Question

When Dissecting a cow eye

Choose two structures that you observed in your dissection. Describe each structure that you choose and summarize its function.

Answer 1

This activity should be done practically, in order to guide you , I will explain all structures along with their identification and function.
COW'S EYE DISSECTION

1.Fat tissue around eyes which function as to protect eyes from surrounding bony tissue.

2. Red muscular tissue - Cows have four muscles around eyes and their function to move their eyes up, down, left and right.

3. Cornea -Cloudy covering seen over iris and pupil. It is made of layers of interlocking fibers that strengthens it and protect the eye from harmful particles. Function is to focus most of the light that enters the eye. (The cornea may be cloudy after death, but would have been translucent when alive).

4. Aqueous humor - As we make an incision in cornea, a clear liquid will leak out from the incision. That is aqueous humor. Function is to help the cornea retain its shape and nourishes the front part of the eye.

5.Iris and Pupil - After cutting out entire cornea, underneath the cornea it is the iris. It is suspended between the cornea and the lens. A cow's iris is brown . It is an involuntary muscle that will change the size of the hole in the center of it, called pupil ,which is oval in shape and controls how much light enters the eye.In dim light, the pupil opens wide to let light in and in bright light, the pupil close down to block light out.

6. Lens - A clear marble like structure with many layers can be felt . The lens is flexible so that it can change shape, focusing on objects that are close up and objects that are far away.

7.Vitreous humor - A jelly like substance, which is mixture of protein and water. It’s clear so light can pass through it. It also helps the eyeball main-tain its shape.

8. Retina - Inside back half of the eyeball, a thin fleahy film along with blood vessels called retina. Function is to detect light using cells present in them.  The cells of the retina react to the light that falls on them and send messages to the brain.The spot where the retina is attached to the back of the eye is called the blind spot, where there are no light-sensitive cells present.

9.Optic nerve - Round proteubence that can be felted at posterior part of eye.These are the bundle of nerves that carries messages from the eye to the brain. The brain uses information from the retina to make a image.

10. Tapetum - Shiny, blue-green stuff under the retina. It is covering of back eye.
Function is to reflects light from the back of the eye.