Endocrinology - It is the study of endocrine system, this endocrine system is composed of glands in different parts of the body as you can see on the picture above. The primary function of endocrine glands is to release hormones, the function of this so called hormones is to control reproduction, metabolism,growth and development in short to maintain homeostasis (normal body function).
So imagine life without hormones? let's just say for example you don't have any insulin hormone,when insulin is absent, glucose in the blood is not taken up by body cells, glucose is a body sugar and having too much of it the blood (diabetes) causes a lot of health problems in the eyes,nerves,kidneys which can lead to blindness,dialysis, or even in much worst case scenario is amputation, ouch!.
Toxicology - Study of harmful toxic effects o substances/chemicals, also called as the science of poisons.Toxicology has many aspects like food toxicology,environmental toxicology and clinical toxicology.But eventhough it looks like politics that has many groups and divisions, it has only one goal.That is to give proper information and understanding of how chemicals can bring adverse effects on living organisms.
Drug Testing - Program created by the law to solve widespread problem of drug abuse and its consequences.When you take in anything inside from the food that you eat, drinks and drugs. The body will break down all of them into smaller particles and they will be digested and eventually go out of the body, but not the drugs, its metabolites can remain in the body for long period of time.