Glossary of terms:
Circadian Rhythm: A natural, internal process that regulates the sleep-wake cycle and other bodily functions over a 24-hour period.
Biological Clock: The internal mechanism responsible for regulating circadian rhythms in living organisms.
Suprachiasmatic Nucleus (SCN): A cluster of cells in the hypothalamus of the brain that acts as the master clock, coordinating the body’s circadian rhythms.
Light-Dark Cycle: The regular pattern of day and night that helps synchronize the circadian rhythm to the external environment.
Melatonin: A hormone produced by the pineal gland that helps regulate sleep-wake cycles; its release is influenced by the SCN and the presence of darkness.
Chronotype: An individual’s natural preference for being active during certain times of the day, such as morning (morning chronotype) or evening (evening chronotype).
Jet Lag: The temporary disruption of circadian rhythms that occurs when a person’s internal clock is out of sync with their new time zone after traveling across multiple time zones.
Shift Work: Employment during non-traditional hours, such as overnight shifts, which can disrupt the natural circadian rhythm and lead to sleep disturbances.
Entrainment: The process by which the body’s internal clock is synchronized or adjusted to match external environmental cues, like light and temperature.
Free-Running Rhythm: When an individual’s circadian rhythm is not synchronized to a 24-hour day, often seen in experiments conducted in constant darkness.
Phase Delay: The shift of an individual’s circadian rhythm to a later time, often associated with staying up late and difficulty waking up early.
Phase Advance: The shift of an individual’s circadian rhythm to an earlier time, often associated with going to bed early and waking up early.
Circadian Disruption: Any disruption or irregularity in the natural circadian rhythm, which can have negative effects on health and well-being.
Zeitgeber: An external cue that helps synchronize the circadian rhythm, with light being the most potent zeitgeber.
Shift Work Disorder: A condition characterized by sleep disturbances and fatigue in individuals who work non-standard hours, such as night shifts.
Ultradian Rhythms: Shorter biological cycles that occur within the circadian rhythm, such as the cycle of alertness and sleepiness that repeats multiple times within a day.
These terms should provide a basic understanding of circadian rhythms and related concepts.