1. KEY CONCEPT The endocrine system produces hormones that affect growth, development, and homeostasis.

2. Hormones influence a cell’s activities by entering the cell or binding to its membrane.
Glands are organs of the endocrine system.

3. Hormones are chemical signals that influence cell’s activities.
produced by glands
travel through the circulatory system
affects cells with matching receptors
target cell
hormone
bloodstream
receptor
not a target cell

4. There are steroid hormones and nonsteroid hormones.
Steroid hormones enter the cell.
Nonsteroid hormones do not enter the cell.
Steroid hormone
Non-steroid hormone
Steroid hormone diffuses through the cell membrane
Steroid hormone binds to a receptor within the cell.
The hormone and receptor enter the nucleus and bind to DNA
Steroid hormone causes DNA to make proteins.
Nonsteroid hormone binds to receptor on the cell membrane.
Receptor stimulates a second messenger with in the cell.
Second messenger starts a series of chemical reactions in the cytoplasm.
Second messenger reactions activate enzymes.
receptor
receptor
second messenger
nucleus
Chemical reactions
DNA
activated enzymes
proteins

5. Endocrine glands secrete hormones that act throughout the body.
There are many glands located throughout the body.
HYPOTHALAMUS
PITUITARY
THYROID
THYMUS
ADRENAL GLANDS
PANCREAS
FEMALE GONADS :OVARIES
MALE GONADS : TESTES
Hormones travel through the bloodstream to cells with matching receptors.

6. The hypothalamus interacts with the nervous and endocrine systems.
The hypothalamus is a gland found in the brain.
a structure of both the nervous and endocrine systems
produces releasing hormones, sent to pituitary gland
The pituitary gland is found below the hypothalamus in the brain.
controls growth and water levels in blood
produces releasing hormones sent throughout the body

7. Releasing hormones stimulate other glands to produce hormones.
allow glands to communicate with one another
are used in temperature regulation

8. Hormonal imbalances can cause severe illness.
Abnormal hormone levels affect homeostasis.
Hormonal imbalances might be treated with surgery or medicine.
Steroids, a pituitary tumor, or some prescription drugs can make the pituitary overactive and indirectly cause problems.