DESIGN of Smell Process

 See, the smell of my son is as the smell of a field which the LORD hath blessed... Genesis 27:27

 

"The human nose is designed to detect a trillion smells......Sensory neurons in the nose 

--detect odor molecules 

--and relay signals to the olfactory bulb, a structure in the forebrain where initial odor processing occurs. 

--The olfactory bulb primarily transmits information to the piriform cortex, the main structure of the olfactory cortex, for more comprehensive processing.

As a person inhales through the nose, the air with the ordorant molecules goes across millions of olfactory neurons in the nasal cavity. 

These specially-designed neurons have surface receptors called GPCRs (G-Protein Coupled Receptors). 

The odorant molecule—called a ligand—specifically binds with a G-protein receptor and immediately causes a biochemical cascade of reactions (intracellular adenyl cyclase components) within the neuron.
When a volatile molecule [ligand] is recognized by a [G-protein] receptor, it is activated 

---and generates a signal that is transmitted to the olfactory bulb in the brain, 

---a signal that is then translated into an odor.....olfactory neurons are not to be considered as sensors simply passing from a resting state to a stimulated state, but that their identity is in permanent [change], not only according to the expressed receptor but also according to past experiences. 

This discovery adds another level to the complexity and flexibility of the olfactory system...."

ICR