Critical Thinking -

Inside a

Dialysis Machine

Done by:

Tan Jiefeng (21)Nicholas Tay (22)Wang Shiyao (23)Class 1I1

What is Kidney Failure?

• Not able to remove waste and extra water from the blood or keep body chemicals in balance.

• Needs the help of a Dialysis machine.

What is Dialysis?

• Dialysis is the cleansing of blood through a special machine.

• Dialysis machines help to remove the waste products from their blood.

How does a Dialysis Machine work?

• Path which blood takes:

What is inside a Dialyzer?

• Inside a Dialyzer, there is a semi-permeable membrane.

- On one side there is blood.

- On the other side there is a special solution called dialysate.

What is inside a Dialyzer?• Dialysate is a solution that pulls

waste from blood.

What is diffusion?

Diffusion is the movement of substances

from an area of HIGH CONCENTRATION

to an area of LOWER CONCENTRATION.

Semi-permeability

• Smaller substances are able to pass through the semi-permeable membrane

- Because they are small enough.

• Bigger substances cannot pass through the semi-permeable membrane

- Because they are too big.

Question 4a

How do you think the waste

substances in the blood such as urea is removed from

the blood?

Question 4a• They are removed from the blood in the dialyzer. • In the dialyzer, the blood with waste products

will flow past one side of a semi-permeable membrane.

• On the other side of this membrane, there is a special substance called dialysate, which pulls waste from blood. The waste such as urea will pass through the membrane.

Question 4b

Will the red and white blood cells and platelets

which make up the blood be removed?

Why?

Question 4b

• The red and white blood cells and platelets will not be removed.

- This is because they are too big to pass through the semi-permeable membrane in the dialyzer and thus will return to the blood compartment.

Question 4c

Diffusible substances needed by the body such as sugars, amino

acids and certain amounts of salts can go through the membrane. What can be done to make sure that these substances are not

removed by dialysis?

Question 4c

• To make sure that these substances are not removed, the concentration of these substances on the other side of the membrane has to be the same.

- This is because diffusion is substances moving from a higher concentration to a lower concentration,

- If the concentration on both sides of the membrane is the same, then the substances will not move.

Question 4d

Water from the blood can also diffuse through the membrane. Why is it not

removed by dialysis?

Question 4d

Similarly, if the concentration of water on the other side of the membrane is the same as that of blood, then there will be no diffusion, and no movement of water.

Concepts

DiffusionSemi-

permeability

Bibliography

• images.google.com • http://dialysis-patient-care.blogspot.com/ • http://www.wisegeek.com/what-are-amino-acids.htm • http://kidney.niddk.nih.gov/kudiseases/pubs/hemodialysisdose/ • http://www.answers.com/topic/how-does-kidney-dialysis-remove-

waste-products-from-the-body • http://wiki.answers.com/Q/What_is_removed_by_dialysis • http://en.allexperts.com/q/Biology-664/Dialysis.htm • http://en.allexperts.com/q/Molecular-Biology-1353/Dialysis.htm

Thank you!