the receptors for smell are located in the
Smell depends on sensory receptors that respond to airborne chemicals. In humans, these chemoreceptors are located in the olfactory epithelium â a patch of tissue about the size of a postage stamp located high in the nasal cavity. The olfactory epithelium is made up of three kinds of cells: bind to receptors on the cilia. 2  These are 7-pass transmembrane proteins. 3  Binding of the odorant activates a G protein coupled to the receptor on its cytoplasmic side. 4  This activates adenylyl cyclase, an enzyme embedded in the plasma membrane of the cilia.