Match the following items. 1. regulates growth hormones parathyroid gland 2. regulates blood sugar reproductive gland 3. initiates "fight or flight" reaction thyroid gland 4. regulates body's energy adrenal gland 5. regulates calcium levels in the body pituitary gland 6. produces reproductive cells pancreas

The process of hormonal regulation, and the interconnection between the different organs that make part of the endocrine system, is a pretty complex and broad one. Initially, it is important to bear in mind that although we associate certain organs with certain hormones, and the production of certain body reactions, these are not always absolutely straightforward, and sometimes more than one organ will play a part both in the production of a hormone, its regulation, or the generation of a specific reaction. As such, the correct order would be:

1. Parathyroid: Regulates calcium levels. This is one of the most important functions of the parathyroid. It does so in response to blood levels of calcium, making bones begin to release calcium stored in them when necessay.

2. Reproductive gland: Produces reproductive cells. The testes and ovaries are these glands, and they produce the hormones that coordinate our reproductive systems. They also produce the sperm and the oocytes.

3. Thyroid gland: Regulates body´s energy levels. The thyroid is almost like the power plant. Its hormones are responsible for the way that our cells respond to other hormones to regulate energy levels and other functions dependent on metabolism.

4. Adrenal gland: Initiates the "fight or flight" response. The true initiator is the autonomic nervous system, but through neurotransmitters from this system, the adrenal medulla becomes activated to produce epinephrine, the fight or flight hormone.

5. Pituitary gland: Regulates growth hormones. This is done by the anterior pituitary, by the somatotrophic neurons in that center.

6. Pancreas: Regulates blood sugar. The pancreas is the producer of insulin, the hormone responsible for our cells being able to take in glucose and use it for energy production.