Circadian Rhythms and Melatonin

How many hours does the human internal clock run off of?

25 hours--this is why we need an alarm clock

How are circadian rhythms related to sleep patterns?

Circadian rhythms dictate the patterns that a person sleeps and is awake and can be thrown off by illness, stress, environment stimuli, etc.

What is meant by a biological clock or a circadian rhythm?

Include the idea that a biological clock is an internal system that relates to human sleep/wake cycles in a 24 hour period. This internal clock is entrainable meaning it is influenced by light which signals a melatonin release thus making a person feel sleepy.

What causes jet lag?

Jet leg is described as desychronization between our internal and external clocks. When a person follows a fairly consistent sleep/wake cycle, the internal body clock becomes aligned with the surrounding day/night signals. When traveling, the environmental cues are suddenly out of synch with an individual's internal body clock. The result is jet lag where a person can feel overtired, disorientated, moody, dizzy, etc. It takes several days to weeks to fully recover from jet lag depending on the length of the trip and the difference in the time zones.

What role does melatonin play in sleep patterns?

Melatonin is a naturally occurring hormone replaced by the brain to make us feel sleepy. It is released in response to the onset of darkness.

How many hours of sleep per night do teenagers need to be alert as possible when awake?

Nine or more hours of sleep a night

What is the SCN?

The circadian clock is located in the SCN which controls the time of melatonin release and regulates the biological clock