Post-text assignments

Date: 2015-10-07; view: 377.

1 Describe the structure of the human eye using the picture in the text

2 Answer the questions:

1. What is the funtion of conjuctiva?

2. Is there a way to see how the pupils respond to light?

3. What is the lens?

4. What does the ciliary muscle do?

5. What is the retina?

6. What special cells does retina have?

7. What rods/cones can detect?

8. What is a visual purple? What is the function of visual purple?

9. What is the nyctalopia? What is the cause of this disorder?

3 Translate the following:

1. The outermost coat consists of the cornea and the sclera; the middle coat contains the main blood supply to the eye and consists of the choroid, the ciliary body, and the iris.

2. The cornea and the aqueous humor together make an outer lens that refracts, or bends, light and directs it toward the center of the eye.

3. When more or less light is needed to see better, the pupil becomes larger or smaller through the movement of the muscle in the iris.

4. The choroid is a layer of blood vessels and connective tissue squeezed between the sclera and the retina.

5. The lens is made of elongated cells that have no blood supply. These cells obtain nutrients from the surrounding fluids the aqueous humor in front and the vitreous body, a clear jelly, behind.

6. All of the structures needed to focus light onto the retina and to nourish it are housed in the eye, which is primarily a supporting shell for the retina.

7. There are three types of cones that receive color sensations. One type absorbs light best in wavelengths of blue-violet and another in wavelengths of green; a third is sensitive to wavelengths of yellow and red.

8. When exposed to bright light, visual purple undergoes a chemical change in which it loses its color. This causes the rods to lose their sensitivity to light, thus enabling the eye to endure glaring light.