What is a receptor?
The word receptor is derived from the Latin word recipere, meaning “to receive” or “to receive”. To put it very simply, a receptor could be described as 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. The image of a key (messenger) and lock (receptor) is often chosen as a metaphor – only when both fit together does a reaction trigger.
Receptor: Sensory cells in the body
Each receptor only reacts to a single specific stimulus – like the first link in a chain of our senses, the receptor functions as a kind of biological sensor. If the stimulus is strong enough, it is diverted into an action potential and thus reaches the central nervous system.
A distinction is made between primary sensory cells, which generate action potentials themselves (e.g. the touch receptors on the skin), and secondary sensory cells, which do not independently form action potentials (e.g. the taste receptors).
membrane receptor and nuclear receptor
The so-called membrane receptors are found on the surface of biomembranes . In addition to transmitting signals, the receptors also fulfill the function of transporting substances into a cell. However, viruses can also get into a cell in this way.
Independent of this, special proteins function as nuclear receptors. A nuclear receptor is the landing site for certain hormones – the receptor also picks up the signal here and converts it, which affects the production of certain proteins.
Receptors are highly specialized
Since each receptor is only designed for a single stimulus, a highly specialized system is required to allow us to perceive a sensory impression. For example, in order to be able to feel touch, the skin must be equipped with receptors for cold, heat, pressure and pain.
Each temperature receptor constantly relays information about body temperature to the central nervous system. As a rule, it can no longer use temperatures below 10 degrees or above 45 degrees; this is where the pain receptors come into play.