Sheep Eye: Pre-Op May 16, 2016 We will: Go over Eye Structures Notes View Sheep Eye dissection Virtual Lab You will: Complete dissection tomorrow

THE EYE

What is a sensory organ? The purpose is how we interact with our environment. Sensory Input Integration (Brain choice) Motor Output

The Eyes are complex sensory organs designed for sight.

Human eyes are only about 1” in diameter with only about 1/6th being seen.

Eye lashes and eye brows are both designed to protect the eye.

The Conjunctiva The conjunctiva is a delicate membrane that lines the eyelids and covers part of the outer surface of the eyeball. Conjunctivitis (pink eye) is inflammation of the conjuntiva and is caused by a bacteria or virus.

Lacrimal Glands release a dilute salt solution (tears) onto the anterior surface of the eyeball. These secretions contain antibodies and lysozymes that clean and protect the eye’s surface and add moisture.

There are 6 muscles that attach to the eye There are 6 muscles that attach to the eye. These muscles allow our eyes to follow moving objects.

Cornea: Clear surface of the eye; It is the most exposed part of the eye. It can be transplanted without rejection because there is no blood supply, however is can easily repair itself. Sclera: White part of the eye

Iris: the colorful part of the eye Iris: the colorful part of the eye. The iris controls how much light passes through the pupil. Pupil: dark spot in the middle of the eye Bright light →pupil constricts Dim light → pupil dilates

Retina : contains millions of receptor cells called rods and cones. Rods see black and white. Cones see colors. They work together, so we see the world in color.

Night Blindness – Anything that interferes with rod functions Night Blindness – Anything that interferes with rod functions. The most common cause is vitamin A deficiency

VIRTUAL https://www.youtube.com/watch?v=zcumLASlKHI http://science.jburroughs.org/resources/skeleton/eye/eyedissection.html