TEKS 10 A & B, 11A
Endocrine System
Feedback Systems
TAKS Objective 2 – The student will demonstrate an understanding of
living systems and the environment.
TEKS Science Concepts 10 A & B
The student knows that, at all level of nature, living systems are found
within other living systems, each with its own boundary and limits. The
student is expected to:
(A) interpret the functions of systems in organisms including
circulatory, digestive, nervous, endocrine, reproductive,
integumentary, skeletal, respiratory, muscular, excretory, and
immune;
(B) compare the interrelationships of organ systems to each other
and to the body as a whole;
11 A
The student knows that organisms maintain homeostasis. The student is
expected to:
(A) identify and describe the relationships between internal feedback
mechanisms in the maintenance of homeostasis
TAKS Objective 2
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TEKS 7.9 A
For Teacher’s Eyes Only
Teacher Background: There are twelve major organ systems in the human body
(i.e., circulatory, skeletal, respiratory, excretory, integumentary, nervous,
digestive, endocrine, reproductive, immune, lymphatic, and muscular systems). In
this TEKS, we will introduce students to the common structures of each system
and their basic functions. A brief description of these systems follows:
Endocrine System/Feedback Systems - Maintaining homeostasis in the human
body is critical to life. Our body’s ability to monitor and maintain homeostasis is
dependent on a many complex interactions between the various body systems
linked by the circulatory system. The endocrine system plays a vital role in
maintaining this stable environment through the release of hormones that
influence almost every cell, organ, and function of our bodies. When these
interactions do not function properly, a number of problems occur, some of which
can be life threatening.
In this TEKS the student will explore a positive and negative feedback systems
and their role in the maintenance of homeostasis. A negative feedback system is
one that tries to keep the body constant. There are a number of negative
feedback systems in the human body such as those involved in the control of
blood glucose, blood calcium, blood pressure, reproduction, reaction, growth and
metabolism. A very common example is how the body reacts to reverse the
direction of change as the concentration of carbon dioxide in the blood increases.
The diaphragm works in conjunction with the lungs to increase activity to
decrease Carbon Dioxide levels in the body and increase oxygen levels. As water
flows into a flaccid plant cell, the cell begins to swell and push against the cell
wall creating turgor pressure. When the cell wall pressure is great enough, the cell
wall pushes against the turgid cell and no net movement of water will occur
across the cell membrane any longer. Another type of feedback system is a
positive feedback system, which works in a different way.
In a positive feedback system the change will continue to increase in one
direction until something happens in the body to stop it. For example,
contractions of the uterus are triggered by pressure against the cervix during
childbirth. This pressure causes the release of a hormone, oxytocin. The
contractions will continue until the child exits the womb. Testosterone production
is another example of a positive feedback system.
In addition to chemically regulated feedback systems, the body also uses thermal
regulation to achieve homeostasis. In skin cells, there are sweat glands and
receptors for heat and cold. When the body temperature goes up, the
hypothalamus in the brain sends a nerve signal to cause sweat glands to release
water. At the same time, blood vessels in the skin dilate which helps move heat
away from the skin. Sweating cools the body through evaporation. On the other
TAKS Objective 2
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TEKS 7.9 A
hand, in order for the body to keep warm, sweat glands and blood vessels
constrict to conserve body heat. If the body temperature continues to fall, the
skeletal muscles will shiver to produce heat. Finally, as a last resort, the
decomposition of fat will rev up the metabolic rate and produce heat to maintain a
constant body heat.
Student Prior Knowledge
Students should be familiar with the components associated with body systems
TEKS 6.10 (C) identify how structure complements function at different levels of
organization including organs, organ systems, organisms, and populations and the
functions of these systems.
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TEKS 7.9 A
Endocrine System
5 E’s
ENGAGE
Watch clips from the video Sideshow: Alive On The Inside. Student will view
"human oddities" (Siamese twins, pinheads, bearded women) and others with
endocrine disorders. Additionally, students will hear from the performers about
their lives on and off the stage, and more.
If students are still interested, allow them to read the book Freak Show:
Presenting Human Oddities for Amusement and Profit by Robert Bogdan.
