Lamellar corpuscle

Pacinian corpuscles (also Corpusculum lamellosum ) are rapidly adapting mechanoreceptors of the skin that give particularly good vibration sensations. They are named after the German anatomist Abraham 's father (1684-1751) anatomist Filippo Pacini and the Italian ( 1812-1883 ).

Occurrence

The Pacinian corpuscles are found in the subcutaneous ( under the skin ) as well as to the large tendon plates, in the pancreas, the periosteum, the vaginal wall in the retroperitoneal space and in the tissue around the bladder.

Construction

The receptor is formed by the unmyelinated end of a myelinated nerve fiber, which is surrounded by 40-60 onion-like blades made of flattened perineurial cells and a fibrous capsule. The lamellar bodies reach a size of up to 2 mm.

The unmyelinated end of the neuron represents the sensor dar. By mechanically activated ion channels a mechanical deformation of the lamellae triggers a sensor potential, which is passed elektrotonisch. This conversion of the mechanical stimulus to a change in electric potential is referred to as " transduction".

On the first constriction of the myelin sheath, the receptor potential is converted when a threshold is exceeded by the potential- dependent sodium channels opening in an action potential ( "Transformation" ).

The Pacinian corpuscle is one of the rapidly adapting receptors. It reacts to (positive and negative ) and is thus suitable as acceleration vibration detector. The highest sensitivity is located at a vibration of 300 Hz, at which a deformation of a few micrometers is sufficient to excite the receptors.

Neuronal interconnection

The action potential is passed without change within an equilateral posterior columns of the spinal cord to the brain stem and connected there to the medial lemniscus. The railway crosses the further course to the opposite side and reaches the thalamic nuclei. After re- switching the information then reaches the sensitive areas of the cerebral cortex.

Krause 's corpuscles

The smaller version of the Pacinian corpuscle - is also called Krause 's corpuscles.