Ive an account of the physiological effects of recreational drugs on the human body

This is a Human Biology assignment for a H.E.F.C qualification which i am studying at college. It should be 2000 words and no longer than 2400 words. It should have a seperate reference and bibliography page as well as any appropriate diagrams. It obviously needs a introduction and conclusion as well as title page.
The assignment nedds to contain information on three drugs. these drugs cannot be alchohol, tobacco or caffine.
It must be the physiological effects of each drug that is explained, stating what effect that drug has on the particular part of the body and maybes how that part of the body functioned before the drugs. I have wrote the title of the assignment in the Paper topicsection.
The mark of this paper is out of 30. 8 marks for each drug and the remaining 6 marks for grammar, punctuation etc.