Sense of Smell

The sense of smell diminishes to some degree in aging individuals. The olfactory receptors are directly exposed to the outside environment, with their only protection of a thin layer of mucus, making them relatively susceptible to damage from such exogenous agents such as viruses, bacteria, pollutants, and airborne toxins. Moreover, since the axons of the olfactory receptor cells extend through the foramina of the cribriform plate to synapse within the olfactory bulb of the central nervous system (CNS), they are extremely vulnerable to shearing and tearing from movement of the brain relative to the cranium. Smell cells (along with taste cells) are the only sensory cells that are regularly replaced throughout a person's life span. There is an age-related decrease in the ability to identify or recognize different smells. And as an individual’s sense of smell diminishes, their ability to taste foods diminishes since smell enhances one’s ability to taste foods.