Circadian Physiology

1. A rhythm that continues even in the absence of external cues.
3. The lowest point of a circadian cycle, opposite of acrophase.
8. An individual’s natural preference for sleep and wake times (e.g., night owl vs. early bird).
9. A state when internal biological rhythms are out of sync with external time cues.
12. The ability of a circadian rhythm to remain stable across different temperatures.
14. A method used to track sleep-wake cycles based on movement.
19. A condition where a person’s sleep-wake cycle is shifted later than normal.
20. The process that regulates sleep pressure and compensates for sleep loss.
23. Scientist who studied circadian rhythms in flying squirrels.
24. A behavioral measure used to study circadian rhythms in animals.
25. A "time giver"; environmental cue (like light) that entrains circadian rhythms.

2. The brain region that acts as the body's master circadian clock.
4. A condition where a person’s sleep-wake cycle is shifted earlier than normal.
5. A biological rhythm that persists in the absence of environmental time cues.
6. Disorder A circadian disruption caused by working irregular hours, leading to sleep problems.
7. French scientist who conducted the first known experiment in chronobiology in 1729.
10. The Nobel Prize-winning gene identified in fruit flies that regulates circadian rhythms.
11. The light/dark schedule that determines diurnal or nocturnal behavior.
13. The peak of a circadian rhythm is called this.
15. The three scientists awarded the Nobel Prize for their work on the biological clock.
16. A change in the timing of a circadian rhythm, often caused by external stimuli.
17. The hospital affiliated with circadian rhythm researcher Chuck Czeisler.
18. The hormone produced by the pineal gland that helps regulate sleep cycles.
21. The bioluminescent organisms Woody Hastings studied for circadian research.
22. The ability of a biological rhythm to synchronize with external cues like the light-dark cycle.