Sleep to these four stages of aSleep to these four stages of a


Sleep is
a substantial part of our lives and linked with reduced of stimuli. During
sleep, our brains and our bodies have the chance to recover after complicated
activities. Sleep phenotype were categorized depending on:

Specific position 2- reduced reaction 3- reversible 4-

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DR.Ysbrand explained that they use EEG in the brain to
measure the electrical activity in the brain because EEG signals associated
with being a sleep are different from those funding during a wake. Additionally,
the diverse stages of a sleep can be measured via EEG and EOG which is used to
measure eye movement during a sleep to specify the stage of the sleep.


During the first stage of sleep, we can see Theta
waves. Theta waves are greater in amplitude and slower in activity than alpha
waves which mainly express during the rist in wakefulness. In stage two, we can
recognize sleep spindles and and K complex. During a sleep a sleeper moves from
Theta waves of stage 2 to delta waves in stage 3 and 4. Delta waves are highest
amplitude and the slowest in the brain waves. In addition to these four stages
of a sleep, scientists recognize REM stage. During REM stage, the brain illustrates
waves similar to the waves during waking. This stage linked with dreaming. In
fact, sleeper moves from stage 1 to stage 2 then stage 3 and 4 then back to
stage 1 in circle. This circle repeated many times during a normal night. We
called this case (sleep in circle).


It is proved that sleep is regulated via different
redundant structures in the hypothalamus, brain stem, and basal forebrain.
However, Ventrolateral preoptic nucleus (VLPO) or (VLPN) of the hypothalamus is
involved between sleep and wakefulness by suppressing the activity of brain
stem during a sleep. Additionally, Orexin which mainly produce by neurons in
the hypothalamus triggers wakefulness. While, GABA is a main inhibitory
transmitter of the CNS triggers a sleep.


Dr. Ysbrand explained that, the optimal sleep duration
is (6,5) hour per day and the risk of mortality is increased when the sleep
duration is increased. Therefore, women are greater in risk of dying due to
their prolonged sleep. Additionally, the patterns of our sleep change due to
aging process.


The speaker specified two kinds of sleep disorders. 1- Too
little sleep: such as (Insomnia, restless leg, periodic limb movement syndrome,
narcolepsy, apnea, parasomnias)   2- Too much sleep: such as (Excessive day time
sleepiness (EBS)), narcolepsy, Hypersomnia. In fact, the prevalence of insomnia
is 31%. Therefore, we should do more research on sleep disorders to improve
public health in our society.

The lecturer advised students not to use medicines as a
sleep therapy. Drinking alcohol leads to bad sleep because sleeper cannot sleep
deeply. Drinking coffee should be stopped at the midday to get good sleep
during night. Additionally, he introduced some therapies which used to treat
sleep disorders such as:

1-sleep restriction (sleeping less 7 hour per day).

2-Cognitive behavioral therapy.                                                                

3- Bright
light therapy. 

4-Sleep hygiene.


6-Body temperature manipulations.


In conclusion, sleep is essential
for optimal health and can affect our lives. We sleep to recover and recur or
bodies and our brain after a long work day. Through good sleep, we can continue
our activity vigorously.