1. THE
ENDOCRINE
SYSTEM
Chemical Messengers
Inside the Human Body

2. What is the Endocrine System?
 The Endocrine System uses chemical
messages to control and coordinate the
body.
 These chemicals are called Hormones.
 A hormone is a specific type of chemical
messenger molecule synthesized and
secreted by a group of specialized cells
called an endocrine gland.

3. Is there more than one type of
hormone?
Yes!
 Hormones are categorized into three
classes, based upon their structure:
 Steroids – lipids derived from cholesterol
Example: Testosterone
 Peptides – short chains of amino acids
Example: Insulin
 Amines – derived from a specific amino acid
called Tyrosine.
Example: Epinephrine

4. What are Endocrine Glands?
 Endocrine glands are ductless, which
means that their secretions (hormones
a.k.a. chemical messengers) are released
directly into the bloodstream.
 These chemical messengers then travel
through the blood stream to target
organs. The hormones then regulate or
cause a specific function to take place in
the target organ(s).

5. What are the different glands and organs
that make up the Endocrine System?

6. The Major Glands & Functions:
 The Hypothalamus & Pituitary Glands: The pituitary gland is under the
control of the hypothalamus. Together, they control many other
endocrine functions. They secrete a number of hormones, especially
those that are important to the female menstural cycle, pregnancy,
birth, and lactation.
 Thyroid Gland: Thyroid hormones regulate metabolism, body
temperature and weight. The thyroid hormones contain iodine, which is
necessary to survive. To encourage iodine consumption, the
government requested that salt manufacturers add iodine to salt.
 The Pancreas: This organ has many functions, but in the Endocrine
System, its primary function is to secrete insulin and glucagon to
regulate blood sugars.
 The Adrenal Glands: These glands sit atop of the kidneys. The parts of this
gland secrete Adrenaline, and other similar hormones min response to
stressors such as fright, anger, caffeine, or low blood sugar.
 The Gonads (Sex Organs): The male testes and female ovaries secrete
hormones to regulate reproductive cycles and functions.
 The Pineal Gland: This gland is located in the center of the brain, and is
stimulated by the nerves from the eyes. This gland is responsible for
producing Melatonin which makes you tired. The Pineal gland helps
keep your body on a regulated time clock.

7. Let’s Summarize:
 The endocrine system is one of the body’s main systems for
communicating, controlling and coordinating the body’s
work. It works with the nervous system, reproductive system,
kidneys, gut, liver, pancreas and fat to help maintain and
control the following:
 body energy levels
 reproduction
 growth and development
 internal balance of body systems (called homeostasis)
 Responses to surroundings, stressors and injury