Describe the stages of a normal sleep cycle.
Stage 1: very light sleep, the person is drowsy and relaxed. The eyes roll from side to side, heart and respiration drop slightly, the person can easily be awakened. This stage lasts for a few minutes.
Stage 2: a sound sleep, but the person can still be awakened easily. Relaxation progresses and the eyes are still. The body processes continue to slow, heart, respirations and temp drop slightly. This stage lasts 10-20 minutes.
Stage 3: the person is difficult to arouse. Skeletal muscles are very relaxed and the person is undisturbed by sensory stimuli. Vital signs decrease but are stable, the person barely moves. Lasts 15-30 mins.
Stage 4: the deepest sleep stage, the person is very difficult to arouse. The heart and respiration rates are 20%-30% below waking rates. The person is extremely relaxed and rarely moves. Last 15-30 mins.
REM sleep begins 90 mins or so after falling asleep. the person has active vivid dreams and is difficult to arouse or wake spontaneously. There is REM, and fluctuation of heart, respirations and BP rates. Gastric secretions and brain metabolism increase.
Pre-sleep sleepiness- NREM1- NREM2- NREM3- NREM4- REM sleep- NREM2- NREM3-----
NREM2 is the door stage because it is the entrance/exit for REM sleep