The word receptor derives from the Latin word recipere, meaning "to receive" or "to receive". Simply stated, one could call a receptor the docking point of a cell, typically the cell surface. When messenger substances, proteins or hormones reach the receptor, they trigger a specific signal in the cell. As a metaphor often the image of key (messenger) and lock (receptor) is selected - only when both fit together, it comes to trigger reaction.
Receptor: sensory cells in the body
Each receptor only responds to a single specific stimulus - like the first link in a chain of our senses, the receptor acts as a kind of biological sensor. If the stimulus is strong enough, it is redirected to an action potential and thus reaches the central nervous system.
A distinction is made between primary sensory cells, which themselves generate action potentials (for example, the skin's contact receptors), and secondary sensory cells, which do not independently develop action potentials (such as the taste receptors).
Membrane receptor and nuclear receptor
On the surface of biomembranes one finds the so-called membrane receptors. In addition to the transmission of signals, the receptors additionally fulfill the function of transporting substances into a cell. In this way, but also viruses can get into a cell.
Regardless, special proteins act as nuclear receptors. A nuclear receptor is the dock for certain hormones - the receptor also picks up and transforms the signal, which affects the production of certain proteins.
Receptors are highly specialized
Since each receptor is designed for just one stimulus, a highly specialized system is needed to make us experience the senses. For example, to feel a touch, the skin must be equipped with receptors for cold, heat, pressure and pain.
Each temperature receptor continuously provides information about body temperature to the central nervous system. He can not use temperatures below 10 degrees or over 45 degrees usually no longer; Here are the pain receptors.