Nervous System                       

Contents

• Olfactory area - Nerve signals representing smells are routed to two regions of the brain: the medial (inner) olfactory area and the lateral (side) olfactory area in the amygdala. Figure 18 shows the pathway of the odorants in the air, which initiates impulses moving along the nerve pathway to the brain. Since the nerve pathway is in part of the brain's limbic system, which also deals with memories and emotions, smell can evoke strong emotion from past experience about a certain odor. Smell is the sense in which habituation occurs most quickly. Habituation is the process in which a sense becomes accustomed to what it detects so that it is no longer perceived. Most odors can hardly be perceived just 30 seconds after they are first detected.

  Figure 18 Pathways [view large image]

  The sense of taste and the sense of smell supplement each other, creating a combined effect when interpreted by the cerebral cortex. For example, some of the molecules may move from the nose down into the mouth region and stimulate the taste buds there. Therefore, part of what we refer to as smell actually may be taste.

  
  
  Taste (see location of the various components in Figure 09):