Filtration is the passage through a filter or through a material that prevents passage of certain molecules. The filtration process is usually carried out on blood plasma driven across capillary walls in the excretory organ by blood pressure. The walls of capillaries are permeable to water,to some ions,and to some small molecules,but not to large molecules such as proteins. Blood pressure therefore tends to squeeze water and some solutes out of the capillaries and into the surrounding intercellular spaces.
Dialysis
Hemodialysis Case Study