الفهرس 
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Abstract
The perception of odors adds a quality to life that is difficult to express. Odors are part of our everyday life, from the pleasures of perfume to the satisfactions of toast and coffee to the warnings of shunks and fire.
Whay are primary olfactory reporter cells able to regenerate entirely when other special sensory primary neurons are not? Can olfactory tissue be transplanted in humans as demonstrated in rodents ?
Anatomy of olfactory stimulation :
Olfactory mucus :
Anatomic and Physiologic basis of olfaction :
The olfactory neuroepithelium encompasses the superior nasal septum, the cribriform plate region, and the superior turbinate with a surface area of from 2 to 10 cm2 in man. The region is bathed in a mucous blanket produced primarily by the submucosal Bowman’s glands. The vomeronasal organ of Jacobson is an accessory olfactory structure located on the inferior nasal septum; it is not known if it has sensory function in man.
The flask-shaped olfactory receptor cell is capped by a dilated plfactory knob at its lumen-facing dendritic pole. The bulb gives rise to 10 to 30 cilia of up to 100 µm in length. These nonmotile cilia bear the captor molecules for odorants, which must diffuse through the overlying mucous blanet to interact with the receptor cell. Transport of odorants through the mucus may be facilitated by odorant binding proteins. Thus, the mucus itself may play an important role by permitting or impeding odorant-receptor interaction and removing ”used” odorants.
Once the odorant and receptor molecules are associated, a complex cascade of events leads to cell membrane depolarization (generator potential) and creation of an axonal action potential. The prevailing view is that the odorant-receptor complex activates an associated GTP-sensitive G-protein, which subsequently induces adeny1 cyclase. The newly generated cyclic adenosine monophosphate facilities the opening of ion channels within the cell membrane, thus allowing the production of a generator potential. The current of this potential is carried by Na+ K+, and Ca+. Perioperative pharmacologic and metabolic alterations have the capability of perturbing this complex sequence.
Each olfactory receptor cell is responsive to several odorant molecules. A family of genes coding for olfactory receptor molecules has been discovered. There may be as many as hundreds or even thousands of individual receptor types.
Once the olfactory receptor cell axons traverse the basement membrane, they are gathered together in bundles known as fila olfactoria. These fibers are unmyelinated and Schwann cells encircle several dozen axons at a time. After passing through the foramina of the cribriform plate, the axons enter the olfactory bulb. The fila are thus held fixed at their inferior origin, but their destination, the bulb, is somewhat mobile within the cranial cavity. Injury to the fibers at this point leads to retrograde degeneration of the receptor cells.