Written Essay Questions
a) We are able to experience different types of sensations because our nervous system encodes messages. German physiologist Johannes Muller in his doctrine of specific nerve energies described a kind of code which is anatomical. In his doctrine, Muller explains that different sensory modalities exist because signals received by the sense organs stimulate different nerve pathways that lead to different areas of the brain. For example, when the ear receives signals, these signals cause impulses to travel along the auditory nerve to the auditory cortex. And signals from the eye cause impulses to travel along the optic nerve to the visual cortex. Because of these anatomical differences, light and sound produce different sensations.
b) The code in the nervous system that helps explain why a pinprick and kiss feel different is known as functional. These codes rely on the fact that sensory receptors and neurons fire or are inhibited from firing, only in the presence of specific kinds of stimuli. Functional encoding may occur all along a sensory route, starting in the sense organs and ending in the brain.
2. The lens of an eye operates differently from a camera, that just like a camera, the eye registers spots of light and dark, but neurons in the visual system build up a picture of the world by detecting meaningful features. The eye doesn’t passively record the external world, like a camera, ganglion cells and neurons in the thalamus of the brain respond to simple features in the environment, such as spots of light and dark. The existence of a specialized face module in the brain, explains why a person with brain damage may continue to recognize faces, after losing the ability to recognize other objects.
3. These units which were named after Alexander Graham Bell were called decibels (dB). Each decibel is 1/10 of a bel. Using decibels, they can be used to determine sound intensity, intensity of a wave’s