The Endocrine System Avatar Movie Project Decision Question: Making The Decision

The Endocrine System
Avatar Movie Project
Decision Question: If you were forced to give up one of your endocrine glands, which
one would you give up?
Making The Decision
1. Read pages 490-496 in Textbook B.
2. Read the handouts.
3. Complete the chart, "The Endocrine Glands Data Sheet."
4. Compare/contrast the glands.
5. Based on what you've learned, decide which gland you would give up.
I
Communicating The Decision
Create an avatar movie (http://www.xtranorrnal.com/rnakemovies/) including the
following:
1. Write out the script FLRST, BEFORE going to the website.
2. Share what gland you decided you would give up.
3. Share WHERE this gland is in the human body.
4. Share WHAT (its function) this gland does.
5. Give the reasons WHY you chose this gland.
6. Be sure to communicate your understanding of the consequences of losing the gland
and how its loss will impact your lifestyle.
7. Create an account at xtranormal (http://www.xtranormal.corn/rnakemovies/) and
create your avatar movie.
8. After you have finished the avatar movie, email me
([email protected]) either a) your user name and password to xtranonnal
or b) if you have uploaded your movie to your facebook page email the link to your
avatar movie.
9. Turn in your chart, "The Endocrine Glands Data Sheet" with the names of the students
in your group at the top of the page.
The Endocrine System - An Overview
The endocrine system is a system of chemical control that works
somewhat like a thermostat. Many machines, such as
automobiles and furnaces, have thermostats to regulate
temperature. When the machine becomes too hot, a signal from
the thermostat activates a f a n or other cooling system. Once the
temperature has returned to normal, the lowered temperature
signals the thermostat to turn off the cooling system.
In the human body the endocrine system, in response to signals
from the nervous system, produces chemicals that act to turn on,
speed up, slow down, or turn off the activities of various tissues
and organs. This regulatory action helps the body maintain
homeostasis, a constant, normal internal environment.
The endocrine system is made u p of endocrine glands. An
endocrine gland is a gland without a duct. These glands secrete
chemicals called hormones directly into the bloodstream. A
hormone is the chemical secreted by an endocrine gland that
brings about an effect in a specific tissue or organ. Most
hormones are proteins or lipids called steroids. The specific tissue
affected by a hormone is called a target tissue. The bloodstream
enables all tissues of the body to come in contact with all
hormones, but only specific target tissues react to a specific
hormone. Hormones work in very small amounts.
Hormones are carried to their target tissues by proteins in the
blood. Target tissues "recognize" their hormones chemically.
Hormone molecules fit into sites in +heir target tissues L l e way a
specific key fits into only one lock. Hormones may bring about
permanent changes in target tissues. Reproductive hormones
stimulate the development of secondary sex characteristics in
adolescence.
The Endocrine Glands
The Thvroid Gland
The thyroid gland is in the throat. It secretes thyrodn w h c h
regulates the general rate of chemical activities of cells. I t also
secretes calcitonin, a hormone that takes part in regulabon of the
body's use of calcium.
During a chld's development into adulthood, thyroid hormones
stimulate an increase in growth rate. Release of thyroid hormones
also stimulates mental activity.
If the thyroid is not worhng properly, a person's physical and
mental activity will decrease. Almost every organ system in the
body is affected. The s h n becomes dry and puffy. Hair thms and
becomes brittle. Slow speech, slow reflexes, poor memory,
constipation, and fatigue can result.
If a person doesn't have a thyroid gland, the thyroid hormones ca
be replaced by drugs. He or she ulll have to go to the doctor two
to three times a year for check-ups, and they will .have to have
more iodine in their diet.
The Parathyroid Glands
The parathyroid glands are embedded in the thyroid gland. Their
hormone also functions in the control of calcium and phosphate in
the body. These minerals are necessary for a number of important
body processes, including bone growth and muscle and nerve
funcbon.
Improperly workmg parathyroid glands can lead to extremely low
levels of calcium in the blood. Severe calcium deficiency can
result in tetany, a dangerous condition characterized b y chronic
muscle spasms. The -person may have a feeling of impending
disaster and increased anxiety.
