You know positive and negative charges. It does not always refer to volume in a cell.

Although it is true that if you take the volume (say h20) out of the cell, the tonicity will increase and the size of the cell will shrink.

You have a good way of thinking about it when you think of it as water coming and going. But, what if K+ rushes into a cell, this will change the tonicity without any water leaving. This happens in an action potential in a nerve cell.

Ah. I see. I haven't learned this stuff yet! (I'm taking my pre-reqs one class at a time, just started, so right now I'm in Gen Chem) I used the above to remember the very basics about it when I was introduced to the concepts over the summer. Thanks for providing me with more information!

 

[CanadianPre-Med]

HypOtonic --> notice the O resembles a swelled cell; as such, water moves into a cell in a hypotonic solution. The opposite occurs in a hypertonic solution.

 

[deleted92121]

I finally figured it out cuz of all the help here.

thanks a ton!

dxu

 

[Baker]

Could anyone help me understand in what medical condition would a Dr. use a hypertonic IV compared to a hypotonic IV ?

 

[ThirdEye]

Could anyone help me understand in what medical condition would a Dr. use a hypertonic IV compared to a hypotonic IV ?

I don't think they ever use a hypertonic IV. They use eiter normal saline (isotonic), or half normal saline (hypotonic). They sometimes use a isotonic saline that is hyperosmotic if it has dextrose in it.

- If someone is dehydrated, they'll use half normal saline (hypotonic) if their osmolarity is high (hyperosmotic)

- Blood loss will result in an isotonic IV since osmolarity hasn't changed.

I would think it is very rare for someone to be so hypoosmotic that a Dr./nurse would administer a hypertonic IV. It's too risky since it would suck all of the water out of their cells, thus they just give them isotonic saline until there's a balance.

 

[eventualeventer]

*can't sleep, got bored, and wandered over from pre-vet forum*

Actually, there are a couple cases where hypertonic solutions might be used, which I will try to explain using my limited medical knowledge:

- In the case of cerebral edema, hypertonic saline is sometimes used along with osmotic diuretics, etc., to draw water out of the CNS and back into the bloodstream.
- In the setting of hypovolemic or septic shock, hypertonic saline draws water into the vascular space rapidly, supporting circulation and perfusion of vital organs. It is always followed immediately by large amounts of isotonic solutions, so that cellular dehydration does not last long. There is some thought that hypertonic saline may have other effects, such as protecting capillary endothelium and reducing expression of inflammatory mediators, etc.

Where I work, horses who show up extremely dehydrated (usually due to intestinal lesions) and in shock often receive 1-2L of 7% NaCl as part of aggressive resuscitation, usually followed by 30-50L of polyionic isotonic fluids (this is for a 500 kg horse).

 

[Status]

The terms isotonic, hypotonic, and hypertonic refer to whether solutions will cause a change in cell volume. The tonicity of solutions depends on the concentration of impermeant solutes. Some solutes can permeate the cell membrane. Solutions with an osmolarity the same as the cell are called isosmotic, regardless of whether the solute can penetrate the cell membrane.

The terms hyperosmotic and hypoosmotic refer to solutions that have a higher or lower osmolarity, respectively, compared with the normal extracellular fluid, without regard for whether the solute permeates the cell membrane. Highly permeating substances, such as urea, can cause transient shifts in fluid volume between the intracellular and extracellular fluids, but given enough time, the concentrations of these substances eventually become equal in the two compartments and have little effect on intracellular volume under steady-state conditions.

 

[razzmatazz87]

Easy way to remember, oversimplification...

hypOtonic solutions, hypo = low, the cell has more solute, so the cell swells as water travels in, swells to an O shape
hypertonic solutions, hyper = high/a lot of, the cell has less solute than surroundings, so it shrinks

 

[the_fella]

Can someone please explain hypotonic and hypertonic to me?

Hyposmotic and Hyperosmotic as well.

I am so so confused..🙁

dxu

First, it's helpful to know the roots for hypo and hyper. Hypo means low or below. Hyper means above or high (think of a hyperactive person. They have "high" energy.). So, tonicity has to do with the concentration of solute (NaCl is a popular example, but it can be any solute) outside of a cell. If the concentration of solute is greater on the "outside", that means there is less water there, so water flows out of the cell. Since the solute concentration is greater, we call this hypertonic. Now in a hypotonic situation, the solute concentration is lower outside, which means there's less stuff outside (and conversely more water), so water will flow into the cell. It's helpful to think of it with a cell, but it can be applied to any membrane regardless of whether it's a cell membrane. Water (most things, really) moves from an area of high concentration to an area of low concentration.

Have I made it clear as mud?