Sleep

Question 1

What structure regulates circadian rhythms?

Answer 1

The suprachiasmatic nucleus (SCN) of the hypothalamus.

Question 2

Name the major stages of sleep.

Answer 2

NREM (stages 1–3) and REM.

Question 3

What characterizes REM sleep?

Answer 3

Rapid eye movements, vivid dreaming, muscle atonia, brain activity similar to wakefulness.

Question 4

What is the function of melatonin?

Answer 4

Regulates sleep-wake cycles; secreted by the pineal gland, increases in darkness.

Question 5

Which neurotransmitters are involved in promoting wakefulness?

Answer 5

Orexin (hypocretin), norepinephrine, histamine, and acetylcholine.

Question 6

What are the EEG characteristics of each sleep stage?

Answer 6

NREM: slow waves (delta) in stage 3; REM: low-voltage, fast activity similar to wakefulness.

Question 7

What is sleep homeostasis?

Answer 7

The balance between sleep need and sleep duration; controlled by adenosine accumulation and circadian rhythm.

Question 8

Which brain areas promote sleep?

Answer 8

Ventrolateral preoptic nucleus (VLPO) inhibits arousal systems to promote sleep.

Question 9

What is the function of REM sleep?

Answer 9

Associated with memory consolidation, emotional regulation, and neural development.