If a person doesn't have parathyroid glands, they can take calcium
supplements or increase calcium in their diet. They will have to
control their anxiety level. They ulll have to visit the doctor two to
three times per year and watch for signs of Eudney stones.
The Adrenal Cortex
There are actually two different endocrine glands in the adrenals,
the adrenal cortex and the adrenal medulla.
The adrenal cortex is the outer part of the adrenal gland which is
located on top of each kidney. It secretes several hormones, one of
which is cortisone. These hormones influence the use and
balance of salts and carbohydrates within the body.
The adrenal cortex is essential for life. Surgical removal
(adrenalectomy) or functional failure due to disease or injury of the
adrenal cortex results in death within a week or two. Death can
be prevented by replacement therapy such as the administrabon
of cortical steroids. Life also may be prolonged by administering
sodium chloride.
Adrenal Medulla
The adrenal medulla is in the central portion of each adrenal
gland. It secretes adrenaline and a related substance,
noradrenahne. These play a part in regulating blood circulation
and the use of carbohydrates in the body. Many biologists believe
that the adrenal medulla helps the body handle emergency
situations.
The adrenal medulla is not essential for life. Evidence that it is
not indispensible is seen in patients suffering from Addison's
disease and in adrenalectomized animals in w h c h life is
maintained by hormones of the adrenal cortex.
If a person doesn't have an adrenal gland and takes hrgh doses of
hydrocortisone or other steroids, they must be aware of the side
effects of steroid therapy: acne, headaches, fatigue, dizziness,
facial swekng, and nausea.
The Islets of Lan~erhans
The islets of Langerhans 'which are located in the pancreas secrete
two hormones. One hormone is insulu? and the other is
glucagon. These hormones have important roles in controlling the
way glucose and some other organic compounds are used in the
body. The familiar disease diabetes melhtus may be a result of
abnormal hnctioning of the islets of Langerhans.
If a person doesn't have the islets of Langerhans, they will have to
take insulin either by shots or by pill. They will have to watch
what they eat and wd1 have to test their blood everyday for glucose
level.
The Pituitary Gland
The pituitary gland is often called the master gland because it
affects so many other body funcbons. It works in close
association w i t h cells of the brain and is under the brain's control.
It secretes a number of hormones. Some of the pituitary
hormones have effects on other endocrine glands. For instance,
the pituitary secretes a hormone (called the thyroid-stimulating
hormone) that controls the secretion of thyroxin by the thyroid
gland. Other pituitary hormones control the rate of bone growth,
the secretion of milk by the mammary glands, the development of
the ovaries and testes, the activity of the adrenal cortex, the
removal of water from the nephrons of the kidney, and the
contraction of the muscles of the uterus.
Sometimes the pituitary gland does not produce the right amount
of growth hormone. When this happens, a midget or giant results.
In midgets, too little growth hormone is produced. Bone growth
stops before normal height is reached. This condition has been
treated by administering growth hormone during childhood. In
giants, too much gram hormone during the developing years
causes an abnormal increase in the length of bones, and a person
grows very large.
If a person doesn't have the pituitary gland, they must replace
various hormones through drugs. They must also see their docto
two to three times a year.
The Reproductive Glands
The testes are the male reproductive glands. In addition to
producing sperm, they secrete testosterone. After fetal life,
testosterone is first secreted in appreciable amounts at the time of
puberty. It influences the events involved in the maturing of the
male. The development of the male reproductive organs is
regulated by the male sex hormones. Usually during the early
teens the male's voice becomes lower in pitch, and hair grows on
his face. These events are controlled by the male sex hormones
secreted by the testes. The production of sperm by the testes has
begun when these events occur. If a man doesn't have testes, he
must receive the hormone, testosterone, usually through pills.
The ovaries of the female which are the female reproductive glands
secrete several hormones that influence the maturing of the
female. These hormones are also necessary for the prenatal
development of the human infant. If a woman doesn't receive the
hormones estrogen and progesterone produced by the ovaries, she
may begin developing characteristics traditionally considered
"masculine" - facial hair, voice that is lower in pitch, etc. She may
also have problems in the monthly reproductive cycle. A woman
without her ovaries would have.to replace these hormones by
taking medication.