Define the following key terms
- Endocrine system
- Hormones
- Hypothalamus
- Pituitary gland
- Anterior pituitary gland
- Posterior pituitary gland
- Thyroid gland
- Parathyroid gland
- Adrenal gland
- Adrenal cortex
- Adrenal medulla
- Pancreas
- Gonads
- Testes
- Ovaries
- Pineal gland