In patient dialysis, what is the “membrane” and what is the “beaker”?

my teacher gave us a hint but i still don’t get it. plz someone help.

Hint: patient blood is running through a tube made of semi-permeable material. The tube is circulated through a machine containing a dialysate solution of specific components very similar to those in blood acting as a filter

Dialysis relies on the diffusion of solutes and ultrafiltration of fluid across semipermeable membranes. Blood is pumped on one side of a semipermeable (a solid that lets some things through, in this case what is wanted from the blood) membrane and a dialysate (special dialysis fluid) flows by the opposite side. A semipermeable membrane is a critical component of the dialysis equipment.