EXPLORE
Explore 1
Have student familiarize themselves with the endocrine glands and their functions
by completing the endocrine system worksheet in the Blackline Masters.
Explore 2
Role Play: The Rise and Fall of Glucose
Class Time: 20 minutes
Materials:
Script (see Black-Line Masters)
Laminated cards with drawings of pancreas, muscles, liver, small
intestine, and adipose tissue
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TEKS 7.9 A
Preparation Students participate in a role-playing activity for the
glucose/glycogen feedback system. Create 8” X 12” laminated cards for each
wizard and glucose/glycogen molecule. The laminated card for glucose/glycogen
should have the word, glucose on one side and glycogen on the opposite side.
Attach yarn to form a necklace from which the card is suspended. Create postersize drawings of the pancreas, muscles, liver, small intestine, and adipose tissue.
The play script is available in printable version.
Factoid: You might know someone with an insulin problem whose pancreas is
not working right. These folks have a disease we call diabetes, and if they don’t
get treatment, they could loose a finger, a toe, or other body part that starved to
death from lack of sugar in those particular cells. Diabetes can be a serious
problem for some folks.
EXPLAIN
Complete the Endocrine PowerPoint presentation with your student with
discussion and the completion of the following questions.
1. List 4 types of endocrine glands and give their function. Answers will
vary. Thyroid, Parathyroid, Pituitary, Testes, Ovaries, etc…
2. What is the overall function of the endocrine system? To regulate other
body systems through the use of hormones.
3. With what other systems does the endocrine system interact? All other
system
4. What endocrine gland is often referred to as the master gland? Pituitary
gland
5. What are the two hormones that the thyroid secretes? Thyroxine and
Calcitonin
6. What is the function of thyroxine? Regulate energy usage.
7. What is the function of calcitonin? Regulate calcium and phosphate in the
blood
8. PTH causes the small intestine to absorb more calcium, phosphate and
magnesium.
9. What does PTH cause the bones to release? Calcium
10. What do the kidneys do because of PTH? Reabsorb Ca and Mg
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TEKS 7.9 A
11. What organ regulates glucose in blood? Pancreas
12. When we eat our blood glucose level is high or low? High
13. In between meals our blood glucose level is high or low? Low
14. When our blood glucose is high the pancreas secretes ___________.
Insulin
15. When our blood glucose is low the pancreas secretes ___________.
16. What mechanism allows our body to control the glucose level in our
body? Negative feedback mechanism
ELABORATE
Students should complete the Investigation of Plant Hormones laboratory activity.
Students will better understand human hormones by studying plant hormones that
stimulate and inhibit growth.
EVALUATE
1. Using their text and other resources, the student will correctly match 6 of 8
endocrine glands to their function.
2. Using the text, and class notes, the learner will demonstrate understanding
of how blood glucose is controlled in humans by creating labeled
drawings and providing a 100 word summary of the process. A minimum
score of 70% on the rubric is required.
3. Using available resources, students will develop and conduct independent
investigations to determine the affect of gibberilic acid on plant growth. A
minimum of 70 on the scoring rubric is required.
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TEKS 7.9 A
TAKS Objective 2
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Biology
The Endocrine System
Directions: Match the correct endocrine gland with its function. Label the picture
correctly.
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Biology
The Endocrine Glands and Functions
GLANDS
FUNCTIONS
releases a hormone,
which is involved in
rhythmic activities, such
as daily sleep-wake cycles.
Pineal gland
Pituitary gland
Thyroid gland
Thymus
Adrenal gland
Pancreas
produces a hormone
that regulates metabolism
produces two important
hormones that regulate
the level of glucose in the blood.
produces testosterone, which
is responsible for sperm production
and the development of male secondary
sex characteristics.
Ovary
Testis
often called the master gland; produces
hormones that regulate many
of the other endocrine glands.
releases chemicals into the body
which helps it deal with stress
produces female hormones estrogen and
progesterone required for development of
secondary sex characteristics
and for the development of eggs.
releases a hormone, which
stimulates T-cell development.
