Biological - NIH Office of Science Education - National Institutes of ...

Sleep, Sleep Disorders, and Biological Rhythms
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).
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?
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