Binocular vision can be found in animals with two eyes. When these two eyes overlap in their field of view, depth perception is produced, this is known as stereoscopic vision. These terms coincide by allowing the specimen to perceive distance between it and an object. For example, when playing dodgeball, judging how far away your opponent is, tells you how hard you need to throw the ball to tag him out.
When viewing an object from afar, the sympathetic nervous system is activated, causing the eyes to dilate. This happens due to the ciliary and sphincter muscles relaxing, the lens becoming stretched flat, and the pupillary dilation muscle contracting. However, when the parasympathetic nervous system becomes activated, the opposite chain of events occur. The ciliary and sphincter muscles contract, the lens and pupillary dilation muscle remains relaxed; the eyes then constrict.
The blind spot is located in the back of the eye where blood vessels and nerves exit the eye joining the optic nerve; in this region no rods or cones or receptors are found. A person with a vision of 6/7, is said to have less acute vision than
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The smaller the receptive fields the more dense are the tactile receptors. The smallest distance in which one point was felt occurred in the fingertips at 5 mm; the largest distance occurred on the back at 27 mm. The results observed make sense, because fingertips are one of the most sensitive areas in the body, so therefore needs to have more receptors, whereas, the back is a larger area and tactile receptors are more spread out, therefore sensitivity declines. This difference occurs, because humans use their hands more often. This is beneficial and can help aid in protection. For example, when picking up an object if it is thorny, or extremely hot your sensory neurons sends signals to your brain telling you to let release it in order not to harm