● Depth of sleep is not constant.
● Physiological changes in GIT during sleep:
• Decrease salivary secretion.
• Gastric secretion not altered and maybe increased.
● Urine becomes darker in the morning due to increased specific gravity.
● Constricted pupil during sleep.
● REM helps in consolidation of memory.
●Sleep-wake cycle:
• Wakefulness occurs by activation of cerebral cortex and thalamus by: "Written"
° Locus coeruleus: NA.
° Raphe N. : serotonin.
° TMN: histamine.
° Ventrolateral N. of hypothalamus: orexin.
• Genesis of slow wave sleep.
• Genesis of REM sleep.