Download Endocrine System

Indiana Standard: 8
The Endocrine System
The Endocrine System
Unlike the nervous system, the
endocrine system does not have
its own connected network of
tissues.
Instead, it sends chemical
messages throughout the body in
the blood stream from glands to
target cells.
The Endocrine System
Hormones
The chemicals made by the
endocrine system are called
hormones. Hormones are made in
organs called glands found in
many different areas of the body.
Glands release hormones into the
bloodstream.
The Endocrine System
Hormones
As hormones move
through the body in the
bloodstream, they come into
contact with many different
cells however they only bind
with cells that have
matching receptor cells,
called target cells.
The Endocrine System
Hormones
When the hormones
come into contact with
target cells they bind to
the matching receptor
and signal the cell to
make certain proteins.
The Endocrine System
Hormones
All hormones belong
to one of two
categories:
Steroid or non-steroid
hormones.
The Endocrine System
Hormones
Steroid
Steroid hormones are made
of cholesterol, a type of lipid.
Steroid hormones enter the
cell by diffusing through the
cell membrane. They are able
to enter this way since they
are made of cholesterol.
The Endocrine System
Hormones
Steroid
Remember from biology: cell
membranes are made of lipid
bi-layers, this is why a steroid
hormone can easily pass
through the cell membrane.
The Endocrine System
Hormones
Steroid
Once inside the cell, the steroid
hormone attaches to a receptor
protein inside the cell which
transports the steroid hormone
into the nucleus. After it is inside,
it binds to the cell’s DNA causing
the cell to produce proteins coded
by that portion of the DNA.
The Endocrine System
Hormones
Steroid
The Endocrine System
Hormones
Nonsteroid Hormones
Nonsteroid hormones are
made of amino acids that
cannot pass through a cell
membrane. Instead, they bind
to protein receptors located
on the cell membrane.
The Endocrine System
Hormones
Nonsteroid Hormones
Once bound to the receptor,
the receptor changes chemically
sending a message into the cell.
This chemical message activates
DNA within the nucleus causing
the production of proteins coded
by that portion of DNA.
The Endocrine System
Hormones
Nonsteroid Hormones
The Endocrine System
Glands
The endocrine system has
many glands. Each gland makes
hormones that have target cells
in various places throughout the
body. These are some of the
major glands of the endocrine
system:
The Endocrine System
Glands
Pineal Gland- 1
Structure: Small area in the
middle of the brain.
Hormones:
• Melatonin that regulates
sleep patterns
The Endocrine System
Glands
Pituitary Gland - 2
Structure: Small pea-like structure
in the middle of the brain.
The Endocrine System
Glands
Pituitary Gland - 2
Hormones:
• Growth Hormone (GH)
stimulates cell division, protein
synthesis and bone growth in
multiple tissues.
• Antidiuretic hormone (ADH)
causes the blood to absorb
water from the kidneys.
The Endocrine System
Glands
Thyroid - 3
Structure: Wraps around the
windpipe on three sides.
The Endocrine System
Glands
Thyroid - 3
Hormones:
• Thyroxin (T4) and
Triiodothyronine (T3) increase
metabolism, digestion and a
person’s energy levels.
• Calcitonin causes the body to
remove calcium from the blood
and increase bone formation.
The Endocrine System
Glands
Thymus - 4
Structure: Located in the chest.
Hormones:
• Thymosin causes white blood
cells to reproduce and mature.
The Endocrine System
Glands
Adrenal Glands - 5
Structure: Located above the
kidneys.
Hormones:
• Epinephrine causes the heart to
increase its strength and
number of contractions,
circulating blood more quickly.
The Endocrine System
Glands
Pancreas - 6
Structure: Located between the
stomach and intestines.
The Endocrine System
Glands
Pancreas - 6
Hormones:
• Insulin removes sugar from the
blood stream and increases
sugar metabolism.
• Glucagon increases sugar
production and adds sugar to
the bloodstream.
The Endocrine System
Glands
Ovaries - 7
Structure: Located in female pelvic
area.
The Endocrine System
Glands
Ovaries - 7
Hormones:
• Estrogen causes sexual
maturation, including egg
production, influences female
characteristics such as fat
distribution & widening of hips.
• Progesterone causes
menstruation.
The Endocrine System
Glands
Testes - 8
Structure: Located in male pelvic
area.
Hormones:
• Testosterone causes sexual
maturation including sperm
production and male
characteristic such as facial hair
and a deep voice.
Holt McDougal Biology
By Stephen Nowicki