1. Endocrine System
The endocrine system is a system of glands, each of which secretes hormones into the blood stream to regulate the body.

2. Homeostasis
Homeostasis is maintaining a stable internal environment. It is the job of the endocrine system to make sure that

3. Negative Feedback
Negative Feedback occurs when a change in conditions in the environment triggers responses in your body that counteract that change.

4. Thermoregulation

5. Cellular Communication and Hormones
Chemical messengers called hormones trigger many of the responses that maintain homeostasis.
Hormones are secreted by organs of the endocrine system called endocrine glands.

6. Target Cells
Hormones are secreted into bodily fluids. It may reach all parts of the body, but, only certain cells, called target cells are equipped to respond to that particular hormone. This is because of the presence of a special receptor.
Specificity

7. Regulation of Metabolism
The thyroid gland regulates the metabolism with the hormone thyroxin.
Hyperthyroidism is an overactive thyroid gland.
Hypothyroidism is a under active thyroid.
The thyroid also controls the amount of calcium in the body.

8. Calcitonin and parathyroid hormone

9. Insulin and Glucagon
The Pancreas releases insulin to stimulate uptake of glucose from blood. Lowers Blood Sugar Level.
The pancreas also secretes glucagon which stimulates breakdown of glycogen to glucose in liver. Raises Sugar level.

10. Ovaries and Testes
Ovaries release estrogen which is responsible for secondary sex characteristics and progesterone which controls the thickness of the uterus.
Testes release testosterone which is responsible for secondary sex characteristics in males and causes sperm to mature.