TEKS 10 A & B, 11A
Urinary/Excretory 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
page 1
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:
Excretory/Urinary system - The urinary system has one main function. This vital
function is to preserve homeostasis within the body by maintaining the volume
and composition of body fluids within their normal limits. To do this the urinary
system must rid the body of waste products that accumulate within the body
because of cellular metabolism. The major components of the urinary system are
the kidneys, urethers, urinary bladder, and urethra. Although the urinary system
has a major role in excretion, other organs contribute to the overall excretory
function of the urinary system. The lungs excrete waste like carbon dioxide and
water. The skin rids waste from the body through sweat glands. However, the
major task of excretion falls on the urinary system. If the urinary system fails, the
other organs cannot sufficiently maintain body fluids within their normal limits.
The urinary system uses various methods to regulate the amount of water that is
excreted in the urine to maintain the appropriate fluid level in the body. In
regulating the appropriate fluid level within the body, this system also functions
to maintain a delicate balance of electrolytes and keep the body’s blood at a
normal pH.
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. 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
TAKS Objective 2
page 2
TEKS 7.9 A
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
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.
TAKS Objective 2
page 3
TEKS 7.9 A
Uninary/Excretory System
5 E’s
ENGAGE
BBC Dialysis Video
http://www.bbc.co.uk/cumbria/videonation/archive/w/dan_whitmore/dialysis/inde
x.shtml
Show students the video of thirty-seven -year old Dan Whitmore who has kidney
failure. He has to spend three days a week attached to a dialysis machine. He’s on
the waiting list for a kidney transplant.
EXPLORE
Explore 1
CONSTRUCT THE URINARY SYSTEM
Overview:
Explain to the students that they will make a model of the primary components of
their urinary system. Once finished with this activity students will be able to
identify the structures and order the process of the urinary system through their
model.
Materials Needed:
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(per person) One of each item will be used as a key for their model
Body Diagram see figure 2 blackline masters
2 Small marshmallows
Glue
TAKS Objective 2
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TEKS 7.9 A
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3 Kidney beans
3 Spaghetti pieces (uncooked 1 inch long)
2 Pieces of Cafeteria Straw (1 centimeter long)
Scissors
2 pieces of Red Yarn (3 inches long)
2 Pieces of Blue Yarn (3 inches long)
Explore 2
Kidney Filtration Simulation Lab
Students will participate in a lab activity that will simulate the overall function of
the kidneys.
EXPLAIN
Complete the Excretory PowerPoint presentation with your student with
discussion and the completion of the following questions.
1. How does the body keep from overheating? 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
(open larger) which helps move heat away from the skin. Sweating cools
the body through evaporation.
2. On the other hand, how does the body keep warm? In order for the body
to keep warm, first the sweat glands and blood vessels constrict (become
smaller) to conserve body heat. If the body temperature continues to fall,
the skeletal muscles will shiver to produce heat. Finally, the
decomposition of fat will rev up the metabolic rate and produce heat.
TAKS Objective 2
page 5
TEKS 7.9 A
ELABORATE
Elaboration 1
Exocrine and Endocrine Glands
Students will complete a worksheet that compares the endocrine and exocrine
system
Elaboration 2
Exocrine/Endocrine System BINGO
Provide each student a blank BINGO card (see Blackline Masters).
List the following key terms on the board:
Lachrymal (tear) ducts
Sebaceous glands
Ovaries
Thyroid
Adrenals
Testes
Parathyroids
Kidneys
Pancreas
Skin
Sweat Glands
Pancreas
Islets of Langerhans
Pituitary gland
Liver and intestinal glands
Salivary glands
Thymus
Mammary glands
In any order they chose, have students write the key terms on their BINGO card.
This will prevent any card from being identical and several students’ bingo at the
same time.
TAKS Objective 2
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TEKS 7.9 A
Directions:
1. The teacher will read a definition or give a description of the terms.
2. The students will locate the correct term on their BINGO card and place a
marker on the space.
3. Continue the game until a student calls BINGO.
4. Have the student who called BINGO read back each term and give the correct
definitions in order to win the game.
EVALUATE
1. After constructing the urinary system, students will identify the 4 main
structures of the urinary system with 100% accuracy.
2. After identifying the components of the urinary system with 100%
accuracy, the students will verbally order the process of the urinary system
through their model. A grade of pass/fail will be given.
3. Using the text, class notes, and class discussion the learner will correctly
identify and describes the structures and functions of the urinary system
and provide one limitation of the kidney filtration model. A grade of
pass/fail will be given.
4. Using the text, class notes, and classroom discussion the learner will
demonstrate an understanding of the structures and functions of the
endocrine and exocrine glands correctly matching the structure with its
function while playing endocrine/exocrine bingo. A grade of pass/fail will
be given for participation.
