Olfactory system

High school (ages 12+)
Human Body

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/olfactory-system

1. What is the number of functional olfactory receptor genes?
2. What is the odorant discrimination capacity?
3. How does my nose turn smells into messages for my brain?
4. Why can my nose smell so many different things even though we have fewer smell genes than some animals?

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the number of functional olfactory receptor genes?Approximately 400
2. What is the odorant discrimination capacity?Estimated to be around one trillion distinct smells
3. How does my nose turn smells into messages for my brain?When a smell touches the tiny hairs in your nose, it binds to receptors that send electrical signals. These signals travel along the olfactory nerve, go through the cribriform plate, and reach the olfactory bulb. From there, the brain reads the messages and tells you what you’re smelling.
4. Why can my nose smell so many different things even though we have fewer smell genes than some animals?Your nose uses a clever trick called combinatorial coding. Each smell is made of many parts, and the brain combines signals from many receptors to recognize over a trillion different scents.

Olfactory receptor neurons (ORNs): Bipolar neurons in the nasal epithelium that detect odorant molecules.
Glomeruli: Spherical structures in the olfactory bulb where ORN axons synapse.
Combinatorial coding: The principle that a single odor is represented by a unique combination of activated olfactory receptors.
Cribriform plate: A bony structure perforated with small holes that allows olfactory nerve fibers to pass through.