Senses

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Senses Objectives

Describe the sensory receptors, potential types of information sent to the brain, and common misconceptions for:

hearing (audition)
taste (gustation)
smell (olfaction)

Our senses often work together to create a richer perception of the world.

This is one of a few human biology videos we shot last year while working on our BI 101 animal biology course last summer.

Senses connect us to our external and internal environment, analogous to a car’s sensors telling it when something is too close or oil levels are low.

A classic book for understanding the significance of sensory input is Hellen Keller’s autobiography “The Story of My Life,” first published in 1903 and written while the author was still in college.

In this section you are comparing and contrasting three different senses: hearing (audition), taste, and smell (olfaction).

Common misconceptions about human senses

Ear Repair

Although some parts of the body heal quickly with healthy cells dividing to replace dead or injured cells, some cells like the receptor cells of the ears rarely divide. This means damage by a single large vibration (sound) can lead to permanent hearing loss.

Taste Map

Many older textbooks show a map of taste buds on the tongue with zones of clustered taste receptors. The tongue actually has assorted taste receptors, not specific regions of taste.

Best Sense?

When asked about their weakest sense, many people say their sense of smell. Most people can actually detect thousands of different scents, like the smell of different apple varieties, but the brain has to be taught to identify them.

Hearing (Audition)

The ear is analogous to a funnel directing vibrations to the sensory cells located in the cochlea of the inner ear.

The ears have two important sensory roles: hearing and balance.

You may have heard that when you hold a conch or other large shell to your ear, you can hear the ocean. You are actually hearing ambient noise around you amplified in the shell. It acts like a small resonating chamber.

Taste (Gustation)

This model shows the little ridges on the tongue (papillae) that have valleys lined with taste buds.

A magnification of tongue tissue clearly shows the papillae and taste buds.

An unusual stain demonstrates how varied dyes highlight different features.

Smell (Olfaction)

Ciliated receptor cells in the nasal epithelium at the roof of the nasal cavity bind to odor molecules, sending signals through an olfactory nerve to the brain.