Word Origin and History for philo- Expand. before vowels phil-, word-forming element meaning loving, fond of, tending to, from Greek philo-, comb. form of philos dear (adj.), friend (n.), from philein to love, of unknown origin. Productive of a great many compounds in ancient Greek.
One way to classify neurons is by the number of extensions that extend from the neuron's cell body (soma). Bipolar neurons have two processes extending from the cell body (examples: retinal cells, olfactory epithelium cells).
The olfactory epithelium consists of 3 cell types: basal, supporting, and olfactory receptor cells. Basal cells are stem cells that give rise to the olfactory receptor cells (seen in the image below). The continuous turnover and new supply of these neurons are unique to the olfactory system.