EXAM 3 CIRCADIAN RHYTHMS 9 1 9 3 Define circadian rhythm and zeitgeber Know examples of each Circadian rhythm Rhythms that last about a day humans 24 2 hours Examples waking and sleeping hormone secretion Zeitgeber stimulus that resets the biological clock Examples temperature exercise noise What is the purpose of endogenous rhythms To prepare for changes in environment before they occur sunrise sunset What are jet lag and shift work and what are some effects of these situations on people Jet lag endogenous rhythm doesn t match external time easier to travel west Shift work people who work out of synch with regular sleep wake cycle Effects some memory impairment toxic to hippocampus stress What is the significance of the suprachiasmatic nucleus SCN Main control center for sleep and temperature circadian rhythms What is the behavioral result of a lesion of the SCN 1 2 3 Totally disrupt activity cycle How did brain transplants help prove the role of the SCN Brain transplants in mice prove SCN contains clock because transplanted the brain of a 20hr sleep cycle mouse into a 24 hr cycle mouse and the cycle changed to 20 hrs 4 5 light What are some genes and proteins involved in sleep and how are they involved Genes period timeless clock Proteins per tim clock Small amounts in morning and increase as day goes on Cycle begins again in morning Light disrupts process What is the retinohypothalamic pathway Projection that goes directly from the retina to the SCN providing it with info about In what way does it contribute to circadian rhythms Light proteins called mleanopsin resets clock even in blind rats From what retinal cells does it project and where does it go From specialized neurons in retina and turn on and off slowly so respond to overall average amount of light How do humans respond to melatonin ie does it make us sleepy or awake How is melatonin involved in circadian rhythms Hormone released for sleep cycle What structure makes releases melatonin Pineal gland When is it released 2 3 hours before bedtime What brain structure responds to melatonin 6 1 2 Feeds back to SCN Makes tired SLEEP 9 1 9 3 Energy conservation Restoration Memory We discussed 3 possible functions of sleep in general know those We also discussed possible functions of REM sleep know those Important for memory brain development oxygen to corneas rapid eye movement in REM sleep 3 What are the different stages of sleep Stage 1 overall brain activity high but declining Stage 2 brain activity still decreasing see wave forms k complexes which serve to protect a person from being woken up Stage 3 and 4 slow wave sleep Stage 4 thalamus stops relaying sensory info to cortex unless extreme In general what is brain activity like in those stages 1 4 brain activity decreases 3 4 slow waves brain acitivity synchronized In what order do humans move thru these stages during a night of sleep 1 2 3 4 3 2 REM What do heart rate breathing blood pressure and temperature do during the different stages of sleep 1 4 heart rate breathing brain activity decrease What is paradoxical about REM sleep Low voltage high frequency waves mimic light sleep body in almost paralyzed 4 state What neurotransmitters are involved How is it related to dreams Serotonin and ach normally released when awake are released in REM sleep When dreaming what brain areas are very active and which ones are Dreams normally occur in REM 5 inactive Amygdala active Hypothalamus is active Sensory cortex not active Prefrontal cortex not active What is the functional consequence of that for example the prefrontal cortex being inactive leads to poor memory and logic in dreams Amygdala active emotional content of dreams Hypothalamus is active motivations and drives in dreams Sensory cortex not active no sensory info to compete with self generated information hallucinations Prefrontal cortex not active leads to poor memory and logic in dreams What are PGO waves A distinctive pattern of high amplitude electrical potentials associated REM sleep 6 Know understand some common sleep disorders insomnia narcolepsy sleep apnea periodic limb movement disorder restless leg syndrome REM behavior disorder night terrors sleep walking sleep talking Inadequate non restorative sleep Causes Medical disorders pain psychiatric disorders aging INSOMNIA NARCOLEPSY SLEEP APNEA Frequent periods od sleepiness during the day Inability to breathe while sleeping Causes genetics hormones ageing obesity PERIODIC LIMB MOVEMENT Legs kick up once every 20 30 seconds Can cause insomnia REM BEHAVIOR DISORDER Move around vigorously during REM sleep because no paralysis NIGHT TERRORS AND SLEEPWALKING Experiences of intense anxiety from which person awakens screaming in Night terrors and sleep walking usually occur during non REM sleep and terror usually in children 7 As we age what changes about overall sleep and the amount of time spent in REM sleep and what happens to the incidence of sleep disorders Less time sleeping less time in REM sleep More common sleep disorders ORGANIZING AND ACTIVATING EFFECTS OF HORMONES 11 1 Know the 3 classes of sex steroid hormones and their synthesis pathway Know examples of each class ie testosterone is an androgen Androgens testosterone DHT Estrogens estradiol Progestin progesterone 1 2 Know the differences between organizational and activational effects of hormones What are some examples of each type of effect in men and in women ORGANIZING Generally permanent characteristics Reproductive organs Occur most during sensitive periods of development Determine whether brain and body will develop male or female Occur any time in life when a hormone temporarily activates a response Effects last as long as hormone is present generally temporary Includes menstrual cycle in women sexual excitement in men What is the chromosomal difference between males and females Brain Behavior ACTIVATING Reproductive behavior Menstrual cycle 3 Normal female XX Normal male XY Y has SRY XX male with SRY translocation XY female with SRY missing What is the region of the Y chromosome that is important for male development and how why does that trigger male development SRY triggers male development no SRY female development SRY gene cause undifferentiated gonad of a mammal to develop into a testis which then produces testosterone and MIH to direct development towards male pattern What does it mean that the default development pattern is female Added testosterone is what develops a male but without
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