Are you good at chemistry?? Hyper, hypotonic??

SaraO'Hara · Sep 17, 2008

http://209.85.173.104/search?q=cache:hsISBvgMx9AJ:www-isu.indstate.edu/mary/fldnote.htm+%22hypotonic+dehydration%22&hl=en&ct=clnk&cd=1&gl=us may help.

Dehydration of any kind would reduce the fluid volume... hence hemoconcentration? :stone

oregonchinamom · Sep 17, 2008

The cells fill with fluid and swell, but the plasma volume decreases from lack of water. The more cells in the plasma but less water= a higher concentration of the cell to fluid ratio and so it reads as hemoconcentraction.

mcubed45 · Sep 17, 2008

you're confusing the definition of hypotonicity with hypotonic dehydration.

hypotonic dehydration = water loss RESULTING in hypotonicity

in other words, you lose mostly pure water. this means you've got the same amount of "stuff" in the body but less water. how has the concentration in the body changed as a result?

loricatus · Sep 18, 2008

It might help you if you try to visualize it this way:

Think of a glass of water filled with 1/4 marbles.

Let's say that when that marble glass is half full of water it would be considered an isotonic state.

Now, if were to rain and the glass filled with water, you would still have the same amount of marbles in the glass; but, now being filled with water it would be considered to be a hypotonic (diluted in regards to the marbles in its normal state of water in the glass)

If the glass were to sit out in the sun and the water started evaporating into that cloud that gave the rain, the water level would go down in the glass and those marbles would be concentrated into the small amount of water that remains in the glass (hypertonic solution now because same amount of marbles in less water.

If you are catching my drift here, the marbles are representing the particles/substances in the bloodstream (vascular), the glass could be considered the vascular space, water is representing the blood and that cloud is a cell.

The shift of the water through evaporation into the cloud, which depletes the vascular space of blood (water) will result in the vascular being hypertonic; but, the cloud (cell) is now hypotonic.

So, when you here hyper, hypo or iso tonic, it is always referring to the vasculature concentration of marbles (substances) to the water (blood/plasma) and not the cells or extracellular spaces.

Did this help, or did I confuse you more?

icyounurse, BSN, RN · Sep 18, 2008

Hi all. I am a pretty good nursing student, but I am VERY confused with what should be a basic concept. Here goes:
I have read that with a hypertonic state, fluid is pulled from the cell into the vascular space. The cell shrinks. Ok. With hypotonic, water goes from the vascular space into the cell and it swells. Ok. Got it. Well here is where I get CONFUSED!!
WHY with hypotonic dehydration with plasma volume deficits do you get hemoconcentration?? It says 'only water is lost and other substances remain.' I thought in hypotonic situations the cell SWELLS and gains fluid, so HOW is water LOST?? I am not getting the concept on how the shifts go. Can anyone help me???

Because if water is lost then more "substances" like plasma proteins, sodium, ect are left. Throw out the word hypotonic if its confusing and just think dehydrated, your ratio of substances to water is going to change as water disappears, resulting in hemoconcentration. Less water= lass places for blood cells, plasma protiens, ect to go and the blood is "thicker".

Good luck!!

Reno1978, BSN, RN · Sep 18, 2008

I thought in hypotonic situations the cell SWELLS and gains fluid, so HOW is water LOST?? I am not getting the concept on how the shifts go. Can anyone help me???

The shift of water is from the vascular space to intracellular space, so the remaining vascular volume is what gets dehydrated.

BradleyRN · Sep 18, 2008

Hypotonic dehydration means that more sodium has been lost than water from the intravascular space (the vessels). Thus, blood serum levels are hypotonic as related to the cells, causing fluid to shift into the cells.

Hemoconcentration refers to the concentration of RBC's in the plasma. If you had 100 RBC's in 100ml of plasma, that would be 1 RBC per ml. If 50ml of water shifted into the cells, then there would be 100 RBC's in 50ml of plasma, or 2 RBC's per ml. This is hemoconcentration. :)

SweetTeaRN, BSN, RN · Sep 18, 2008

These are all great answers. I just want to remind you that ther terms hypertonic or hypotonic does not always refer to the concentration of particles in the cells. The terms can also be used to apply to the solution. (ie, you can have a cell in a hypotonic solution vs. the cell is hypotonic). Try not to concentrate so much on memorizing what the terms mean. It is more helpful to think about where the majority of the fluid is and where the majority of the particles are.

WHY with hypotonic dehydration with plasma volume deficits do you get hemoconcentration?? It says 'only water is lost and other substances remain.'

Think...the pt. is dehydrated (or hypovolemic...). PLASMA VOLUME DEFICIT...there is not enough plasma outside of the cells, in the interstitial space (plasma=fluid). There are the same number of RBC (hemoconcentration) no matter where the fluid is, so the pt. is therefore hemoconcentrated.

Epona · Sep 18, 2008

THANK YOU VERY MUCH! Those were all very good answers. I was getting confused on the RELATION to what was inside the cell vs. the outside of the cell. My husband (of all people, yet he is a builder and does blueprints so he is good at fine details), was able to expalin it to me by drawing a pic. I see why. It's a hypotonic cell (lots of water), because the water was pulled from the vascular space into the cell. So the cell swells. Because the water was pulled from the vascular space, that space has less water and more solute... hence the blood is hemoconcentrated. By George, I think I got it!! :yeah:

Thanks to everyone!! :clown: