How are olfactory neurons classified structurally?

Structurally, olfactory neurons are classified into two types:

1. Primary Olfactory Neurons: Also known as olfactory receptor neurons or sensory neurons, primary olfactory neurons are bipolar neurons located in the olfactory epithelium. They are responsible for detecting and transmitting odorant signals to the brain. Each primary olfactory neuron expresses a single type of odorant receptor protein, allowing for a diverse array of odor detection.

2. Secondary Olfactory Neurons: Also called mitral cells or tufted cells, secondary olfactory neurons are located in the olfactory bulb, which is the first relay center of the olfactory pathway in the brain. These neurons receive signals from primary olfactory neurons and relay the processed olfactory information to higher brain areas, such as the amygdala and cortex, for odor perception and discrimination.