chapter 5 Flashcards
(32 cards)
circadian rhythms
sleep/wake having a rhythm that repeats itself about every 24 hours
zietgebers
environmental cues that reset the biological clock each morning
entrained
synchronized (when sleep and wake periods become entrained to environmental cues)
What controls the circadian rhythm?
the suprachiasmatic nucleus (SCN) of the hypothalamus
what is the function of the suprachiasmatic nucleus of the hypothalamus?
it detects lgiht and entrains dialy biological and bahavior rhythms to the onset of light from the environment
clock genes
set of genes expressed by cells within the SCN whos protein products affect the length of the circadian cycle
what two factors influence the sleep-wake cycle?
circadian factor and homeostatic factor
circadian factor
your biological clock tells your brain that you’re supposed to be asleep or awake
homeostatic factor
the longer youre awake, sleep pressure builds up and tells your brain that you have been many hours without sleep
what happens on an EEG when an individual is drowsy?
neruons fire in synchrony with one another and generate “synchrnized” EEG of high amplitude and low frequency
what happens on an EEG when a person becomes alert?
neurons fire out of synch with one another and generate “desynchronized” EEG with low amplitude and high frequency
what happens to brain waves as a person enter deeper stages of sleep?
the brain waves become progressively higher in amplitude and lower in frequency
What are the brain waves during REM sleep?
brain waves become low in amplitude and high in frequency, resembling brain waves while awake and alert
Hwo often do REM episode occur?
every 90 minutes, growing longer as the night progresses
dreams
occur during REM sleep in the parietal and occipital cortex
brain mechanisms
The thalamus has excitatory projections to the entire cerebral cortex
what makes the cortex wake up?
stimulation of the intralaminar nucleus of the thalamus
how to initiate sleep?
the preoptic area releases GABA to inhibit the waking-on neurons
How are these GABA neurons activated?
The circadian clock (SCN), body temperature, and accumulation of adenosine
what happens during nREM (non-REM sleep)?
reticular neurons in the thalamus inhibit thalamic relay neurons to send sensory info to the cortex
what happens during REM sleep?
neurons in the pons initiate REM sleep, while neurons in the medulla inhibit spinal cord motor neurons
insomnia
inability to fall asleep and/or stay sleep, most common sleep disorder
common causes of insomnia?
stress and anxiety
hypnotic drugs
medications for insomnia
