Sensory and Sleep Flashcards
What is circadian rhythm?
24-hour day/day rhythm controlled by the hypothalamus.
Circadian rhythm affects?
-body temp, endocrine fxn, BP, eating habits, digestion, sleepy, etc
-work, alarms, sleep, noise can affect circadian rhythm and the sleep-wake cycle
What 6 main structures in the CNS play a role in sleep?
- Basal forebrain
- Hypothalamus
- Pineal gland
- Thalamus
- Amygdala
- Brain stem
What role does the basal forebrain play in sleep?
Releases adenosine, which supports sleep drive (caffeine blocks action of adenosine)
What role does the hypothalamus play in sleep?
receives info from eyes regarding light exposure → helps determine sleep schedule based on day/night
Secretes hypocretins → promote wakefulness and REM sleep
What role does the pineal gland play in sleep?
secretes melatonin → helps body regulate sleep cycle that correlates w/day and night cycles
Melatonin production increases w/onset of darkness
What role does the thalamus play in sleep?
relays sensory info to cortex for conversion from STM to LTM → occurs during REM sleep
What role does the amygdala play in sleep?
actively involved in processing emotions; most active during REM sleep
What role does the brain stem play in sleep?
communicates transitions b/w sleep and wake times w/hypothalamus
During sleep → produce chemicals that reduce arousal centers, send signals to relax muscles → helps keep body still and asleep
What is the reticular activating system (RAS)?
-Contains special cells that maintain alertness and wakefulness.
Receives visual, auditory, pain, pain, and tactile stimuli.
-Activity from cerebral cortex (emotions or thought processes) stimulates the RAS.
-Arousal, wakefulness, and maintenance of consciousness result from neurons in the RAS releasing catecholamines such as norepinephrine
What are the 2 processes that help regulate the sleep/wake cycle?
-Process S regulates the length and depth of sleep.
-Process C influence the internal organization of sleep and the timing and duration of sleep-wake cycles
-Both operate simultaneously to regulate sleep and wakefulness
NREM accounts for ____% of the night.
75%
Explain N1 sleep.
lightest sleep (~ mins); decreased physiological activity, decreased VS, decreased metabolism, easily aroused by noise.
Explain N2 sleep.
sound sleep, easy arousal, slowing brain & muscle activity.
Explain N3 sleep.
“Slow-wave sleep” → DEEPEST STAGE OF SLEEP → difficult to arouse, rarely moves; decreased brain and muscle activity, VS lower than waking hours.
REM sleep accounts for ___% of the night.
25%
When does REM sleep begin?
~ 90 min after sleep starts; duration increases w/each cycle (average 20min)
Why is REM sleep important?
Important for early brain development, cognition & memory.
What type of dreaming occurs in REM sleep?
Vivid, full-color dreaming.
What are some physiological manifestations that take place during REM sleep? (5)
- Autonomic response of rapidly moving eyes
- Fluctuation HR, RR, BP
- Increased gastric secretions
- Loss MSK tone
- Difficult to arouse sleeper
Explain the functions of sleep.
Sleep is regulated by CNS and is a naturally occurring altered state of consciousness
Restores biological processes
What is the sleep requirement for neonates?
16 hours
What is the sleep requirement for infants?
15 hours total with naps
What is the sleep requirement for toddlers?
12 hours total with naps
