Physiology of Sleep Flashcards
Characteristics of REM sleep
- Rapid eye movements
- Appx. 90 mins. in adults
- EEG looks like awake
- Increased arousal threshold compared to NREM
- Muscles paralyzed excepts eyes, middle ear and diaphragm
- Temp regulation suspended
- Brain temp rises
- Engorgement of clitoris and penis
- Irregular heart rate and respirations
- Most recallable dreams
- Entered through NREM
- Occurs late in sleep during early morning hours
Characteristics of NREM sleep
- N1, N2 and N3 (slow wave sleep) phases
- High amplitude, slow brain waves
- Increased arousal threshold compared to awake
- Decreased muscle activity
- Slow rolling eye movements
- Decreased heart rate, respiration and metabolism
- Occurs early in sleep
- Disorders of arousal (walking, terrors, night eating, etc.) usually during N3 slow wave sleep
Describe the interaction of the circadian (process C) and homeostatic system (process S) and their effect on wake and sleep
Your circadian rhythm (process C) operates independently of both behavior (when and how often you sleep) and light input.
In addition to the circadian rhythm, there are homeostatic processes (process S) that contribute to when you feel sleepy. This is not a specific process, but a bunch of changes that occur in you body the longer you are awake. You accumulate certain neurotransmitters (i.e. adensoine) and diminish others over the course of the day and you need to go to sleep in order to get this all back to normal and not feel tired anymore. It is pressure from both process C and process S that contribute to your sleepiness, which is ultimately reflected in fluctuations in your core body temperature. You are best able to sleep when your core body temperature is lowest and most alert when your body temperature is greatest.
Serotonin and sleep
Location: Dorsal raphe
Wake: Active
NREM: Reduced
REM: OFF
NE and sleep
Location: Locus coeruleus
Wake: Active
NREM: Reduced
REM: OFF
Histamine and sleep
Location: Tubomammillary posterior hypothalamus
Wake: Active
NREM: OFF
REM: OFF
GABA Galanine and sleep
Location: Ventral lateral pre-optic (VLPO) anterior hypothalamus
Wake: OFF
NREM: Active
REM: Reduced
Dopamine and sleep
Location: Ventral tegmental area and substantia nigra
Wake: Active
NREM:
REM: Active
Adenosine and sleep
Location: Basal forebrain
Wake: Increased
NREM: Decreased
REM: —-
Hypocretin and sleep
Location: Lateral hypothalamus
Wake: Active
NREM: OFF
REM: Some active
ACh in Pedunculopontine Tegmental (PPT) in brainstem caudal to substantia nigra
Location:
Wake: Active
NREM: OFF
REM: Very active
ACh in Pedunculopontine Tegmental (PPT) in the REM-on neurons
Location:
Wake: OFF
NREM: OFF
REM: Active
