Chapter 9- Sleep Flashcards
Endogenous circannual rhythms
Internal mechanisms that operate on an annual or yearly cycle
Birds migrating
Endogenous circadian rhythms
Internal mechanisms that operate on approximately 24 hour cycle
Purpose is to keep our internal workings in phase with the outside world
Zeitgeber
Any stimulus that resets the circadian rhythms
Ex: light, noise
Suprachiasmatic nucleus (SCN)
Part of the hypothalamus and the main control center of the circadian rhythms of sleep and temperature
Pineal gland
An endocrine gland located posterior to the thalamus
Melatonin
A hormone that increases sleepiness or readiness for sleep
Coma
Low brain activity that remains fairly steady
Person shows little respond to stimuli
Extended period of unconsciousness caused by head trauma, stroke, or disease
Vegetative state
Alternates between periods of sleep and moderate arousal but no awareness of surrounding
What happens before stage 1 of sleep?
Alpha waves are present and state of relaxation begins
8-13 HZ
Stage 1
Sleep has just begun
Irregular, jagged, low voltage waves
Brain activity begins to decline
Stage 2
Sleep spindles: 12-14 HZ waves during a burst
K-complex: sharp high altitude negative wave followed by a smaller, slower positive wave
Theta wave: 4-7 HZ
Stage 3 and 4
Slow wave sleep
Large amplitude wave
Slowing of heart, breathing rate and brain activity
Delta waves: 0-4 HZ
Rapid eye movement (REM)
Periods of rapid eye movements during sleep
Paradoxical sleep
Deep sleep in some ways, but light sleep in other ways
After about an hour, the person begins ?
To cycle back through the stages from stage 4 to stages 3 and 2 and than REM
Reticular formation
Part of the Midbrain that extends form the medulla to the forebrain and is responsible for arousal
Pontomesencephalon
Stimulation here awakens sleeping individuals and increases alertness in those already awake
Part of the midbrain that contributes to cortical arousal
Locus coeruleus
A small structure in the pons whose axons release norepinephrine to arouse various areas of the cortex and increase wakefulness
Insomnia
Sleep disorder associated with inadequate sleep
Caused by noise, stress, pain medication
Sleep apnea
Sleep disorder characterized by the inability to breathe while sleeping for a prolonged period of time
Causes sleepiness during the day, impaired attention, depression, heart problems
Narcolepsy
A sleep disorder characterized by frequent periods of sleepiness
Muscle weakness
Sleep paralysis
Hallucinations
Periodic limb movement disorder
Repeated involuntary movement of the legs and arms while sleeping
Occurs during NREM sleep
REM behavior disorder
Vigorous movement during REM sleep
Acting out dreams
Damage to the pons
Night terrors
Experiences of intense anxiety from which a person awakens screaming in terror
Functions of sleep?
Energy conservation
Restoration of the brain and body
Memory consolidation
Functions of REM
Discard useless connections
Learned motor skills may be consolidated
Activation synthesis hypothesis
Dreams begin with spontaneous activity in the pons which activates many parts of the cortex
Clínico anatomical hypothesis
Dreams are similar to thinking just under unusual circumstance
