Ch. 13 - Sleep (FINAL) Flashcards
biological rhythms
learned based on the seasons (earth tilt) and hours of the day (earth rotation)
free-running rhythm
a biological rhythm created completely without external cues
- found to be unreliable
- Aschoff 1978: cycles drift to 25-27 hours
circadian rhythm
runs on 24 hour cycles
disrupting circadian rhythms: 2 disorders
seasonal affective disorder
- wintertime depression, 10% of people in the N. hemisphere
- 5x more common in women
metabolic syndrome:
- combined disorders of weight/insulin abnormalities etc.
- can lead to diabetes and heart failure.
biological rhythms: anatomy & scientist
suprachiasmatic nucleus
- master biological clock
- Richter 1930s used on rats to study circadian rhythm
zietgeber
an external cue that entrains a biorhythm
retinohypothalamic tract, pathway, and light impacts
carries info from retina to SCN.
melanopsin (mRGC): light signal
1. retina
2. optic chiasm (info crosses)
3. L and R SCNs
4. shells of SCNs
5. slave oscillators
sleep processes
S: sleep itself
C: timing of sleep
sleep: W stage
- waking
- beta and alpha waves
- 15-30Hz (low amp, high frequency)
sleep: N1 stage
-drowsy/sleep onset
- beta and theta waves
- 4-7Hz (high amp, low frequency)
sleep: N2 stage
- sleep
- sleep spindles
- 11-16Hz (long and slow)
sleep: N3 stage
- deep sleep
- delta waves
- 1-4Hz
sleep: R sleep
- paradoxical sleep
- sawtooth waves
- slow burts of high activity
- rapid eye movements
- paralysis of muscles
characteristics: N sleep vs. R sleep
N sleep
- low body temp, low heart rate and blood flow, low body weight, increased growth hormones, maintained muscle tone
R sleep
- no body temperature regulation, atonia (no muscle tone), vivid dreams
- 50% of sleep as an infant spent in REM
- less than 10% as an adult
sleep cycles
called N-R sequences
about 90 mins each cycle
avg. 5 cycles per night
