Kinesiology 3347A/B Lecture Notes - Lecture 10: Environmental Noise, Motor Neuron Disease, Encephalopathy
21 Apr 2016
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Document Summary
Sensation is triggered by a stimulus activating a sensory receptor: impulses travel via sensory (afferent) nerve pathways to the brain. Perception is a multistage process in the central nervous system: includes: selection, processing, organization, and integration of information received from the senses. Visual sensation: infants have functionally useful vision. During first month: develop 5% of eventual adult acuity. Cannot see objects beyond 20 inches: by 6 months of age, vision is adequate for locomotion through the environment, acuity is approximately 20/30 by age 5 and 20/20 by age 10. Reading block letters where size decrease by level and become closer together measures visual acuity. Results are expressed on the snellen scale of visual acuity: 20/20 vision requires no correction. Asymmetric steepening of the cornea causes light to be focused unevenly. To individuals with uncorrected astigmatism, images may look blurry or shadowed. Cornea causes the light to create unequal focal points.
