Eyeballs are brain food. I’ll bet you didn’t know that!
Let’s find out why.
Eyeballs and brain are also two body organs that we don’t usually think about, unless close to Halloween or when ghoulish things are happening to either one or both.
This blog is the second of a series in progress about human body organs. This series follows another, which delved into each human body system.
EYEBALLS ARE ORGANS
Organs are defined as a “collection of tissues combined into a structural unit, which serves a common function.” In anatomy, an internal organ is called a viscus, and more than one are viscera. By definition, therefore, two eyeballs are organs and are viscera.
The main tissues of an organ are twofold: that which is unique for the specific organ; and the nerves, blood vessels, and connective tissues.
But, did you know that eyeballs are brain and brain food, too?
EYEBALLS ARE TISSUE
The human eye consists of three layers of eye tissue: a fibrous layer, a vascular layer, and the retina. Each layer performs a different function with regard to vision, besides forming a place where muscles may attach. The vascular layer protects portions of the eye; the fibrous layer permits and controls quantities of light to enter the eye; and the retina is the section of the eye that permits sight.
Retinas are big on sight
The retina (from Latin rēte, meaning “net”) is a light-sensitive tissue lining on the inner surface of the eye. Optics is that branch of physics involved with behavior and properties of light. Eye optics create an image of the external world on the retina, for which the cornea and lens play a part; the function is similar to that of film in a camera. Light strikes the retina and initiates a cascade of events, which trigger nerve signals sent to various visual centers of the brain. The main conduit is called the optic nerve.
Because both the retina and the optic nerve originate as outgrowths of a developing brain, thoughts of the old parlor question “Which came first, the chicken or the egg?” come to mind when considering the eyeballs and brain. The retina is considered a part of the central nervous system and is, therefore, actually brain tissue. Converted toward this organ, the eyeball, the age-old question becomes “Which came first, the brain or the retina?”
There is also a third viewpoint: “Does it really matter?”
The Fibrous Layer
The fibrous layer that is the white of an eye is called the sclera (from the Greek skleros, meaning hard). White, opaque, and hard, the sclera not only forms the shape of the eye, but also provides a surface on which eye muscles can anchor. This fibrous layer helps to protect the rest of the eye and also gives us some control over its movement.
At the front of the eye, the fibrous layer consists of the cornea, where light enters the eye. The cornea, the most exposed part of the eye, is filled with protective pain receptors. It is transparent and contains no blood vessels. Like the liver, it is able to regenerate itself when it gets damaged. Having no blood vessels, a cornea can be transplanted from person to person with little or no risk of rejection.
From One Eye Pigment, Many Colors
Eyeballs are pretty simple — simply pretty to some — constructions:
- Most eye pigment is located inside in the vascular layer of eye tissue. Pigment absorbs scattered light and helps prevent vision confusion.
- Vascular blood vessels nourish the eye.
- The ciliary body, forms a thick tissue around the lens, enabling muscles to control lens shape.
- The makeup of the Iris (on the vascular layer) determines eye color. Except for albinos, each person, regardless of eye color, only possesses brown pigment in his eyes at the back of and in the body of the iris. Hazel eyes have less pigment in the body of the iris.
- The presence of pigment located only at the back of the iris permits light to bend as it passes through the colorless part, allowing another person to only see certain light waves, resulting in different eye colors, including shades of blues and greens.
- The Pupil controls the amount of light that enters the eye. Muscles in the iris contract and dilate the pupil according to stress and the amount of light in the surrounding area. In a darkened room, when a person is scared or focused on an object far away, the pupil dilate to let in more light. A person in a bright room or focused on a nearby object, finds the pupil contracted to reduce the amount of light entering the eye.
Isn’t it really body, mind and soul?
Eyeballs are brain. Because external stimuli determine and generate the signals that are sent to the brain through them, to be interpreted in that vicinity, eyeballs are brain food, too.
That’s how it appears on the physical plane. But there is more.
More songs and poems have been written down through the ages about eyes, the colors of eyes, what they appear to communicate… and how they are “windows to the soul…” than will ever be written and popularized about the brain. Brain is, after all, merely brain.
In the beginning and in the end eyeballs are brain food and brain. Organs are not much else.
The beauty and art of Life and living… that comes from US!
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DISCLAIMER: Our information is offered here for purely educational and entertainment purposes only. We are not doctors or health professionals. We recommend that you consult with your medical or health practitioner for any health condition or illness.
© 2014 by Ronald Joseph Kule and Desiree Lotz. Reserved.