Unit 2-8 Flashcards
Biological rhythms
Regular, fluctuations in any living process
Circadian
24 hour, sleep/wake, body temperature
Ultradian
Faster/ shorter than a day (activities, hormone release, feeding behavior)
Infraradian
Longer than one day (menstrual cycle, seasonal depression/ disorders)
What help set rhythms
Duration of light exposure
Light must reach the rhythm centers of the brain (through eyes or something else)
- Birds and amphibians have pineal gland
- Mammals have melanopsin in photoreceptors, project to SCN (suprachiasmatic nucleus) through retinohypothalamic tract
How light and molecular clock work together
- clock/ cycle bind together, enter nucleus and bind to DNA, increases production of Period and Cryptochrome genes
- Period and Cryptochrome bind together and stop clock/ cycle from entering nucleus
- glutaminergic inputs from retinohypothalamic tract synchronize the gene expression to loop light
Stage of sleep
Stage 1: Non rem, heart and breathing slow
Stage 2: non rem, brain shows spindle patterns
Stage 3: non rem, brain shows delta waves (slow sleep waves - SWS)
REM sleep: brain looks like it is awake, eyes move quickly, muscle atonia (body doesn’t move)
Sleep changes with age
- REM is more prevalent in infants and young children, declines as we get older
- sleep per day declines
Total sleep deprivation (fatal familial insomnia)
- Prion protein mutation (mad cow disease) prevents sleep
- Lesion in thalamus and frontal cortex
- Patients die cause immune system shuts down
Why do we sleep? (4)
- energy conservation
- niche adaptation (maximize opportunities and avoid danger)
- body and brain restoration (growth hormone, lifespan, glymphatic system cleans itself)
- memory consolidation
Neural system that underlie sleep (4)
- Forebrain (slow wave sleep)
- Pons (trigger REM sleep)
- Reticular formation (wakes us up)
- Hypothalamus (control center)
Narcolepsy
- insane sleep attacks into REM that last 5-30 min, occur anywhere/time
- cataplexy - sudden loss of muscle tone
- due to loss of neurons in hypothalamus that produce the peptide orexin
Sleep disorders continued (5):
- Sleep paralysis - unable to move before or after sleep, hallucinating
- Night terrors - arousal from stage 3 SWS marked by intense fear and crushing feeling in chest, can’t recall dream
- Sleep enuresis - bed wetting
- Somnambulism - sleepwalking
- REM behavior disorder - not paralyzed during REM sleep, bodies act out dreams
Insomnia
- Unable to sleep
- onset - can’t fall asleep
- sleep maintenance - can’t stay asleep
- caused by physical or mental conditions (sleep apnea, anxiety, drugs)
