What are olfactory nerve cells

Olfactory cells

Olfactory cells, Olfactory cells,olfactory sensory cells, olfactory receptor cells, E.olfactory cells, specialized, bipolar, primary nerve cells of the olfactory epithelium, which react very sensitively and selectively, but relatively unspecifically, to odorant molecules (fragrances) and convert the chemical signal into an electrical signal (chemo-electrical signal transduction; see additional info 1). The basal process of the sensory cells (axon) projects to the olfactory bulb, the first switching station for olfactory nerve impulses in the brain. Olfactory cells that express the same type of olfactory receptor (olfactory receptor) project onto a small number of glomeruli olfactorii that are bilaterally symmetrically distributed between the olfactory bulb halves. - The apical extension (dendrite) of the olfactory cells pulls between supporting cells to the surface, where it forms a button-like thickening (Knob) ends. Depending on how the knobs are equipped with chemosensory cilia or microvilli, a distinction is made between ciliary or microvillary olfactory cells, some of which occur either as a single type or together in the olfactory epithelium. Olfactory cells have a lifespan of around 35 days and are replaced by new cells from the basal cell population after they have degenerated. They are the only nerve cells that continuously arise from postnatal neurogenesis. - In insects the olfactory sense cells are mainly located in the antennae, where their branched or unbranched chemosensory dendrites are embedded in porous, hollow, cuticular structures (olfactory sensilla) and surrounded by sensilla lymph. Insect olfactory cells can be divided into 2 main types: Generaliststhat react to a wide range of different fragrances, and Specialiststhat react highly specifically, e.g. only to pheromone components (pheromones) (see additional info 2).

Olfactory cells

1 The number of olfactory cells is very different in the individual animals according to the efficiency of the olfactory sense. So are in 5 cm2 large olfactory epithelium in humans has only about 10 million receptors, whereas in the 85 cm2 large olfactory epithelium of the dog contain approx. 230 million sensory cells.

Olfactory cells

2 The silk spider man (Bombyx mori) has specialized sensors that react selectively but very sensitively to the female pheromone bombykol: it is assumed that a single molecule can trigger a nerve impulse in the sensory cell; the activation of only approx. 200 sensory cells induces a characteristic behavior of the Bombyx males.