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Eyes
| Term | Definition |
|---|---|
| Cornea | Transparent part of the eye. Continuous with the sclera. |
| Sclera | White part of the eye. Outermost layer of the eye made up of tough connective tissue. |
| Choroid | Middle layer of the eye. Made up of melanocytes that absorb light. |
| Tapetum | Reflective layer found in some animals. Allows for night vision. |
| Retina | Innermost layer. Made up of photoreceptors. (Rods and Cones) |
| Aqueous Humor | Located at the front of the eye. Provides shape and nourishment to the front of the eye. |
| Iris | Coloured part of the eye. Made up of smooth muscles and connective tissue. Controls the amount of light entering the eye. |
| Lens | Transparent tissue that is stretched and compressed to focus light on the retina. Held in place by cilliary muscles. |
| Vitreous Humor | Located inside the eyeball. Provides nutrients and shape to the inside of the eyeball. |
| Rods | Located in the retina. Used for black and white and night vision. |
| Cones | Located in the retina. Used for coloured vision. Three types: red, blue, and green |
| Night blindness | When the rods do not function properly. |
| Colour blindness | X-linked recessive. Cones don't work properly or at all. |
| Glaucoma | An increased amount of aqueous humor or fluid in the eye creates pressure that will lead to blindness. |
| Myopia | Nearsightedness. The eyeball is too long. Need concave lens to fix. |
| Hypermetropia | Farsightedness. The eyeball is too short. Need convex lens to fix. |
| Cataract | The lens becomes cloudy or opaque |
| Astigmatism | Uneven curvature of the cornea or lens. |