Urinary/Excretory System Feedback Systems

TEKS 10 A & B, 11A

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

$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 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.

5 E’s

MENGAGE

BBC Dialysis Video

http://www.bbc.co.uk/cumbria/videonation/archive/w/dan_whitmore/dialysis/index.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.

NEXPLORE

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:

· (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

· 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.

LELABORATE

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:

TAKS Objective 2 page 1

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

TAKS Objective 2 page 1

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.

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.

áEVALUATE

After constructing the urinary system, students will identify the 4 main structures of the urinary system with 100% accuracy.
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.
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.
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 1

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)

· 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.

Image: http://images.main.uab.edu/healthsys/ei_0273.gif

Kidney Filtration Simulation

Overview:

WRITE AN OVERVIEW OF LAB!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Materials:

· Ring Stand

· Funnel

· Ring

· Cornstarch

· Iodine

· Water

· Yellow Food Coloring

· 2 – 150 ml Beakers

· Filter Paper

· Spoon

Procedure:

1. Set up Filtration System (Ring Stand w/Ring, Beaker 1, Funnel, and Filter Paper)

2. To Beaker 2 Add the Following:

· 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

Data:

Contents / Color Before Filtration / Color After Filtration
Beaker 1 / 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?

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.
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

TAKS Objective 2 page 8

Lachrymal (tear) ducts

Ovaries

Thyroid

Adrenals

Testes

Parathyroids

Islets of Langerhans

Pituitary gland

Liver and intestinal glands

Salivary glands

Thymus

Mammary glands

TAKS Objective 2 page 8

B / I / N / G / O
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