Sensory Receptor CellsMechanoreceptorsMonotremataNeuroepithelial BodiesPulmonary Stretch ReceptorsHair Cells, AuditoryChemoreceptor CellsNeurons, AfferentPhysical StimulationOlfactory Receptor NeuronsReflexPhotoreceptor Cells, InvertebrateVagus NerveMuscle SpindlesAfferent PathwaysNociceptorsCochleaCapsaicinAdaptation, PhysiologicalAction PotentialsChemotaxisSignal TransductionModels, BiologicalImmunohistochemistry