Step One
Lab Three is about homeostasis a state of balance in the body. The balance is maintained through a series of negative feedback mechanisms that keep the body functioning normally.

Instructions: Click on the following links to view the Pre-Lab Lecture Tutorials on basic concepts of Homeostasis.

Lab 3 Tutorial by Mitch Albers

• Introduction to Homeostasis
  • Negative Feedback (Blood Pressure)
  • Neagtive Feedback (Body Temperature)
  • Positive Feedback (Labor during Child Birth)
• Another intro to the concept of Homeostasis
• Homeostasis Tutorial
• Negative Feedback and the endocrine system

Please refer to chapter 4, p.70 in Sylvia S. Mader's Human Biology texbook for more details on the Structure and Function of Cells.

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Step Two
This "Hands On" lab experiment is titled, "Human Homeostasis". In this laboratory, the interactive simulation of human homeostasis provides students the opportunity to explore how our body maintains a stable internal environment in spite of of the outside conditions, within certain limits. This simulation allows students to investigate a phenomenon that may in real life, be dangerous to humans. Students are asked to regulate the internal body temperature of an individual using clothing, exercise, and perspiration. Click here to review homeostasis of body temperature.

Click here to download and print the Student Exploration Sheet. The Student Exploration Sheet will guide you through the simulation, including a short prior knowledge piece providing information on how to use the simulation and introductory questions.

Don't Panic...I understand your not a PhD physiologist, but the focus in this excercise will be to understand how the body maintains homeostasis in terms of regulating body temperature.

Please go to the following links to get all the instructions for doing your experiments.

EXPERIMENT ONE:

Step One: Go to the "Gizmos" website homepage and select the "Free Trial" button in the upper right menu (https://www.explorelearning.com)

• Register a free student "Free Trial" account for 30 day access to the Gizmos website.
  • You'll be asked to enter your Email address and Gizmos will send you an Email message with a link to activate your free trial account.
  • You'll be asked to compete your account information. be sure to select the blue "Home User Trial" button for trial type.
    • Under Teaching Info select:
      • State: "Minnesota"
      • Grade Levels "Grades 9-12"
      • Title "Tutor"
    • After you set up your account you'll land on a page of sample Gizmos activites. Select the "Find Gizmos" button from the top menu bar and enter the search term "Human Homeostasis".
    • A list of new Gizmos interactive activites will show up. Scroll down the page to the the "Human Homeostasis Exercise" and select the "Launch Gizmos" link (as shown in the image below).

• • • When you launch the Human Homeostasis Gizmos link you'll come to the interactive module that looks like this screenshot:

Step Two: Click on this link to Download and then print out the Human Homeostasis Student Exploration Sheet:

• A.) Two separate activities are included: one that helps you understand the how each external factor affects initial body temperature and another that allows students to explore effects on body temperature after one hour. In the second portion of the interactive simulation students try to maintain a stable body temperature when the factors are changed. Students choose the factors of exercise level, sweat level, body position, clothing, and nutrients in terms of both water and food to maintain homeostasis. The simulation generates data tables and graphing during specific time intervals of outside temperature and body temperature. Students may also alter the outside temperature as part of the simulation. Students adjust the exercise level, amount of clothing, and sweating levels. Water level, sugar level, and fatigue level are influenced by the students’ choices and are illustrated by bar graphs and line graphs.
  • This interactive simulation provides students with a strong introduction to how body systems interact as the simulation illustrates how to maintain body temperature, sugar level and fatigue level and students are made aware of the consequences of not maintaining those levels. The importance of water and food are also emphasized. Students can rerun the simulation making different choices to determine the effects on homeostasis.
• B.) Using the Student Exploration: Human Homeostasis Sheet and the Gizmos Human Homeostatis interactive module complete the following:
  1. 1. Prior Knowledge Questions
     2. Activity A: Body Temperature
     3. Activity B: Thermoregualtion
        • Besure to answer Questions 6 and 7.
        1. • Think and Discuss - Can you identify other methods used to maintain body temperature?
           • Critique - Can you identify limitations of this simulated exercise?
           • Be sure to complete the "Assesment Questions" located below the Human Homeostasis interactive module.
             • Select the "Check Answers" option.

  Note: Please keep your responses and this sheet in preparation of the Lab 3 Quiz you'll be taking in D2L and for the Wiki Assignment for Lab 3. You do NOT need to turn this sheet into your intructor.

Experiment Two: Step Test (Do this at home)

• Now try a real test on your own cardiovascular system!
• Take your resting pulse rate while sitting down in a chair by following these simple directions:
• Your heart rate can be taken at any spot on the body at which an artery is close to the surface and a pulse can be felt. The most common places to measure heart rate using the palpation method is at the wrist (radial artery) and the neck (carotid artery). Other places sometimes used are the elbow (brachial artery) and the groin (femoral artery).
  
  To take your resting heart rate at the wrist, place your index and middle fingers together on the opposite wrist, about 1/2 inch on the inside of the joint, in line with the index finger.  Feel for a pulse.  When you find a pulse, count the number of beats you feel within a one minute period.  You can estimate the per minute rate by counting over 30 seconds and doubling the result.
  
  You should always use your fingers to take a pulse, not your thumb, particularly when recording someone else's pulse, as you can sometimes feel your own pulse through your thumb.
   
• Record your resting Pulse Rate: _____ /minute
   
• Step Test - Go to a stairway and have a watch or clock in view to keep track of time. Step up and down on one step at a constant rate for 3 minutes. After the three minutes, sit down in a chair and take your pulse rate again.

• Record your Pulse Rate after the step test : _____ /minute
   
• Continue measuring your pulse rate until your pulse returns back to your resting rate (recovery time). Measure how long it takes your pulse rate to return back to normal.
   
• Record the time (recovery time) in minutes: _____
   
• Using your knowlege and experience from the CardioLab what is happening to your heart when your exercising during the step test?
   
• How did your pulse rate return to normal?
   
• Explain how homeostasis is involved.

Reference: Harvard Step Test

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Step Four

Instructions: Test your knowledge on homeostasis.

Practice Quizzes

• Homestasis Quiz
• Homeostasis Quiz to Tutorial in Step One
• Homeostasis Quiz

When you have completed taking the practice quizzes you are then ready to take the LAB 3 QUIZ in D2L. Please check the course syllabus to make sure that you complete the lab quiz by the scheduled due date. Select the following link to go to D2L:

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