Final answer:
An olfactory cell is a bipolar neuron that has receptors sensitive to specific odorants and sends signals directly to the cerebral cortex. It is involved in the perception of smell, and unlike other sensory pathways, its signals bypass the thalamus.
Step-by-step explanation:
An olfactory cell, more specifically an olfactory sensory neuron, is a bipolar neuron. These neurons have a structure that extends from their cell body. In the case of olfactory neurons, a single dendrite is buried in the olfactory epithelium, from which 5 to 20 receptor-laden, cilia emerge. These cilia trap odorant molecules, and each neuron has receptors sensitive to specific odorants. When an odorant binds to a receptor, it stimulates the olfactory neuron, leading to the perception of smell. These bipolar neurons transmit information directly to the cerebral cortex, bypassing the thalamus, which is unique among sensory pathways.
In a broader context, there are four basic types of neurons: unipolar, bipolar, multipolar, and pseudounipolar. Bipolar neurons, like those found in the olfactory system, have one axon and one dendrite extending from the soma. Multipolar neurons, in comparison, contain one axon and multiple dendrites and are the most common in the central nervous system.