A receptor is a molecule found on the surface of a cell usually and responsible for receiving chemical signals originating externally from the cell.These signals bind to the receptor and initiate any activity of cell like division, movement etc.
There are different types of receptors in the human body like thermoreceptors for temperature, chemoreceptors for chemicals , photoreceptors for light etc. If these receptors do not work properly, body will not be able to generate stimulus and action on time which may lead to serious harm to the body.