Chapter 4 - Sleep Flashcards
Electroencephalogram (EEG)
A monitoring device that records brain activity.
Non-rapid Eye Movement Sleep (NREM)
Of two main sleep phases, the phase that constitutes three substages, including one with the deepest sleep and slow-wave brain activity.
Stage I Sleep
- Theta rhythm
- Brief transitional phase from wakefulness to sleep.
- Easily disturbed by outside stimuli
- Hard to differentiate between wakefulness and stage one
- Someone who wakes up from this stage may not know they went to sleep
- Eyes may move slowly back and forth
- Muscles relax and may twitch
- Respiration grows more usual than in wakefulness
Stage II Sleep
- Theta rhythm
- 50% of sleep in most adults
- Heart rate slows and body temperature drops
- Sleep spindles and k-complexes
- People are not as responsive as in Stage I sleep
Sleep Spindles & K-Complexs
- Abnormalities in the theta rhythm of stage II sleep
- Brain activity keeping body asleep during occurrences of external stimuli
- Also thought to be involved in memory pocessing
Stage III Sleep
- Slowest stage of sleep
- Most necessary for feeling well rested upon waking
- Restorative functions
- Length increases more with exercise or extended periods without rest
Slow-wave/deep Sleep
Characteristic patterns of electrical brain activity measured by the electroencephalogram (EEG) during the deepest stage of sleep, Stage III.
Rapid Eye Movement Sleep (REM)
One of two main phases of sleep, the final phase of a sleep cycle, when most dreaming occurs and eyes rapidly move under closed eyelids. Brain activity increases to levels equal to or greater than those during waking hours, and blood pressure, respiration, and heart rates rise.
Circadian Rhythm
The body’s sleep-and-wake pattern coordinated by the brain’s master internal clock, the suprachiasmatic nucleus (SCN).
Suprachiasmatic Nucleus (SCN)
Master clock that sets and controls the sleep–wake cycle, sending signals to the brain and to every cell in every organ of the body.
Zeitgebers
Phenomena that can influence and reset the body’s master clock, such as light, activity, exercise, and eating. Light directly affects cells in the eye to send signals directly to the SCN to measure outside light.
Melatonin
A hormone secreted by the pineal gland, especially in response to darkness and in inverse proportion to the amount of light received by the retina. It helps control sleep-and-wake cycles and circadian rhythms.
When is the best time to start a nap?
The best time to start a nap is between 12:30pm and 2pm.
Homeostatic Sleep Drive
Pressure to sleep that builds the longer one is awake, mainly driven by adenosine, a neurochemical that accumulates in the brain. Sleep clears the adenosine, thereby reducing the pressure to sleep.
Adenosine
An important neurochemical that accumulates during wakefulness, and after a prolonged period will mediate sleepiness.
Recommended Sleep Time for Newborns (0-3 months)
14–17 hours (11–19 hours)
Recommended Sleep Time for Infants (4–11 months)
12–15 hours (10–18 hours)
Recommended Sleep Time for Toddlers (1-2 years)
11–14 hours (9–16 hours)
