Chemoreceptors: Definition, Location & Function

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  • 0:00 Definition
  • 0:50 Receptors
  • 1:50 Location
  • 3:30 How Do They Convey Messages?
  • 5:05 Lesson Summary
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Lesson Transcript
Instructor: Erika Steele

Erika has taught college Biology, Microbiology, and Environmental Science. She has a PhD in Science Education.

In this lesson, we'll discuss how the cells in our bodies use chemoreceptors to detect chemicals in the environment. We'll look at where chemoreceptors are located and how they work to help us taste, smell, and breathe. Then you can test your new knowledge with a short quiz!


Take a minute and breathe in deeply. What do you smell? Do you ever wonder how you can breathe in and smell your roommate's dirty socks? Or how you taste the salt in potato chips?

The short answer is that we have chemoreceptors in our bodies, sensory cells or organs that interact with chemicals in our blood and in what we eat and smell. These chemoreceptors then convey messages about what they've found to our brains to get a response. These responses may tell us not eat something that's rotten or to flee from the smell of smoke. Our heartbeat and respiration rates are also controlled by chemoreceptors that detect carbon dioxide, oxygen, and pH levels in the blood.


The cells in our bodies that are specifically designed for sensing have receptors on their membranes (the outside boundary of the cell). These receptors act like little fingers that grab things around them and then in turn tell your brain what they found; even if it is sensing a smell you'd rather not smell.

Receptors are designed to detect specific molecules called ligands. But they're picky and the key word here is 'specific'. Each ligand will only fit into the receptor that's specifically designed to detect it, and receptors will only convey messages about that ligand. This specificity is called a lock and key fit because only the ligand for a receptor can trigger a reaction.

Every sensation that you have starts with a receptor on a cell in your body. The sensations of smell and taste happen because of chemoreceptors located in the sensory organs of your body.


As you might guess, your sense of taste comes from taste buds on your tongue.

Your tongue has various types of taste buds that are designed to detect specific tastes, like sweet, salty. Each taste bud releases a different signal in response to being activated by a specific type of chemical taste.

Your sense of smell comes from the olfactory bulb, an organ in your nose that has chemoreceptors located on neurons in different zones that detect different types of odors. The scent of apple pie baking would be detected by neurons located in a separate zone from the neurons that detect your roommate's socks. Regardless of how pleasant, or unpleasant, an odor may be, it will be conveyed to the brain using neurotransmitters, which are brain chemicals that transmit signals from one cell to another.

Chemoreceptors are also found in our hearts and heads. If you've ever felt 'short of breath' because of exercise or nervousness, the chemoreceptors in your body have detected that oxygen levels are too low or that carbon dioxide levels are too high.

Peripheral chemoreceptors located in the heart convey messages to the central nervous system about chemical levels in the blood, including oxygen and carbon dioxide. Central chemoreceptors, located in the respiratory center at the base of your brain, monitor the levels of carbon dioxide and oxygen by detecting changes in the pH levels of the cerebral spinal fluid. If, for example, your oxygen levels are too low, your central and peripheral chemoreceptors convey a message that triggers an increase in respiration.

How Do They Convey Messages?

Now that we understand the function of chemoreceptors, let's look at how they communicate with the brain. Inside of our bodies, our cells talk to each other through cell signaling. Once enough ligands have bound with chemoreceptors, a signal is sent to the brain.

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