Negative and positive feedback loops


First lets begin with a very good introduction to the term homeostasis:
Homeostasis

Here is a tutorial on negative feedback loops:
Negative feedback loops

Positive and negative feedback







A more profound explanation of diabetes may be seen here:






Here is some relevant information about the endocrine system:
Endocrine system


Similarly here are some presentations on thermoregulation:
Thermoregulation
Action of thyroxine