Concept preview

What you will be able to do

1. 01Locate the major endocrine glands and state a key hormone for each.
2. 02Explain why the pituitary is called the "master gland".
3. 03Describe type 1 and type 2 diabetes and how they differ.
4. 04Explain hypothyroidism and hyperthyroidism as examples of failed feedback control.

The endocrine system is not one organ but a scattered team of glands, each tucked into a different part of the body and each releasing its own hormones into the blood. Because they share no single location, it helps to picture them as a map, running from the brain down to the reproductive organs. In this topic you will meet the main players — the hypothalamus and pituitary, the thyroid and parathyroids, the adrenal glands, the pancreas, and the gonads — learn a key hormone for each, and see why the pituitary earns its nickname of the "master gland". Finally you will see what happens when this careful control breaks down, using diabetes and thyroid disease as examples of feedback gone wrong.