1. Explain to students that they will use a hypothetical scenario to learn about the physiology and major stages of sleep. You can refer to statement 8 on Master 1.1: “Sleep is time for the body and brain to shut down for rest.” (False.) How did the students respond and why? Is sleep really a time when not much is occurring physiologically? Students can now investigate this idea.
2. Instruct the students to go to http://science.education.nih.gov/supplements/sleep/student and click on “Lesson 2—Houston, We Have a Problem.”

Students are free to navigate through the lesson in whatever sequence they prefer. This means that they may select the astronauts in any order. They may obtain information on the seven physiological parameters for each astronaut in any order they choose.

As an alternative, students may work in teams of three. If they work in teams, have each student analyze data for a different astronaut and discuss the data with their team. This approach ensures that each student is actively participating in the activity.

3. Give each student a copy of Master 2.2, Astronaut Telemetry Evaluation Form.

Explain that they will use it to record their determinations of the astronauts’ sleep states.

4. Ask students to evaluate the data for each astronaut using the information in the Sleep Medicine Reference Manual. Student observations, interpretations, and conclusions should be entered on Master 2.2, Astronaut Telemetry Evaluation Form.

Students should concentrate on their reasoning and indicate which data were useful in making their determinations, which data were not useful, and in both cases, why.

5. After students have had an opportunity to complete their analyses, ask them, What is the state of wakefulness or sleep for each of the three astronauts?

Astronaut Jordan is in REM-stage sleep. Astronaut Rodriguez is in NREM-stage sleep. Astronaut Chen is awake.

Content Standard A:
Students should develop understandings about scientific inquiry.

6. Ask the class, Which physiological data are useful for determining a person’s state of wakefulness or sleep?

Students should conclude that the important parameters for distinguishing between sleep states and wakefulness are EEG, EMG, and EOG. The other four parameters—heart rate, blood pressure, respiratory rate, and body temperature—might be useful in combination with EEG, EMG, and EOG data, but they are not sufficient by themselves. For instance, heart rate increases during REM, but it also may increase with physical activity during wakefulness.

7. Ask students, How can you distinguish between REM and NREM sleep? Between REM and wakefulness? NREM and wakefulness?

The EEG, EOG, and EMG data are reproduced in Figure 2.2. First consider astronaut Jordan. Jordan’s EEG does not appear to represent NREM sleep, although students may have difficulty distinguishing between REM and wakefulness EEGs. However, the lack of muscular activity (EMG) during REM as compared with activity during NREM or wakefulness is the key for determining that this individual is in REM-stage sleep. Rodriguez and Chen can be distinguished from each other based on their EEGs (that is, the increased amplitude and decreased frequency of brain waves during NREM compared with the pattern during REM and wakefulness) and their EOGs (that is, large eye movements during wakefulness as compared with little or no eye movements during NREM).

Figure 2.2. Astronaut data.

Assessment:
Instruct students to answer questions about animal sleep such as a) Do other animals sleep? b) How is their sleep similar to human sleep? and c) How is their sleep different from human sleep? Make available to students relevant information from the Information about Sleep section and from Web sites listed in the Additional Web Resources for Teachers section.

8. Explain to the students that during a normal night’s sleep, we cycle through NREM and REM sleep several times. This cycling is called an ultradian rhythm because the cycle time is less than 24 hours. Conclude the lesson by asking, What can you conclude about sleep from this investigation?

Student comments should reflect that sleep is a dynamic process. This means that the body remains physiologically active with characteristic changes in brain and muscle activity, as well as changes in other physiological parameters. Sleep is not uniform, but rather consists of discrete stages that cycle throughout the night.

1. Introduce the print-based version of this lesson by explaining to the class that they will use a hypothetical scenario to learn about the physiology and major stages of sleep.

You can refer to statement 8 on Master 1.1: “Sleep is time for the body and brain to shut down for rest.” (False.) How did the students respond and why? Is sleep really a time when not much occurs physiologically? Students can now investigate this idea.

2. Show the class the transparency of Master 2.1, Astronaut Scenario, and read it aloud.
3. Give each student a copy of Master 2.2, Astronaut Telemetry Evaluation Form, and single copies of Masters 2.3, 2.4, and 2.5, which contain the telemetry data for the three astronauts.

As an alternative, students may work in teams of three. If they work in teams, have each student analyze data for a different astronaut and discuss it with their team. This approach ensures that each student is actively participating in the activity.

4. Explain that these data are sufficient to tell if an astronaut is awake or asleep, and if asleep, whether in NREM or REM sleep. Further explain that not all of the data may be useful for determining the astronauts’ sleep states.
5. Give each student a copy of Master 2.6, Sleep Medicine Reference Manual. Explain that this is a resource to help them interpret the data they have in front of them and relate it to the astronauts’ sleep states.
6. Instruct students to evaluate the data for each astronaut, using the information in the Sleep Medicine Reference Manual for comparison. Student observations, interpretations, and conclusions should be entered on Master 2.2, Astronaut Telemetry Evaluation Form.
7. After students have had an opportunity to complete their analyses, ask the class, What is the state of wakefulness or sleep of each of the three astronauts?

Astronaut Jordan is in REM-stage sleep. Astronaut Rodriguez is in NREM-stage sleep. Astronaut Chen is awake.

Content Standard A:
Students should develop understandings about scientific inquiry.

8. Ask the class, Which physiological data are useful for determining a person’s state of wakefulness or sleep?

Students should conclude that the important parameters for distinguishing between sleep states and wakefulness are EEG, EMG, and EOG. The other four parameters—heart rate, blood pressure, respiratory rate, and body temperature—might be useful in combination with EEG, EMG, and EOG data, but they are not sufficient by themselves. For instance, heart rate increases during REM, but it also may increase with physical activity during wakefulness.

9. Ask students, How can you distinguish between REM and NREM sleep? Between REM and wakefulness? NREM and wakefulness?

The EEG, EOG, and EMG data are reproduced in Figure 2.2. First consider astronaut Jordan. Jordan’s EEG does not appear to represent NREM sleep, although students may have difficulty distinguishing between REM and wakefulness EEGs. However, the lack of muscular activity (EMG) during REM as compared with activity during NREM or wakefulness is the key for determining that this individual is in REM-stage sleep. Rodriguez and Chen can be distinguished from each other based on their EEGs (that is, the increased amplitude and decreased frequency of brain waves during NREM compared with the pattern during REM and wakefulness) and their EOGs (that is, large eye movements during wakefulness as compared with little or no eye movements during NREM).

Assessment:
Instruct students to answer questions about animal sleep such as a) Do other animals sleep? b) How is their sleep similar to human sleep? and c) How is their sleep different from human sleep? Make available to students relevant information from the Information about Sleep section and from Web sites listed in the Additional Web Resources for Teachers section.

10. Explain to the class that during a normal night’s sleep, we cycle through NREM and REM sleep several times. This cycling is called an ultradian rhythm because the cycle time is less than 24 hours. Conclude the lesson by asking, What can you conclude about sleep from this investigation?

Student comments should reflect that sleep is a dynamic process. This means that the body remains physiologically active with characteristic changes in brain and muscle activity, as well as changes in other physiological parameters. Sleep is not uniform, but rather consists of discrete stages that cycle throughout the night.