Welcome to another Tutor Short provided by the Educational Support Services Department
of Lehigh Carbon Community College in Schnecksville, Pennsylvania which is just outside of Allentown.
These videos review Key Learnings for the science courses provided here at LCCC.
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five days a week.
Let's review the impact Osmosis has on cells.
I've shown here on the left, a representation of how Osmosis has an impact on cells and
blood.
This is reviewed in your Chem 106 course and it is obviously important for pre-nursing
students.
So the semi-permeable membrane is what is important in Osmosis and a semi-permeable
membrane is a membrane that only allows, in this case, Water to pass through that membrane
(sort of like a filter) but other materials, such as Salt and Glucose, cannot pass through
the membrane.
Only Water can move from one side to the other.
So I have here sort of a representation of cells on the left and the cell wall is represented
by this blue line in the middle and on the right is your blood (your bloodstream works
alongside your cells).
And so, I show here on the left a typical level (or a normal level) in cells is 0.9%
Sodium Chloride (that's in a mass per volume basis which is grams per mL) and a normal
Glucose level (Sugar level) is 5% (also on a mass per volume basis).
And so, if you look at the 0.9 and 5 together and say the rest is Water, you end up with
94.1% Water in order to make up the remainder of the solution.
Now on the other side of the cell wall you have your blood and if you have normal levels
of blood (if you're healthy), you should be balanced.
You should have 0.9% Sodium Chloride, 5% Glucose and the remainder 94.1% of Water.
And that's....
So your blood, if it's in balance with your cells, they say your blood is Isotonic or
the solution of your blood is Isotonic.
It means you're at the normal levels of 0.9% Salt and 5% Glucose.
So what happens if say you get sick and something upsets this balance.
So now, let's take the example of low level of Salt or Sugar or both.
We'll use...
I'm going to change both but you could only change one if you want.
Let's say the Salt was a little bit lower at 0.5 and your Glucose was at 2.5.
So they are both low.
Now you have 0.5 and 2.5 with these two materials so that's a total of 3%, So now your Water
is going to be higher so at 97% the remainder is Water.
So what happens here with Osmosis, since only Water can pass across this cell wall (the
membrane), you'll look at your Water concentration on the left inside the cell, it's 94% about.
And on the right here you have 97% Water.
So it's higher.
And so what happens is, the higher concentration of Water is going to try to equalize with
the lower.
Your Water is going to go from right to left - from your blood and into the cells to try
to equalize this to say..
I don't know... 95 and a half or something to get some kind of equal level.
So because Water is now going to pass from your blood into your cell, your cell is going
to gain water up here.
So it's going to gain Water, which means it's going to swell.
So as your cells in your body swell with water (as I show over here on the right), that's
called Hemolysis.
The condition is Hemolysis and that happens when your blood is Hypotonic.
Hypotonic meaning low in the Salt and Sugars so, in this case, this is Hypotonic.
Your blood is Hypotonic - it's low.
Now, let's take the opposite condition.
Now instead of having a lower level of Salts....
Let's say we have a higher level.
So now let's take...
Let's say we have 1% Salt and 9% Sugar.
So that's a total of 10% so now you're at 90% Water.
Now you're higher inside your cell than you are in your blood.
Water, to equalize, is going to cross over from your cells into your blood stream....
to try to get... to equalize between the 94 and the 90.... get somewhere like 92... it's
going to try to do...
And so what's going to happen your Water level in your cell - it's going to go down...
Your going to have less Water in your cell...
Your cells are going to shrink... because of that...
When your cells shrink, the condition you have is called Crenation.
And your blood is at a Hypertonic position or over here...
Hypertonic... pretty lousy handwriting there....
But Hypertonic...
Your blood has more Salt and Sugar in it than normal and you have a Hypertonic situation
in your blood and it's going to cause Crenation of your cells.
And so you have these three situations - Isotonic when everything is normal; then Hypotonic
when your Salt levels are low in your blood; Hypertonic when they are high.
And if you think about... if you where a doctor so you have this situation I show here.
Your blood is high in Salts and you're Hypertonic, You would probably prescribe an intravenous
solution.
The intravenous solution would be the opposite.
It would be Hypotonic.
It would have low levels of Salt and Sugar to then try to balance out these levels in
your blood to get yourself back to your normal levels of 0.9 and 5 and everything back to
balance.
So that's how Osmosis impacts what happens with your cells.
Thank you.