Download The Endocrine System

The Endocrine System
Puberty is just one of the things controlled by hormones from the endocrine
system.
Ever wondered how your body stays around the same temperature, or why you
fall asleep and wake up automatically?
The endocrine system is in charge of making sure that your body’s many
functions are coordinated. It’s made up of groupings of cells called glands.
There are eight major glands: the pituitary gland, the thyroid gland, the adrenal
glands, the pineal gland, the pancreas, the thymus, the parathyroid, the ovaries
in women, and the testes in men.
The glands make more than 30 types of hormones, each with their own special
job. Hormones are responsible for regulating your metabolism, mood, growth,
and organ function. A part of your brain, called the hypothalamus, is critical to
your endocrine system. It monitors you’re your body and sends information to
your pituitary gland.
The pituitary gland is attached to the hypothalamus, and is like the king of the
endocrine system. It sends out its own chemical messages and rules the actions
of most of the other major endocrine glands. Each gland has a different job.
The thyroid releases hormones that control how fast your body’s cells burn
energy. That’s important, because it affects how other parts of you grow and
develop.
The parathyroid glands keep the calcium level in your blood at a certain level.
If, say, your blood has too much or too little calcium, your nerves and muscles
don’t work right.
The adrenal glands regulate your body’s response to stress. They release the
hormone adrenaline in dangerous or exciting situations. It gives you a quick burst
of speed and strength.
The function of the pineal gland isn’t fully understood yet. All we know is that it
secretes a hormone called melatonin that’s thought to influence our sleep cycle,
metabolism, and sexual development.
The pancreas secretes the hormone insulin, which regulates your blood sugar.
You’ve probably heard of diabetes Type 1, that happens when the pancreas can’t
produce enough insulin to control your blood sugar.
The thymus helps your body fight off infections. It’s a key player in the
production of T-cells, which identify and kill germs in your blood.
Finally, there are the ovaries in women, and the testes in men. These glands
produce hormones that help us reach maturity, fight infections, stay energetic,
and more! They also produce the sex cells for reproduction.
No matter what gland produces them, hormones all work in the same basic
way: On one side we have the cells and glands that produce hormones. And on
the other side we have the cells and tissue that responds to the hormones. When
glands secrete hormones into the bloodstream, the hormones travel to target
cells or target tissue. When the target’s receptors get their chemical message,
they go to work carrying out their function.
Every cell in your body has receptors for particular hormones.
The endocrine system works in cycles. It produces hormones and the hormones
do their job, causing many different things to happen in many different types of
cells. Think about how you suddenly start growing in your teen years. When it’s
time for a growth spurt, the pituitary gland sends out a growth hormone that tells
your cells, “It’s time to grow up! Start dividing!” When your body is finished
growing, your cells will produce chemicals that will stop the growth hormones
from being released. That’s why you stop growing. This is called negative
feedback, and it’s how most hormone production is regulated. When a job’s
done, negative feedback occurs and the hormone production stops until it’s time
for the whole process to start over again.