Major player in the immune
system
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Biology
THE RISE AND FALL OF GLUCOSE
Act I
Pancreas: I am the pancreas, and I secrete some very important hormones to help
keep your body in perfect balance. One of these hormones you may have heard of
before; it’s called insulin. When glucose, which is a sugar, is high in the blood, I
release insulin to help bring the glucose level back to normal by helping glucose
(sugar) from the food you eat to become stored in the body until you need it.
Stored sugar is called glycogen. Let me show you how this works. Let’s say you
just ate lunch.
Glucose Molecules: Four Glucose Molecules are moving around in the
bloodstream (Five glucose molecules move out from behind the small intestine.
Wow! Are we glad to get out of the digestive system! (Glucose Molecules move
around the middle of the room) Where are we? Where is our home?
Pancreas: (To the audience) Notice that they’re too many Glucose Molecules in
this blood right now. So, I will release some insulin to bring the blood glucose
level back down. (Pancreas releases Insulin Blue Wizard).
Insulin Blue Wizard: Hey, let me show you your new home. Five Glucose
molecules follow Insulin Blue Wizard to the liver, muscles, or adipose (fat) tissue.
The Blue Wizard lightly taps each of the five Glucose Molecules on the shoulder
with a wand and says, “Transform!” (Switch labels). This changes each Glucose
Molecule into a Glycogen Molecule.
Pancreas, Glucose Molecules, and Insulin Blue Wizard perform the Insulin Rap.
Insulin Insulin
Storing sugar is so much fun
Muscles, liver, fat that's right
Get sugar each time you take a bite
Act II
Pancreas: But having only one job is boring and I am a born multitasker, so I also
secrete a different hormone you may not have heard of before; it’s called
glucagon. Glucagon is a hormone that breaks down the glycogen I help store in
the liver, muscles, or adipose tissue, so your cells can keep on eating even when
you’re not or when you are sleeping. Let me show you how this works. Let’s say
lunch is over now and it’s time to catch a few Z’s.
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Biology
Glucose Molecules: Only two Glucose Molecules are moving around in the
bloodstream.
Pancreas: What’s Up? The blood glucose level is too low! We need more Glucose
Molecules in the blood (releases two Glucagon Red Wizards into the blood).
Glucagon Red Wizard: The Glucagon Red Wizard goes over to the muscles and
lightly taps glycogen on the shoulder with a wand and says, “Transform!” (Switch
labels). This changes glycogen back to glucose.
Glucose: The two Glucose molecules move out of the muscles and back into the
blood. Since there are four glucose molecules in the blood now, everything is in
balance again.
Pancreas, Glucose, and Glucagon Red Wizard perform the Glucagon Rap.
Glucagon, glucagon
For in between meals and until dawn
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Biology
Formative assessment: Assume the blood glucose level is high. Place the cards in
order to show the sequence of events. Begin with the pancreas.
Pancreas
secretes
insulin.
Blood glucose
level rises
inhibiting
glucagons
secretion.
Glucose is
converted to
glycogen. Glucose
is also transported
to cells.
Blood glucose
level drops,
which inhibits
insulin secretion.
Pancreas secretes
glucagon
Breakdown
glycogen to
glucose; glucose
released from
cells.
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Biology
Blood Glucose Rubric
Accuracy
Label
Drawing
Revise and
Resubmit
Fewer than 70%
of the assigned
details are
present OR
most details are
difficult to
identify.
Less than 70%
of the items that
need to be
identified have
labels OR it is
not clear which
label goes with
item.
Less than 70%
of the assigned
structures are
drawn AND/OR
labeled
accurately.
70-79 Points
80-89 Points
90-100 Points
70%-79%) have
been added. A
few details are
difficult to
identify.
Almost all
assigned details
(at least 80-89%)
have been added.
The details are
clear and easy to
identify.
Almost all items
(80-89%) that
need to be
identified have
labels. It is clear
which label goes
with which
structure.
80-89% of the
assigned
structures are
drawn accurately
and are
recognizable. All
assigned
structures are
labeled
accurately.
All assigned
details have been
added. The
details are clear
and easy to
identify.
Most items (7079%) that need
to be identified
have labels. It
is clear which
label goes with
which structure.
Every item that
needs to be
identified has a
label. It is clear
which label goes
with which
structure.
