This is the first of two videos (1/2) presenting the anatomy and function of the human eye. This video is reliable in explaining how the structures of the human eye assist in its function. This is provided in a detail manner which enhances our understanding of the human eye.
(How the Eye Functions (1941) Part1 (2009) [Online], available from Internet on June 5: http://www.youtube.com/watch?v=UpLtf8IENJE)


This is the last of two videos (2/2) presenting the anatomy and function of the human eye. This video exemplifies a reliable understanding on the function of the human eye with direct relationship to its structures.
(How the Eye Functions (1941) Part2 (2009) [Online], available from Internet on June 5: http://www.youtube.com/watch?v=PmD7Tjb6yKo&feature=related)

eyelabeled.jpg
The above image details a structural descrption of the human eye which enables the body to detect light and form images in conjuction with the brain. This is therefore a useful source in detailing it.
(The Human Eye (2009) [Online], available from Internet on June 5: http://www.pasadenaeye.com/faq/faq15/eyelabeled.jpg)


DESCRIBE THE ANATOMY AND FUNCTION OF THE HUMAN EYE, INCLUDING THE: CONJUCTIVA, CORNEA, SCLERA, CHOROID, RETINA, IRIS, LENS, AQUEOUS AND VITREOUS HOMOR, CILIARY BODY AND OPTIC NERVE
The human eye is spherical in structure adjoined by six extrinsic muscles to bones and other muscles in the skull. These external muscles control the movement of the eyeball. The eyeball is enclosed by three layers of fibrous tissue, which are covered by a fine transparent membrane called the conjunctiva. The conjunctiva covers and protects the surface of the cornea. The sclera, on the outside (external) layer, is the ‘white of the eye’, which covers the entire eye except at the front where it is continuous with the cornea. The sclera supports and protects the eye as well as an attachment for the external eye muscles. The cornea is transparent through which light enters the eyeball. It performs much of the initial focusing of the image.

The second layer is called the choroid, is a sheet of blood vessels, which is situated between the sclera and the retina. It carries oxygen and nutrients to the eye and removes carbon dioxide and wastes. It also prevents light in the eye from scattering. The choroid also extends into the iris at the front of the eye which is a ring of muscle with a hole in the middle known as the pupil (gateway for light to pass through the lens). The iris controls the amount of light entering the eye. The inner layer is the retina, which contains a complex structure of photoreceptors, a pigment layer and nerves and bloods vessels, on the back of the eye, which allows us to see shape, movement and colour.

The lens is a transparent biconvex disc made of protein. It focuses the light onto the retina. The lens is focused with a circular, muscular ring called the ciliary body. In this way, it holds the lens in place. This arrangement divides the eye into two cavities, the anterior cavity and the posterior cavity. The anterior cavity is bounded by the cornea and the posterior cavity which occupies the volume of the eyeball. The anterior cavity produces a fluid called aqueous humor, which fills the cavity. The posterior cavity produces a jelly-like vitreous humor, which fills the eyeball and maintains the volume of the eye. The aqueous and vitreous humors help give the eyes its spherical shape and to help focus light on the retina. The retina is attached to the optic nerve that conducts the nerve impulses to the brain for processing.



Bibliography

Peter Aubusson, Eileen Kennedy, Peter Hickman (2004) Biology in Context The Spectrum of Life Second Edition, Oxford University Press, Victoria

The Human Eye (2008) [Online], available from Internet on June 8: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/V/Vision.html)