How the Body Works : Exploring the Eye

Exploring the Eye

As we explore the eye, we see that the eyes are organs of sight, situated in orbits, the sockets in the skull, the walls of which protect them from injury. The eyelashes, eyelids, muscles and lacrimal glands also protect these vital and delicate organs. The eye is divided into two segments by the lens and ciliary body. The front segment contains the fluid aqueous humor, and is in turn divided, by the iris, into anterior and posterior chambers, which are connected through the pupil's aperture in the iris. The back segment, called the vitreous body, contains a jellylike substance, known as the vitreous humor, and is lined by the light sensitive retina. The iris is an adjustable diaphragm with an aperture, the pupil, in its center. It acts like a valve, controlling the amount of light entering the eye. The lens is a transparent, biconvex body, enclosed in a thin, elastic, transparent capsule. It is supported by ligaments attached to the ciliary body, which can change its shape. The ciliary muscle, composed of smooth muscle under involuntary control, alters the shape of the lens. The suspensory ligaments connect the ciliary muscle to the lens, and hold the lens in place. The hyaloid canal is the remains of a channel that carried an artery during the development of the eye in the fetus. The cornea, aqueous humor, lens and vitreous humor are all transparent, thus allowing the unobstructed passage of light from the exterior, through the eyeball, to the retina. The cornea is the most important structure for refracting light, although the lens provides the fine control needed to converge the incoming rays into the retina. The most striking external feature of the eye is the iris, the pigment-filled membrane that gives the eye its color, varying from light blue to dark brown.

Category:

Howto & Style

Tags:

• Exploring
• the
• Eye

[archilles1195]

@strek0655 You see, when we sneeze, we automatically close our eyes. The pressure from sneezing is so strong that it can cause serious discomfort when sneezing with eyes opened. It's an automatic response, a stimuli, we don't choose not to open, the brain tells the eyes to close it. Closing eyes when sneezing sound so trivia, because we can also close the eyes by ourselves. Can mutation works in such a way that it creates AUTOMATIC stimulus in the brain every time we sneeze and got selected?

[archilles1195]

I'd love it if, every time I burb, the brain automatically triggers my vocal cord to say "excuse me". Sometimes I forgot and that's gross.

[archilles1195]

@strek0655 I also have one question for you. I read one of the reasons for eye evolution is to avoid predators. Having said that, for predators which has no known predators, they have to evolve eyes as well otherwise they'll starve to death, right? That sounds planned.

[archilles1195]

@strek0655 And there's no information in DNA to code for these, and it cannot exist to accommodate eyes all of sudden, otherwise it indicates intelligence. So, tears, blinking, eye lids must serve different functions before it's adopted by the eyes for proper function. It's very valid to argue what's good is tear duct without tears, or tears without eyelid, or blinking to lubricate and the eyes, automatically. So, what were the functions of those before it got integrated by the eyes?

[archilles1195]

@strek0655 Don't confine your argument with the eyeball. Let's talk about vision as a whole, and there are 40 components in human eyes. All evolutionists like to answer is comparing to simpler organism, and you are talking about mole. For example, blinking, tear ducts and tears cannot come into existence by chance, those are vital for the operation of the eyes, otherwise it got damaged, right. Cont'd:

[strek0655]

@archilles1195 Can the eye work without a lens? Yes, but not very well. Can it work without the ciliary muscle? Sure, but accommodation would be impossible . Can it work without the trochlear, abducent and oculomotor nerves, yes but you would have to turn your head to every point. These are all evolutionary additions to the primary function which is photosensitive cells. You do know that there are animals which have a poor eyesight because their adaptation doesnt require them to see (mole)

[archilles1195]

@strek0655 You are wrong. Islamic countries also respect Adam and Eve. No, they don't claim "unfinished" eyes, they just said that eyes cannot work if anyone of its part is missing, which is completely valid. What you have is a dogma.

[archilles1195]

@strek0655 No, creation is awesome.

[tomp2008]

The inside of my eyeball is not humorous, nor virtuous, thank you.

[JohnBlack666id]

@0FFICALXFACT0R The position is behind the eye.