1. Lab: Simulating osmosis using dialysis tubing

2. What is dialysis?
Dialysis is the artificial process of eliminating waste (diffusion) and unwanted water (osmosis) from the blood.
Our kidneys do this naturally.
Some people, however, may have failed or damaged kidneys which cannot carry out the function properly - they may need dialysis..
Dialysis tubing is used as an artificial replacement for damaged kidneys
Dialysis is also used to rapidly remove toxins or drugs from the blood

3. WARNING: GRAPHIC IMAGE! What do the kidneys do?
When we are healthy our kidneys regulate our body levels of water and minerals, and remove waste.
Approximately 1,500 liters of blood are filtered by a healthy person's kidneys each day. We could not live if waste products were not removed from our kidneys.
Inside the kidney there are MANY MANY small tubes? Why does this help increase the rate of diffusion?

4. What is dialysis?
People whose kidneys either do not work properly or not at all experience a buildup of waste in their blood.
Without dialysis the amount of waste products in the blood would increase and eventually reach levels that would cause coma and death. 
WARNING: NEEDLES AND BLOOD!

5. There are 2 types of dialysis
1. Hemodialysis:
The blood circulates outside the body of the patient - it goes through a machine that has special filters. 
The filtered blood then returns to the patient
The patient is, in effect, connected to a kind of artificial kidney. 

6. There are 2 types of dialysis
2. Peritoneal Dialysis:
A solution rich in minerals and glucose (hyptertonic) is run through a tube into the peritoneal cavity
peritoneal cavity - the abdominal body cavity around the intestine, where the peritoneal membrane acts as a semi- permeable membrane. 
WARNING: GRAPHIC IMAGE!

7. What is dialysis tubing?
Dialysis tubing is a type of semi-permeable membrane tubing used in the separation of molecules from the blood during dialysis

8. The Lab:
You will be using dialysis tubing to conduct an experiment to study osmosis.
In the dialysis tube will be a solution of water or sugar water..
In the beakers will be a solution of water or sugar water…
You will investigate how the water moves through the membrane.
Bag 1
½ full of water
Bag 2
½ full of 20% Sucrose
Bag 3
½ full of 40% Sucrose
Bag 4
½ full of 60% Sucrose
Bag 5

9. Experimental Setup:
Each bag will be placed in a beaker of water or sugar water.
In 10 minute intervals you will measure the change in mass.
What is causing this change in mass?

10. How do you predict each solution will respond? Why?
Bag 1
½ full of water
Bag 2
½ full of 20% Sucrose
Bag 3
½ full of 40% Sucrose
Bag 4
½ full of 60% Sucrose
Bag 5

11. How well does the membrane regulate material movements?
LAB

12. Your objectives for lab:
Test effects of [solute] on osmosis
Determine how size of membrane pores determines what can enter and exit without energy input

14. 2012 data
Percent Mass Change of cells

15. Pore size (Part II)

17. How does tonicity affect animals?
When put in…
Hypertonic Isotonic Hypotonic
shriveled happy lysed

18. How does tonicity affect plants?
Shriveled Wilted Happy

19. Soaking in hypertonic solution
Video

20. Describe the situations these 5 cells are in based on the data