Need help with a question on practice test for A&P

Right, look at the concentration gradient of the cell vs. the distilled water. Will it draw fluid into the cell, out of the cell, or stay the same?

Hi!

I think that the correct answer would be hypotonic. If the blood cell were placed in distilled water, the cell would swell, because the concentration of water on the outside is more that in the inside of the cell. To balance things out, the excess water on the outside would move into the cell,thus causing the cell to swell.

If a red bloodcell is placed in a test tube of distilled water, the red bloodcell would be_______ to the distilled water?

a. hypotonic

b. isotonic

c. hypertonic

I know there is somebody very smart on this board who can answer this correctly.....it's giving me a headache

Your help is needed and very much appreciated.

Thank you

Hi!

I think that the correct answer would be hypotonic. If the blood cell were placed in distilled water, the cell would swell, because the concentration of water on the outside is more that in the inside of the cell. To balance things out, the excess water on the outside would move into the cell,thus causing the cell to swell.

Actually, the original question is what is the RBC to the solution (which is not normally how this question is worded). The RBC swells because its osmotic pressure is higher than that of the distilled water; therefore, the RBC is hypertonic to the solution. The solution is hypotonic to the RBC. A saline solution would be isotonic to the RBC. However, you are correct, the water moves into the cell because of the basic rule of diffusion - there's a higher concentration of solute (salt) inside the cell than in the solution, and since the basic rule of semipermeable membranes is in the case of osmosis "water follows salt." The RBC would swell and possibly burst. I've never seen this question worded this way...usually it's what is the solution to the RBC, which is what I think is causing the confusion....JMHO

This exact question is in a quiz on the online supplements to my text (Tortora / Derrickson) and the answer is hypertonic ... I am very glad for JKCMom's explanation because I took the quiz last night before actually reading the entire chapter (lol for fun -- I had read about 8 pages in and was quitting for the night and wanted to see if I'd learned anything) .... I guessed correctly but didn't know the explanation or definition, etc. LOL Guess I'm about to find out more today when I continue my chapter today!

This exact question is in a quiz on the online supplements to my text (Tortora / Derrickson) and the answer is hypertonic ... I am very glad for JKCMom's explanation because I took the quiz last night before actually reading the entire chapter (lol for fun -- I had read about 8 pages in and was quitting for the night and wanted to see if I'd learned anything) .... I guessed correctly but didn't know the explanation or definition, etc. LOL Guess I'm about to find out more today when I continue my chapter today!

Let me know if you have any more questions - for some reason this stuff and chemistry really clicked with me...strange....

I am now reading about Endocytosis .. fun stuff! I hope it clicks for me too.

LOL oh yeah, that IS strange!! LOL j/k!

I am now reading about Endocytosis .. fun stuff! I hope it clicks for me too.

It all clicked for me when I took the class, but then I guess it clucked & flew away.

:rotfl:

It all clicked for me when I took the class, but then I guess it clucked & flew away.

:rotfl:

OMG! LOL :chuckle

If a red bloodcell is placed in a test tube of distilled water, the red bloodcell would be_______ to the distilled water?

a. hypotonic

b. isotonic

c. hypertonic

I know there is somebody very smart on this board who can answer this correctly.....it's giving me a headache

Your help is needed and very much appreciated.

Thank you

:thankya: Thank you all for your help, I concluded that the cell is hypertonic to the water, and because of all your wonderful explanations I now understand why.....we don't have an answer key to this practice test which makes things hard, you never know if you get the answers right or not.

I sure hope that I have enough brainmatter to become a nurse :uhoh21:

:thankya: Thank you all for your help, I concluded that the cell is hypertonic to the water, and because of all your wonderful explanations I now understand why.....we don't have an answer key to this practice test which makes things hard, you never know if you get the answers right or not.

I sure hope that I have enough brainmatter to become a nurse :uhoh21:

You do have enough brain matter! Sometimes it doesn't/won't seem like you do (I know, I question myself constantly!) but you'll get through! Just remember with osmotic pressure, is the concentration gradient.

Here are some examples:

1)0.28 m glucose- isoosmatic and isotonic ( to RBC ) - normal

2)0.15 m NaCl- isoosmatic and isotonic(to RBC) - normal

3)0.30 m NaCl- hypertonic-(to RBC) RBC shrink (crenate). H20 leaves.

4)0.33 m glycerin- isoosmatic but not isotonic- RCB swells and bursts. (Crosses membrane slow)

5)0.30 m urea- isoosmatic but not isotonic-RCB swell and burst faster than we can see. ( Crosses membrane fast)

What would happen if a diabetic's glucose increased well above the normal concentration? Well, the blood cells would have a high concentration of glucose, making then hypertonic to the outside of the cell. Water would enter the cell trying to dilute the high glucose, at the same time causing the cell to burst. The patient would become sick and could even go into a diabetic coma.

It helps to understand osmosis.

Osmosis happens naturally in our body. When we eat a lot of salt, some times we can see it by swollen fingers, but this only last a short time because our body balances it out to reach an isoosmatic state. Some people whose body does not use diffusion by osmosis properly can have what is called Edema, where their tissue swells all over and they have to take Rx pills to control it (Hydrochlorothiazide). or HCTZ