Across
- 3. The process of bringing biological rhythms into synchronisation with the environment.
- 5. A biological rhythm which recurs approximately every 24 hours.
- 8. This comes from the German word meaning 'time giver'.
- 10. The dominant zeitgeber in humans.
- 11. A gland in the brain which produces melatonin.
- 12. A sleep disorder involving problems with falling asleep or staying asleep.
Down
- 1. A biological rhythm that occurs less often than once a day.
- 2. The stage of sleep during which the body is paralysed except for the eyes.
- 4. A sleep disorder involving sudden and uncontrollable attacks of sleep.
- 6. A biological rhythm which occurs more often that once a day.
- 7. The hormone which induces sleep.
- 9. A sleep disorder in which a person stops breathing while asleep.