The Endocrine System

-Karthik Gurumurthy

The endocrine system acts as the brain’s assistant. It sends substances with chemical messages from the brain, telling the body what to do to maintain homeostasis, how to grow and develop, when to reproduce, and how to deal with stress.

These chemical substances are called hormones. There are many kinds, and each carries specific instructions. One hormone tells an animal it needs to eat more. Another tells it when to sleep.

The word “hormone” comes from the Greek word hormon, which means “to excite”. Hormones can stimulate, or excite, an animal’s body to do amazing things. They instruct a caterpillar how and when to change its body into a moth or butterfly, and they tell a chameleon to change its body color to match its background. In humans, they let your body know when to grow and how to develop.

Hormones are produced in special organs called glands, found throughout the body. Each gland stores its hormones until the nervous system instructs it to send them as a message. For example, when an animal becomes scared or excited, the brain tells the adrenal gland to send the hormone adrenaline through the body. Adrenaline is called the “fight or flight” hormone. It prepares an animal’s body to run away from danger, fight for survival, or handle other stressful situations. When a cheetah chases an antelope, both animals use adrenaline. Adrenaline helps the antelope flee from danger and the cheetah to catch the food it needs to survive. When you are nervous or excited- on a roller-coaster ride for example- adrenaline makes your heart beat faster.

Two hormones,insulin and glucagon, help to maintain the homeostasis of a body’s blood sugar. If there is too much sugar in the blood-after eating ice cream, for instance-insulin tells the body to store the extra sugar for later. If there is not enough sugar in the blood, glucagon tells the body to take stored sugar and return it to the blood.