TEKS 7.9 A

TEKS 10 A & B, 11AEndocrine System Feedback Systems

TAKS Objective 2 – The student will demonstrate an understanding of living systems and the environment.

TEKS Science Concepts 10 A & BThe 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 AThe 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

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TEKS 7.9 A

For Teacher’s Eyes OnlyTeacher 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

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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 KnowledgeStudents 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

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.

EXPLOREExplore 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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Endocrine System

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 poster-size 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.

EXPLAINComplete 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

ELABORATEStudents should complete the Investigation of Plant Hormones laboratory activity. Students will better understand human hormones by studying plant hormones that stimulate and inhibit growth.

EVALUATE1. 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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BiologyTAKS Objective 2 page 7

Biology

The Endocrine SystemDirections: Match the correct endocrine gland with its function. Label the picture correctly.

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Biology

The Endocrine Glands and Functions

GLANDS

Pineal gland

Pituitary gland

Thyroid gland

Thymus

Adrenal gland

Pancreas

Ovary

Testis

FUNCTIONS

releases a hormone,which is involved in rhythmic activities, suchas daily sleep-wake cycles.

produces a hormonethat regulates metabolism

produces two important hormones that regulatethe level of glucose in the blood.

produces testosterone, whichis responsible for sperm productionand the development of male secondarysex characteristics.

often called the master gland; produceshormones that regulate manyof the other endocrine glands.

releases chemicals into the bodywhich helps it deal with stress

produces female hormones estrogen and progesterone required for development of secondary sex characteristicsand for the development of eggs.

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Biology

releases a hormone, whichstimulates T-cell development.Major player in the immune system

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THE RISE AND FALL OF GLUCOSEAct 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 InsulinStoring sugar is so much funMuscles, 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.

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

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.

Glucose is converted to glycogen. Glucose is also transported to cells.

Blood glucose level drops, which inhibits insulin secretion.

Pancreas secretes glucagon

Blood glucose level rises inhibiting glucagons secretion.

Breakdown glycogen to glucose; glucose released from cells.

Blood Glucose Rubric

Revise and Resubmit

70-79 Points 80-89 Points 90-100 Points

Accuracy Fewer than 70% of the assigned details are present OR most details are difficult to identify.

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.

All assigned details have been added. The details are clear and easy to identify.

Label Less than 70% of the items that need to be identified have labels OR it is not clear which label goes with item.

Most items (70-79%) that need to be identified have labels. It is clear which label goes with which structure.

Almost all items (80-89%) 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.

Drawing Less than 70% of the assigned structures are drawn AND/OR labeled accurately.

70% -79% of the assigned structures are drawn accurately and are recognizable. 94-85% of the assigned structures are labeled accurately.

80-89% of the assigned structures are drawn accurately and are recognizable. All assigned structures are labeled accurately.

90% or more of the assigned structures are drawn accurately and are recognizable. All assigned structures are labeled accurately.

This rubric was created using information from the following website: http://rubistar.4teachers.org/index.php

REVIEW THIS LAB

Investigation of Plant Hormoneshttp://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

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 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

Little Marvel and Alaska Peas, and Gibberellic acid can be purchased from biological supply companies (such as Wards or Carolina)

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)

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

15

III. 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

15

IV. 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

20

V. Data analysis Results from graph clearly stated Inferences made about results 20

VI. Conclusion Conclusions based on results and inferences Hypothesis is restated Hypothesis is accepted or rejected

25