Chapter 8- Wakefulness and Sleep

Flashcards about Wakefulness and Sleep

What are endogenous circannual rhythms?

Internal mechanisms that operate on an annual or yearly cycle.

What are endogenous circadian rhythms?

Internal mechanisms that operate on an approximately 24-hour cycle.

What is a zeitgeber?

Stimulus that resets the circadian rhythm.

What are some examples of zeitgebers?

Light, exercise, meals, and temperature.

What is jet lag?

The disruption of circadian rhythms due to crossing time zones.

What happens to our circadian rhythms when traveling west?

Our circadian rhythms are phase-delayed.

What happens to our circadian rhythms when traveling east?

Our circadian rhythms are phase-advanced.

What is the suprachiasmatic nucleus (SCN)?

The main control center of the circadian rhythms of sleep and temperature.

Where is the SCN located?

Above the optic chiasm and part of the hypothalamus.

What is the retinohypothalamic path?

A small branch of the optic nerve that travels directly from the retina to the SCN.

What is melanopsin?

The photopigment in ganglion cells that respond directly to light.

What do Period genes do?

Produce proteins called PER.

What do Timeless genes do?

Produce proteins called TIM.

What does the SCN regulate?

Regulates the pineal gland, which releases melatonin.

What does melatonin do?

Promotes sleep; starts rising 2-3 hours before bedtime.

What is a coma?

Extended period of unconsciousness characterized by low brain activity that remains fairly steady.

What is unresponsive wakefulness syndrome?

Person alternates between periods of sleep and moderate arousal but no awareness of surrounding.

What is a minimally conscious state?

One stage higher than a vegetative state marked by occasional brief periods of purposeful action and limited speech comprehension.

What is brain death?

No sign of brain activity and no response to any stimulus.

What is stage 1 sleep characterized by?

Dominated by irregular, jagged, and low-voltage waves.

What is Stage 2 sleep characterized by?

Sleep spindles and K-complexes.

What is slow-wave sleep (SWS) characterized by?

EEG recording of slow, large amplitude wave.

What is the reticular formation?

Part of the midbrain that extends from the medulla to the forebrain and is responsible for arousal.

What is the pontomesencephalon?

A part of the reticular formation in the midbrain that contributes to cortical arousal.

What is the locus coeruleus?

A small structure in the pons whose axons release norepinephrine to arouse various areas of the cortex and increase wakefulness.

What does the hypothalamus contain?

Neurons that release histamine to produce widespread excitatory effects throughout the brain.

What releases orexin?

Lateral and posterior nuclei of the hypothalamus.

What are PGO waves?

Waves of neural activity detected first in the pons, then in the lateral geniculate of the hypothalamus, and then the occipital cortex.

What is insomnia?

A sleep disorder associated with inadequate sleep.

What is sleep apnea?

A sleep disorder characterized by the inability to breathe while sleeping for a prolonged period of time.