Use of human body tissue and fluids: Is it ok to use human body tissue or fluids such as cheek cells or tears in science experiments in schools?

Use of human body tissue and fluids: Is it ok to use human body tissue or fluids such as cheek cells or tears in science experiments in schools?
This resource deals with the non-renewable mineral resources.
This online resource is a web page that gives basic information on acids and bases including how to make litmus paper with cabbage water and how to perform a titration with vinegar.