a substance secreted in a glandular sac under the skin of the abdomen of the male musk deer, having a strong odor, and used in perfumery. 2. an artificial imitation of the substance. 3. a similar secretion of other animals, as the civet, muskrat, and otter. 4. the odor of musk or some similar odor.
Lens: The lens is a clear part of the eye behind the iris that helps to focus light, or an image, on the retina. Macula: The macula is the small, sensitive area of the retina that gives central. vision. It is located in the center of the retina. Optic nerve: The optic nerve is the largest sensory nerve of the eye. It. carries impulses for sight from the retina to the brain. Pupil: The pupil is the opening at the center of the iris. The iris adjusts the size. of the pupil and controls the amount of light that can enter the eye.
Rods and cones of the human eye. You can see in the drawing on the left that the back of the eye is lined with a thin layer called the retina. This is where the photoreceptors are located. If you think of the eye as a camera, the retina would be the film.The retina also contains the nerves that tell the brain what the photoreceptors are seeing.. There are two types of photoreceptors involved in sight: rods and cones.Rods work at very low levels of light.ods and Cones. show/hide words to know. 1  Cornea: is the clear outer surface of the eye the covers the iris, pupil, and the outer chamber of the eye... 2  more. 3  Epithelium: the layer of cells found lining the surface of most surfaces of the body.