TAKS Objective 2
page 7
TEKS 7.9 A
TAKS Objective 2
page 8
BIOLOGY
Urine for Some Fun!!
Urinary System Model
Overview:
You will be making a model of the primary components of their urinary system.
Once finished with this activity you will be able to identify the structures and
order the process of the urinary system through your model.
Materials Needed: (per person)
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Body Diagram
1 Small marshmallows
Glue
2 Kidney beans
2 Spaghetti pieces (uncooked 1 inch long)
1 Pieces of Cafeteria Straw (1 centimeter long)
Scissors
1 piece of Red Yarn (3 inches long)
1 piece of Blue Yarn (3 inches long)
Procedure:
1. Glue on the kidney beans
2. Cut the yarn pieces in half so that the arteries and veins can go down each
leg.
3. Glue on the arteries and veins.
4. Insert 1 inch spaghetti lengths into the marshmallow at an angle. This will
represent the ureters draining into the bladder.
5. Insert 1 cm piece of straw into the bottom of the marshmallow. This will
represent the urethra.
6. Place glue on the marshmallow only. The spaghetti should be just high
enough to go over the top of the yarn.
7. Make a key with the left over materials in the upper right hand corner of
the paper. Label each component of the urinary system with its function
correctly.
TAKS Objective 2
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BIOLOGY
Image: http://images.main.uab.edu/healthsys/ei_0273.gif
TAKS Objective 2
page 10
BIOLOGY
TAKS Objective 2
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BIOLOGY
Kidney Filtration
Simulation
Overview:
WRITE AN OVERVIEW OF LAB!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Beaker 2
Materials:
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Ring Stand
Funnel
Ring
Cornstarch
Iodine
Water
Yellow Food Coloring
2 – 150 ml Beakers
Filter Paper
Spoon
Funnel
Beaker 1
Procedure:
1. Set up Filtration System (Ring Stand w/Ring, Beaker 1, Funnel, and Filter
Paper)
2. To Beaker 2 Add the Following:
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100ml Tap Water
½ T. Cornstarch
5 Drops of Iodine
10 Drops yellow food coloring
3. Using spoon, stir mixture. Record color of Solution in Beaker 2.
4. Pour Beaker 2 solution into filter, collect filtered solution in Beaker 1.
5. Record color of solution in Beaker 1 and Filter Paper
TAKS Objective 2
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BIOLOGY
Data:
Contents
Beaker 1
Color Before
Filtration
Color After
Filtration
No Contents
Beaker 2
Filter Paper
No Contents
Questions:
1. What does the filter represent?
2. What does Beaker 1 represent?
3. What does the contents of Beaker 1 represent?
4. What does Beaker 2 represent?
5. What does the contents of Beaker 2 represent?
6. What waste does your kidneys get rid of?
7. What are the limitations of this model?
TAKS Objective 2
page 13
BIOLOGY
Kidney Filtration
Simulation
TEACHER KEY
.
Contents
Before
Filtration
Contents
After
Filtration
Color Before
Filtration
Color After
Filtration
Beaker 1
No Contents
Water,
Yellow
Food
Coloring
Nothing in
Beaker
Yellow
Beaker 2
Water,
Starch,
Iodine, Yellow
Food
Coloring
No
Contents
Blackish
Green
Empty
Filter Paper
No Contents
Starch,
Iodine
White
Blackish
Brown
1. What does the filter represent? Kidney
2. What does Beaker 1 represent? Bladder
3. What does the contents of Beaker 1 represent? Urine
4. What does Beaker 2 represent? Arteries and Veins
5. What does the contents of Beaker 2 represent? Blood
6. What waste does your kideys get rid of? Answers will vary.
Urea, Salt, Ions, Water
What are the limitations of this model? Kidneys do not filter all of the water,
nutrients, ions ect… out of blood. Residue left in filter would reenter the
blood. Arteries and veins would not be completely drained of all contents.
TAKS Objective 2
page 14
BIOLOGY
The Exocrine and Endocrine Glands
Exocrine
Endocrine
Glands that secrete liquids into ducts are called ______________________
Those that produce hormones directly into the blood stream are ______________
Read and label the above diagram with the following words
.
Lachrymal (tear) ducts
Islets of Langerhans
Ovaries
Pituitary gland
Thyroid
Liver and intestinal glands
Adrenals
Salivary glands
Testes
Thymus
Parathyroids
Mammary glands
TAKS Objective 2
page 15
BIOLOGY
B
I
N
G
O
FREE
TAKS Objective 2
page 16
BIOLOGY