When You're the One Canceling a Flight. In defense of Spirit, most airlines operate on razor thin margins and refund dollars do add up. Even airlines that allow refunds-generally only under very special circumstances-may make you jump through hoops and even pay a fee.
Medical Definition of receptor. 1  1: a cell or group of cells that receives stimuli : sense organ. 2  2: a chemical group or molecule (as a protein) on the cell surface or in the cell interior that has an affinity for a specific chemical group, molecule, or virus.
Hormone receptors are found either exposed on the surface of the cell or within the cell, depending on the type of hormone. In very basic terms, binding of hormone to receptor triggers a cascade of reactions within the cell that affects function.Additional details about receptor structure and function are provided in the section on hormone mechanism of action.ormone receptors are found either exposed on the surface of the cell or within the cell, depending on the type of hormone. In very basic terms, binding of hormone to receptor triggers a cascade of reactions within the cell that affects function.