70% -79% of
90% or more of
the assigned
the assigned
structures are
structures are
drawn
drawn accurately
accurately and
and are
are
recognizable. All
recognizable.
assigned
94-85% of the
structures are
assigned
labeled
structures are
accurately.
labeled
accurately.
This rubric was created using information from the following website:
http://rubistar.4teachers.org/index.php
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Biology
REVIEW THIS LAB
Investigation of Plant Hormones
http://www.biologycorner.com/worksheets/planthormones.html
Introduction: Both plants and animals produce hormones that can regulate
growth. Gibberellins are a group of plant hormones that affect growth. The
effects of these hormones were first observed in the 1920s in rice plants
that were attacked by a fungus, these rice plants grew unusually tall.
Scientists isolated the substance responsible for the growth ( Gibberala
fujikuroi ). Gibberellic acid is derived from this chemical and is used to
make plants grow taller.
Question: What is the effect of gibberellic acid on the growth of
normal and dwarf pea plants?
Procedure
Little Marvel and Alaska
Peas, and Gibberellic
acid can be purchased
from biological supply
companies (such as
Wards or Carolina)
First, take 8 pea seeds and set them in a petri dish
with a paper towel on both the base and the lid.
Wet the paper towels and leave undisturbed until
germination occurs. You may need to re-wet the
paper towels if they become dry. (Make another
petri dish as a spare, in case something happens with your first batch)
After germination - record root and shoot length for each seedling. . After
approximately 1 1Ú2 weeks, transplant seeds to containers:
Apply Gibberellic acid to seedlings by using a cotton swab - apply to the
leaves and the shoot tips of the seedlings after they have been
transplanted. You will need 4 pots each containing 2 -4 seedlings each (if
one of them dies, you can still use the data from the alternate.)
Record your data over a period of 8-10 days. You may also check with
other groups to get an average for each treatment. You will need to turn in
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Biology
your data tables and your graphs of the data when you turn in your lab
report. You can use toothpicks and paper to create tiny "flags" so that you
can tell each seedling apart and record the data accurately. Work with
your group to develop a comprehensive data table.
Analysis (To be answered in your lab report)
1. Why was water applied to the 1st and 3rd pots?
2. Based on the graphs, which group had the fastest rate of growth?
3. Compare the growth of the Little Marvel Pea plants and the Alaska Pea
plants with and without the treatment of gibberellic acid.
4. Suggest real world applications for gibberellic acid.
Use the Lab Report Template to write your lab report.
Further Experiments
As a group, choose ONE of the following experiments, conduct it over a
two week period and submit a lab report. You will have Little Marvel Peas
and Alaskan peas to work with.
A. Gardeners often pinch off the stems of plants to enhance the plants'
growth. The pinching off is related to the production of certain hormones.
Design an experiment that would show the effect of pinching back the
stem tips.
B. In the first experiment you applied the hormone to the shoots and
leaves of the plant. Design an experiment to determine whether this
hormone can also be absorbed by the roots and have the same effect.
C. Do fully grown plants respond to the presence of gibberellic acid? (Use
your control groups from you last experiment to design this experiment)
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Biology
CHECK SHEET FOR INDEPENDENT INVESTIGATION
I.
Stating a problem to investigate
Problem phrased as a research question
If…then hypothesis statement
5
II.
Develop a procedure to compare baseline heart and
respiration rates to an after exercise heart and respiration
rates.
All steps in sequential order and reproducible
Multiple trials indicated
Materials are appropriate and described
III.
IV.
V.
VI.
Gathering respiration and heart rate data
Data organized in table or chart
Data has a title
Labels for manipulated & responding variables
Units are stated
Multiple trials, totals and averages are included
Graphing data
Appropriate graph type used
Appropriate scale, range, and interval are used
Graph has a title
Descriptive label for variable on the x-axis and
responding variable for the y-axis
Graphed data matches data collected
Units indicated for each axis
Data analysis
Results from graph clearly stated
Inferences made about results
15
20
20
Conclusion
Conclusions based on results and inferences
Hypothesis is restated
Hypothesis is accepted or rejected
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Biology