Circadian Rhythms

Flashcards covering key concepts of circadian rhythms as discussed in the lecture.

What is the definition of circadian rhythm?

A biological process that displays an endogenous, entrainable oscillation of about 24 hours.

Where is the master clock of the circadian rhythm located in mammals?

In the suprachiasmatic nucleus of the hypothalamus.

What is a zeitgeber?

An external signal that helps synchronize the circadian rhythm with the environment.

What is the primary zeitgeber for circadian rhythms?

Light.

What effect do false light cues have on circadian rhythm?

They can modify the length of the circadian rhythm.

What does the pineal gland produce that promotes sleep?

Melatonin.

How does the circadian rhythm tend to change in the absence of zeitgebers?

It tends to lengthen slightly, averaging around 24 hours 11 minutes.

What are the two categories of sleep patterns mentioned?

Monophasic and polyphasic sleep.

What is polyphasic sleep?

Sleeping multiple times per day for shorter periods of time.

What are some key molecular components of the circadian clock?

Clock genes, such as Per (Period) and Cry (Cryptochrome).

Besides light, what are some other examples of zeitgebers?

Social cues, exercise, meal times, and temperature.

What are some common consequences of a disrupted circadian rhythm?

Sleep disorders, metabolic issues, cognitive impairment, and mood disturbances.