Transcription

1 We ve seen that organisms have to work hard to maintain optimal conditions for their cells. But how exactly does that work?? What happens if something changes?

2 Measuring Heart Rate

3 Resting Heart Rate As a class lets take our resting heart rate! Count for 20 seconds. Multiply by 3 to get beats per minute.

4 Collect Data Exercise vigorously for two minutes, then without sitting down, take your heart rate. (have a partner watch the time for you while you count!) After resting for 5 minutes, take your heart rate again. Record your data in the Class Data Table. Heart Rate (beats per minute) Resting Immediately After Exercise 5 Minutes After Exercise

5 I WORK OUT!!!! L. Coleman; J. Horton; H. Parker 2014

6 What patterns do you see in the class data? Doodle B Pulse after rest went down to between the resting and after exercise. Resting was in range Goes up after exercise and back down after rest. Almost never goes all the way back down. After exercise is almost double at rest.

7 What questions might a scientist observing these patterns for the first time ask? Doodle C Per. 4 Why does the heart rate go up and down? Why does it go up when you exercise? What controls it? How does it change? Driving Question: Why and how does heart rate change with exercise?

8 Doodle D What does the heart do?

9 Where is the heart pumping blood to? Doodle E

10 Doodle F Why do cells need blood?

11 Which of these materials would a cell Doodle G need more of during exercise? WHY do they need the materials?

12 Which of these would you run out of faster?

13 Doodle H Why does the heart pump faster during exercise?

14 Ticket Out The Door Explain why your heart rate decreases after you stop exercising.

15 Doodle I How does your heart know that it needs to speed up or slow down? Diagram where the information to speed up or slow down your heart rate comes from and where it has to go using arrows on your doodle sheet (don t worry yet about HOW it gets there!) You can add any words or structures that you think may be involved in addition to what is shown on the Doodle Sheet.

16 Lets Find Out! Reading: Control Of Heart Rate Paired Reading Text Mining

17 Putting It All Together On your white board use the manipulatives to create a map of the flow of information that will help you answer our driving question. Begin by mapping the sequence that shows how EXERCISE RESULTS IN AN INCREASE IN HEART RATE (NOTE: you will not use all of the pieces yet). Start with the muscle cells (that is where the need is happening). Use arrows to show the direction information is flowing. To help, use your: Doodle Sheet Reading: Control Of Heart Rate Summary Sheet: Control Of Heart Rate When you finish, leave pieces in place. Then, starting again with muscle cells, map the sequence showing how HEART RATE DECREASES AFTER REST. Have teacher approve when finished.

18 Assessment Draw the diagram you and your group mapped out and your teacher approved on the paper provided. Once you have your diagram, flip the paper over and answer the driving question. This is an individual explanation not a group write.

19 Every organism needs to be able to adjust when something changes its external or internal environment or its needs change. In other words, to maintain HOMEOSTASIS. What are the essential components that allow it to do this? A way to sense the change A way to transmit information A way to process the information A way to transmit orders/directions A way to act on the orders

20 Feedback Diagram Heart rate regulation is an example of how organisms sense environmental change (external or internal), communicate the information to CNS, process it, and then act upon it. This is flow of information ensures the needs of cells are met and is called a FEEDBACK LOOP. On the front of the handout, note below each term which specific component, of the heart rate feedback loop you just described, plays that role. MANY life functions depend on feedback loops. Feedback loops are the way organisms regulate their internal environments in other words, maintain HOMEOSTASIS. The Feedback Diagram Handout gives general terms for the important components of feedback loops.

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22 BRAIN Nerve impulse Blood vessel receptors Heart rate goes up during exercise Nerve impulse HORMONE (Epinephrine) HEART Increased CO2 Muscle cells Beats faster Decreased CO2 Beats slower Blood vessel receptors Heart rate slows after rest. HEART Nerve impulse BRAIN Nerve impulse HORMONE (Acetylcholine)

23 Let s see if we can use the Generic Feedback Loop to map out another phenomenon related to temperature regulation in humans. PHENOMENON: When it gets hot, we sweat. Ø Fill in any of the essential components you know for sure. There will be things you don t know and that s ok just leave them blank for now. Ø Use pencil so you can reuse this diagram for other phenomena in the future.

24 brain When it s hot we sweat. Sweat glands heat Maintain 98.6 body temperature Secretes sweat that cools us as it evaporates.