Human Sense of Smell

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What type of cells are responsible for sensing smells in humans?

Epithelial cells
Gland cells
Muscle cells
Neurons (correct)

Where do the axons of olfactory receptor cells send impulses to?

Olfactory bulb (correct)
Thalamus
Brainstem
Cerebral cortex

What is the function of the cilia on the receptive ends of olfactory receptor cells?

To produce cyclic AMP
To extend into the layer of mucus coating the nasal cavity (correct)
To detect odorants
To transmit action potentials

What type of protein on the plasma membrane of olfactory cilia binds to odorants?

G-protein coupled receptor (B) Signup and view all the answers

What is the result of the binding of odorants to olfactory receptors?

Depolarization of the membrane (A) Signup and view all the answers

How many different odors can mammals distinguish?

Thousands (D) Signup and view all the answers

What is the percentage of the human genome that is dedicated to olfactory receptor genes?

2% (B) Signup and view all the answers

How do humans identify particular odors?

Through the expression of one OR gene in each olfactory receptor cell (C) Signup and view all the answers

What is the name of the scientist who discovered the family of olfactory receptor genes and was awarded the Nobel Prize in 2004?

Richard Axel (A) Signup and view all the answers

How many different olfactory receptor genes have been identified in mice?

1,200 (B) Signup and view all the answers

What is the purpose of the mucus coating in the nasal cavity?

To facilitate the diffusion of odorants (D) Signup and view all the answers

What is the effect of cyclic AMP on the olfactory receptor cell?

It opens channels in the plasma membrane (D) Signup and view all the answers

How do olfactory receptor cells transmit signals to the brain?

Through the generation of action potentials (D) Signup and view all the answers

What is the significance of the diversity of olfactory receptor genes?

It enables the discrimination of thousands of different odors (D) Signup and view all the answers

What is the function of the olfactory bulb in the brain?

To integrate olfactory information from the nasal cavity (D) Signup and view all the answers

What is the relationship between olfactory receptor cells and the olfactory bulb?

Each olfactory receptor cell transmits signals to a specific region of the olfactory bulb (B) Signup and view all the answers

What is the purpose of the GPCR protein on the olfactory cilia?

To bind to odorants (C) Signup and view all the answers

How do olfactory receptor cells respond to odorants?

By generating action potentials (C) Signup and view all the answers

What is the significance of the 380 OR genes in humans?

They enable the discrimination of thousands of different odors (C) Signup and view all the answers

Where are the olfactory receptor cells located in the nasal cavity?

In the upper portion of the nasal cavity (C) Signup and view all the answers

What is the result of the integration of olfactory information from different receptors?

Single sensations contributing to the perception of the environment (A) Signup and view all the answers

Why is the perception of flavor sharply reduced when the olfactory system is blocked?

Much of the complex flavor we experience is due to our sense of smell (A) Signup and view all the answers

What is the relationship between the senses of taste and smell?

They interact and influence each other (B) Signup and view all the answers

What is the significance of the integration of olfactory information in the brain?

It contributes to the perception of the environment and memory of events and emotions (C) Signup and view all the answers

What happens when the olfactory system is blocked, as occurs when you have a head cold?

The perception of flavor is sharply reduced (A) Signup and view all the answers

What is the primary way the brain processes complex mixtures of odorants?

by integrating information from different receptors (C) Signup and view all the answers

What is the primary contributor to the complex flavor experienced when eating?

the sense of smell (B) Signup and view all the answers

What is the relationship between the sense of taste and the sense of smell?

They are highly interconnected senses (B) Signup and view all the answers

What is the effect of blocking the olfactory system, as occurs when you have a head cold?

The perception of flavor is sharply reduced (D) Signup and view all the answers

What is the purpose of the integration of olfactory information in the brain?

To contribute to the perception of the environment and memory of events and emotions (A) Signup and view all the answers