Why we close our Eyes While sleeping
Hints/Cues
Why close our eyes while sleeping? What impulse, quasi
to an involuntary act and causing the eye to close its lid can be so
overwhelming to prevent? Or just maybe the eye sleeps too and
shut its lid without your consent………..Ah! Very funny. As funny as it sounds, it
is not empty of inwits but bewits with both hints and cues that the eye will
close its lid because that is its own way of resting.
The
daily rhythm of reduced consciousness during which an animal rest is sleep. A natural
and daily phenomena that might occur more than once within 24 hours and serving
as time out for all functioning part of the body.
With a reduced consciousness while asleep,
what really happens on the inside at this moment cannot be decrypted to
wholesomeness but there is some propriety quite apparent and common to all that
breathes. That is, it is the Brain’s rest moment from its every day chores of
responding to countless impulse from different organs, muscles, tissues
etcetera. More like the dictating, grand and aced organ in human or animals
taking a break for the day ere all others becomes free of duty and relaxes.
Note: Sleep
means the Brain is asleep ergo, the Brain’s consciousness at this revered trice
is reduced or cut down and when this happens, the Brain does not respond to external
stimuli. However, the Brain {most part of it}, particularly the Amygdala, stays
active at sleep but its awareness of reality is somewhat benumb. Yes during REM
[Rapid Eye Movement] sleep, the Brain is active, just its perception of the
real world torpified.
Occipital
Lobe [A portion of the Brain preempting the visual world] “Eyelids closed”
The
Occipital Lobe interprets action potentials [Light impulse] as apt images on
the Retina
[a part of the central nervous system
that converts light energy to action potential that travels out the optic nerve
into the Brain and gets feedback of apt images from the brain] as it responds
swiftly to the impulse it receives from the Optic nerve which interacts with the
Rods and Cones in the Retina [light sensitive areas in the
eye]. While sleeping [a state of reduced consciousness], just as the Brain in
whole is asleep, the portion of the Brain that controls vision or sight [the
Occipital Lobe] is asleep too. At this moment of recess, the occipital lobe’s
consciousness of the real world/surrounding environment is reduced or cut down
ergo, our visual world turns gloomy as if clouded with darkness.
In a state of reduce consciousness
[sleep], the Occipital Lobe is non responsive to external stimuli of any sort
therefore no light energy, detected by light sensitive neurons in the Retina
[Photoreceptive Rods and Cones] and undergoes photo-transduction in the Retina
changing the light energy to action potential, is interpreted or responded to
and that is if light energy is even converted to action potential by the Retina
during the sleep moment.
Note: The Retina is a part of the central nervous system and this means that
while the Brain [a part of the central nervous system] is asleep, the Retina also a part of the central
nervous system [CNS] could be non-responsive too therefore and may not be
transducing light energy while asleep.
Just before sleep takes a human or an
animal abruptly, the eyes responding to the Brain portion that preempts vision
[Occipital lobe] and acting with the physiology/internal environment of the
human or animal, shuts its lids and so the eyelids are close during sleep.
Basically, because the Occipital goes to sleep being a portion of the Brain
that is asleep while a human or an animal sleeps, the eyelids has to be close
because then no image can be interpreted on the Retina since the part of
the Brain that Preempts vision is asleep.
Both eyes might be open during sleep
for some eccentric cases, however this does not undermine the unresponsiveness
of the Occipital lobe and the reality of sleep itself which is a state of reduce
consciousness during which an organism rest. Even with both eyes open while
asleep, like a friend of mine “a bright young man” who sleeps with both eyes
open [sorry can’t disclose his name or identity], such person is still visually
clueless at this delicate moment of sleep, for the reason that his/her visual
world is been cut down since the portion of the Brain that preempts vision is
asleep and becomes unresponsive to external stimuli.
Although light may go in through the
Iris, with both eyes open, and light
energy might have been detected by light sensitive neuron in the Retina
and could have undergone photo-transduction in the Retina to become action
potential, the individual still will have no visual clue or perception of its
external environment because the Occipital lobe is non responsive while asleep
ergo such individual with both eyes open while sleeping is visually clueless as
a blind person.
Even
with both eyes open in a sleep, there is still no visual clue or perception of
the surrounding. Still another reason why the eye must be closed while sleeping
I think.
Unihemispheric
Sleep
A special and survival mechanism in
animals like Whales, Dolphins, Seals, Ducks and some other birds allowing such
animal to sleep while half of its Brain is still responsive for the reason that
half of the Brain sleeps as the animal sleeps therefore, the animal while
sleeping will still have visual clues of its environment although no fully.
Unihemispheric sleep is a survival feature
particular to some animals that allows them to sleep with half of their Brain.
During a Unihemispheric sleep, half of the brain is asleep and so, one eye is
open and the other is closed. This kind of sleep is so different from a ‘sleep’
where both eyes are open but the Brain is asleep for this reason, in Unihemispheric
sleep, half of the Brain is still responsive to external stimuli ergo, the
portion of the Brain that preempts vision [the Occipital lobe], half of it, is
still responsive too and will interpret any action potential it receives as apt
image on the Retina, provided that light energy enters the eye through the
pupil “a perforated spot in the Iris” and is being detected by the
photoreceptive Rods and Cones and transduced by the retina to action potential
which travels out to the Occipital lobe via the Optic nerve.
In
Unihemispheric sleep, the animal in question can still see but with one eye
because half of the Brain is responsive still [conscious of the real world] while
the other half is asleep. This survival feature [Unihemispheric sleep] helps
the animal to have a clue of it environment and aware of predators so they
don’t get eaten by them [their natural predators] while asleep.
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