Download 34-1 PowerPoint Notes

Biologist ___________________________
Date ______________
34-1 PowerPoint – The Endocrine System
Hormones and Glands
The endocrine system is like a radio, “________________” chemical messages.
These chemicals, called ____________, are released in one part of the body, travel through the
blood, and affect cells in other parts of the body.
Hormones can affect almost every _______________ in the body.
Hormones
Hormones act by binding to specific chemical _______________ on cell membranes or within
cells.
Cells that have receptors for a particular hormone are called _______________ cells.
If a cell does not have receptors for a particular hormone, the hormone has ____ effect on it.
Hormones
Many endocrine functions depend on the effects of ______ opposing hormones, such those
shown, to help maintain _______________.
Glands
A gland is an _______________ that produces and releases a substance, or secretion.
_______________ glands release their secretions through tube-like structures (called ducts) out
of the body or directly into the digestive system. _______________ glands include those that release
sweat, tears, and digestive enzymes.
Glands
Endocrine glands usually release their secretions (_______________) directly into the blood,
which transports the secretions throughout the body.
Other body structures, such as bones, fat tissue, the _______________, and the small intestine,
also produce and release hormones.
Prostaglandins
Nearly all cells have been shown to produce small amounts of _______________ substances
called prostaglandins.
Prostaglandins are modified fatty acids that are produced by a wide range of cells. They
generally affect only nearby cells and tissues, and thus are sometimes known as “_______________
hormones.”
Hormone Action
Hormones fall into two general groups—_______________ and _______________ hormones. Each
type of hormone acts on a target cell in a different way.
_______________ hormones are produced from a lipid called cholesterol.
_______________ hormones include proteins, small peptides, and modified amino acids.
Steroid Hormones
Because steroid hormones are _______________, they can easily cross cell membranes.
Steroid hormones act by entering the _______________ of a cell and changing the pattern of
gene expression, making the effects of many steroid hormones especially powerful and long lasting.
1. A steroid hormone enters a cell by passing directly across the cell _______________.
2. Once inside, it binds to a steroid receptor _______________ and forms a hormone-receptor
complex.
3. The hormone-receptor complex enters the _______________ of the cell.
In the nucleus, it binds to regions of __________ that control gene expression.
4. This binding initiates the transcription of specific genes to _______________ RNA (mRNA).
5. The mRNA moves into the cytoplasm and directs _______________ synthesis.
Nonsteroid Hormones
Nonsteroid hormones generally _______________ pass through the cell membrane of their
target cells.
Nonsteroid hormones bind to _______________ in a target cell and cause the release of
secondary messengers that affect cell activities.
1. A nonsteroid hormone binds to receptors on the cell _______________.
2. The binding of the hormone activates _______________ on the inner surface of the cell membrane.
3. These enzymes release secondary messengers to relay the hormone’s _______________ within the
cell.
One common secondary messenger is ____________ (cyclic AMP), which is produced from
ATP.
Other secondary messengers include calcium ________, nucleotides, and fatty acids.
4. These secondary messengers can _______________ or _______________ a wide range of cell activities.
Hormone Action
Steroid and nonsteroid hormones can have _______________ effects on their target cells.
This makes it especially important to understand the ways in which the _______________
system regulates their production and release into the blood.