receptorcell

A receptor cell is a specialized cell that detects a specific external or internal stimulus and converts it into a signal that can be interpreted by the nervous system or by other cells. Sensory receptor cells are typically located within sensory organs or in peripheral ganglia and may signal via neurotransmitter release to afferent neurons or, in some cases, directly through action potentials.

Common types include photoreceptors in the retina, which respond to light; olfactory receptor neurons in the nasal epithelium, which detect odor molecules; taste receptor cells in taste buds, which sense tastants; and mechanosensory hair cells in the inner ear and touch receptors in the skin. Receptor cells often express specific receptor proteins on their membranes, such as ligand-gated ion channels or G protein–coupled receptors, which bind their stimulus and trigger transduction cascades.

Transduction converts the stimulus into a receptor potential, which may lead to the release of neurotransmitter onto a nearby neuron or to the initiation of an intrinsic electrical signal. In photoreceptors, transduction modulates cyclic nucleotide levels and membrane conductance; in olfactory and taste receptor cells, binding events typically trigger transmitter release to sensory neurons.

Receptor cells are a focus of study in physiology and neuroscience and contribute to medical diagnostics and biosensing. Dysfunction or loss of receptor cells can lead to sensory deficits, such as vision or smell loss, while some receptor systems retain regenerative capacity.