activation of receptor cells-smell

Question

can you please outline the activation of receptor cells and move up to the cerebrum(smell sense)

Answer 1

The conversion of chemical molecules (or odorants) responsible for smell into neuronal signals occurs when an odorant molecule (originating from the source of the smell) binds to a G-protein coupled receptor (G_olf) on the cilia (which are an extension of the olfactory cell/primary sensory neuron) found in the nasal cavity. Once bound, G_olf operates through a second messenger system, activating adenylate cyclase which increases intracellular cAMP, thereby opening cAMP-gated sodium/calcium channels = Na+ Ca++ influx. Ca++ influx causes the opening of Ca++ gated Cl-channels to open = Cl-efflux. Voltage-gated channels then open at the axon hillock and an action potential is fired along the axon, ending in the release of neurotransmitter (glutamate) onto the secondary sensory neurons of the olfactory bulb which then travels along the olfactory tract to interact/be processed by cerebral structures like the frontal cortex and limbic system.