retina

n. the light-sensitive inner surface of the eye. A layer of neurons lines the inner surface of the back of the eye and provides the sensory signals required for vision. The retina contains the photoreceptors—that is, the retinal rods and retinal cones—as well as additional neurons that process the signals of the photoreceptors and convey an output signal to the brain by way of the optic nerve. This inner layer of the retina is sometimes called the neural retina, to distinguish it from the retinal pigment epithelium, which abuts the tips of the photoreceptors. See also amacrine cell; retinal bipolar cell; retinal horizontal cell; retinal ganglion cell.

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Psychology term of the day

November 18th 2024

health activities questionnaire

any questionnaire designed to measure an individual’s current repertoire of health-related behaviors. In health care there is an increased emphasis on prevention, and many inventories exist to measure an individual’s compliance with physical activity, dietary control, preventive inoculations, and screening for potential health problems, such as mammography and prostate or colon cancer testing.