Biological Rhythms and Sleep

These flashcards cover key concepts around biological rhythms, sleep stages, hormonal regulation, and their impact on mental health.

What are biological rhythms?

Biological rhythms are regular fluctuations in bodily processes, including sleep/wake patterns, body temperature, and hormone levels.

What is a circadian rhythm?

Circadian rhythms are biological rhythms that fluctuate about every 24 hours.

What is an example of an infradian rhythm?

The human menstrual cycle is an example of an infradian rhythm.

What happens in the absence of external time cues to circadian rhythms?

Circadian rhythms do not follow an exact 24-hour cycle and may show a slightly longer free-running period.

What resets or alters circadian rhythms?

Light acts as a dominant zeitgeber, followed by other factors like exercise, environment temperature, food intake, and social cues.

What is the role of the suprachiasmatic nucleus (SCN)?

The SCN serves as the biological master clock, maintaining circadian rhythms to a 24-hour period.

What happens to circadian rhythms when the SCN is removed?

Removal of the SCN results in the absence of circadian rhythms, demonstrated through free-running rhythms in constant darkness.

What are retinohypothalamic path cells sensitive to?

These cells are sensitive to blue light and respond independently of rods and cones.

What is the function of melatonin?

Melatonin is a hormone that regulates sleepiness and is secreted by the pineal gland.

How does melatonin affect circadian rhythms?

Melatonin can phase-advance the internal sleep/awake clock when taken at the right times.

What is the typical percentage of REM sleep for a young adult?

Approximately 20% of a young adult's sleep is in REM.

What characterizes rapid eye movement (REM) sleep?

REM sleep is marked by active EEG with small-amplitude, high-frequency waves and vivid dreams.

What are night terrors?

Night terrors are sudden arousals from stage 3 sleep accompanied by activation of the autonomic nervous system.

What role does the forebrain play in sleep?

The forebrain is crucial for Slow Wave Sleep (SWS) through GABA transmission.

How are ADHD and sleep related?

There is a strong association between sleep-related issues and ADHD symptoms, affected by medication.