Question

chapter 15 end of chapter review question 9
1 part | -- of 1 point

how are the olfactory receptors activated?

the olfactory tracts transduce signals to the hypothalamus.

odorants dissolve in the mucus and bind to receptors.

mitral cells relay signals to the olfactory bulbs.

olfactory cilia move mucus over the receptors.

Explanation:

To determine how olfactory receptors are activated, we analyze each option:

• The first option is incorrect because olfactory tracts send signals to the brain (not hypothalamus) after receptors are activated.
• The second option is correct: Odorants (smell - causing molecules) dissolve in the nasal mucus and then bind to olfactory receptors, triggering their activation.
• The third option is incorrect as mitral cells are involved in relaying signals from the olfactory bulbs (not to them) after receptor activation.
• The fourth option is incorrect; olfactory cilia have receptors, and mucus helps odorants reach them, but cilia don't move mucus over receptors to activate them.

Answer:

B. Odorants dissolve in the mucus and bind to receptors.