Mechanoreceptor

Mechanoreceptors are sensory cells that convert mechanical forces in nervous excitement. They can be found in such diverse sensory organs such as the ears, the skin or the arteries. Accordingly, there is a wide variety of mechanoreceptors, which vary greatly in structure and function.

Examples of Occurrence and function

• Inner ear / hair cell: hearing
• Semicircular canals: a sense of balance
• Skin: Vibration and tactile senses
• Bloodstream reception of blood pressure
• Lateral line organ: water currents
• Muscle: Reception of muscle length

Classification

The main classification of mechanoreceptors is done according to origin. The one part of mechanoreceptors has arisen evolutionarily from epithelial and the other from the ganglion cells.

Epithelial mechanoreceptors

Epithelial mechanoreceptors are originated from cells that lay on the surface of the organism. This does not automatically mean that the receptors still lie on the surface. All epithelial mechanoreceptors are distinguished in that the conversion of an external stimulus into a physiological signal ( transduction ) in Zella slopes - the cilia - takes place. In general, performs a mechanical deformation of the cilia for opening or closing of ion channels and thus to the inhibition or excitation of the respective receptor (example: hair cell in the mammalian ear). In addition to the sensory cells of the inner ear also, among others, include most of proprioceptors in vertebrates and invertebrates to this class, as well as flow- sensitive receptors in fish and amphibians, or the vibration- sensitive sensory cells in insects. It is thought that epithelial receptor cells 2 to 3 times independently arisen in the course of evolution and represent all recent sensory cells of this type variations of such archetypes.

Ganglionic mechanoreceptors

Ganglionic mechanoreceptors are generally in the tissue and have a far aufgeästelte structure with up to 1000 terminals. The transduction takes place each in these endings. Each nerve ending can be independently excited, the single excitations are then summed in the cell body but at the latest. The combination of mechanical Charekteristika the reception of stimuli and these electrical summation properties can be a variety of different sensory abilities to (example: mechanoreceptors of the skin). The most important example of ganglionic mechanoreceptors are the sensory cells of the sense of touch in vertebrates: their cell bodies located next to the spinal cord in dorsal root ganglia, while their endings everywhere to the most remote locations can grow under the skin. Ganglionic mechanoreceptors are found but also in invertebrates, such as Tastrezeptorzellen the leeches.

Swell

• Rüdiger Wehner and Walter Gehring: Zoology. 22nd edition. Georg Thieme Verlag, Heidelberg 1995, 3-13-367423-4.
• Josef Dudel, Randolf Menzel, Robert F. Schmidt ( eds.): neuroscience. 2nd edition. Springer -Verlag, Berlin 2001, 3-540-41335-9.

The five classical senses: sight | hearing | smell | Taste | Keys Other senses: Temperature | pain | deep sensibility | sense of balance | magnetic sense Classification according to external and internal stimuli: Exterozeption | interoception

• Cell type
• Sense organ
• Nervous tissue
• Epithelium
• Receptor