In today's post, which happens to be my first here on steemit community, I'm going to write on a metaphorical Subject** " THE EYE: THE WINDOW TO THE SOUL "** . Before I go on explaining this figurative expression , I will like you to know a little about your eyes, you may think you already know about your eyes, but I bet you friend, you don't know as much as you think.
You have seen that notice above, fasten your seat belt, because you are about to lunch into a new world of knowledge with a supersonic speed. Are you ready? Okay!
Firstly, let's see how a layman may define the eyes. He may define the eyes as two white structures situated on the either sides of the nose. Simple and short! But there's more to the eye than what has been said above. Though this definition tells the location of the eyes relative to the ear, mouth and the nose, respectively, but does not come close in telling us what the eye really is.
Now, let's see a proper definition of the eyes. According to Dictionary.com, an online company who's domain name was registered on May 14, 1995. It was founded by Brian Kariger and Daniel Fierro, It defined the eye as "the organ of sight, in vertebrates typically one of a pair of spherical bodies contained in an orbit of the skull and in humans appearing externally as a dense, white, curved membrane,or sclera, surrounding a circular, colored portion, or iris, that is covered by a clear, curved membrane, or cornea, and in the center of which is an opening, or pupil, through which light passes to the retina."
It sounds more like a biology class right? I know a lot of folks Reading this post are not in love with biology at all, especially those big-big terminologies and jargons used. But do not worry, you will enjoy this ride.
Looking at the above comprehensive definition by dictionary.com , you will see that alot of terms were implicated. Such terms as vertebrate, spherical bodies, orbit, skull, sclera, iris, cornea, pupil and retina. For you to really say you know about the eyes, you must be able to tell what these terms I listed above stand for.
VERTEBRATES :
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What are vertebrates? Simply put, vertebrates are a group of animals which posses back bones. If you direct your hand to your back now, you will feel a long bone running from the back of your neck to your buttocks. It's called spinal cord. So you are a vertebrate. other examples include birds, fishes etc.
SPHERICAL BODIES :
The eyes are seen as spherical bodies. Now, what are spherical bodies? Also, simply put, they are bodies that are almost circular, but not exactly circular. Like the shape of an egg. We can say that your eyes are like the shape of eggs. Are you following?
ORBIT :
What is an orbit? It is the cavity (hole) which contains your two eyes. Your eyes are inside the orbits of the skull. What you see as the eyes, is just a part of the whole eye.
SKULL:
Again, what is a skull? I know alot of you already have an idea about what the skull is. Notwithstanding, the skull is a bone framework (like a box) enclosing the brain and the eyes.
SCLERA :
I bet, some of you are hearing this word for the first time! Winks! Now, what is sclera? It is the white portion you see in the eye, that is, the white part surrounding an almost round black structure. You are now becoming a "guru" of the eyes.
IRIS:
This is a flat, coloured, ring-shaped membrane behind the cornea of the eye, with an adjustable circular opening (pupil) in the centre. Don't worry about this big grammars. It is simply that blue ( in some people it's black , brown etc.) part of your eyes. It is actually at the back of the cornea.
CORNEA :
Cornea is the transparent layer forming the front of the eye. It is in front of that black, blue or brown portion of your eyes.
PUPIL :
It is the dark circular opening in the centre of the iris( by now you know what the iris is) of the eye, which varies in size to regulate the amount of light reaching the retina. Now, if you look closely into your eyes in the mirror, you will see a small very black circle in the centre of the iris ( bigger black, blue or brown portion). The size changes depending on the amount of light. In the presence of light, it constricts (becomes small). While in the absence of light, it dilates ( becomes large in size).
RETINA :
Finally, what is retina? It is a layer at the back of the eyeball that contains cells sensitive to light, which trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed. Do not be bored by this definition of the retina. I will explain. Now, remember I said earlier that the eye is spherical in shape, like an egg right? The whole of that egg, let's take it as the eyeball. If you break an egg, the inside layer ( inside wall ) is the retina for the eyes. The retina contains some cells called photoreceptor, very many of them, which are sensitive to light. When you look at anything in the presence of light, the light on that thing reflects into your eyes and goes into the retina at the back . It is from this retina, information goes to your brain. The brain will now interpret what reflected the light.
Because of the scope of this post, I will not go into much detail about the eyes, I will specially write a post about the eyes. However, by now I believe you have the basic understanding about the eyes, right?