Chapter 12: Smell and Taste
Both smell and taste are considered chemosensations: ways we sense chemicals. The “chemicals” we’re sensing are molecules that float through the air (smell) or come from the things we put in our mouths (taste). Taste and smell are closely related—they combine to produce our perception of flavor, and they rely on receptors (neurons) that actually come into contact with the environment outside our body. The rest of our sensory neurons are protected from the world by a layer of skin or some other tissue. Because they’re protected, there is no process for regeneration, and once a neuron in your eyeball or inner ear dies, it doesn’t get replaced. But olfactory receptors and taste neurons both take a lot of abuse and new cells are born throughout our lives to replace the ones that die.
Learning Objectives
- Describe the location and function of the olfactory epithelium, the olfactory bulb, and the olfactory cortex.
- Describe an olfactory neuron and explain what a cilium is.
- Describe approximately how many types of olfactory receptors there are and how they are distributed
- Describe the paradoxical relationship between scent and memory.
- Differentiate between detection and recognition thresholds
- Describe the vomeronasal gland and its function
- Argue for and against the presence of pheromone communication in humans.
- Define anosmia and give two examples of why it happens.
- Describe why anosmia can be dangerous.
- Differentiate between a taste bud and a papilla.
- Name the different kinds of papillae and their function
- Describe the 6 different dimensions of taste and what they rely on
- Describe what it means to be a non-taster, a taster, or a supertaster.
- Describe the taste and olfactory pathways from receptors to the brain
- Explain how the sense of smell contributes to our perception of flavor.
- Describe why infants have appetitive responses to sweetness and aversive responses to bitterness.
- Describe how taste and smell are affected by aging.
- Describe how orbitofrontal cortex impacts appetite.
- Describe how blood sugar inhibits responses in the nucleus of the solitary tract.
- Describe why texture affects appetite.
This chapter was created by Shawna Ratanpal, Rowan Sexton, Kori Skrypek, Brock Sorensen, Samantha Strubing, Barbora Tomancova, Savannah Vasek, Alex Wallace, Jacob Weckwerth, Maria Xiong, Peter Yong, and Grace Zellner.
