Meissner Corpuscles: Structure, Function & Diseases

Meissner’s corpuscles are RA mechanoreceptors that sense pressure changes and belong to the differential receptors. Meissner corpuscles exclusively report pressure changes and adapt to constant pressure stimuli. Misperceptions of the receptors often have their origin in the central nervous system.

What is the Meissner corpuscle?

Receptors are the first site of human perception. These sensory cells detect specific stimuli and also convert the excitation into a language that the central nervous system can understand and process. For the active haptic and passive tactile sense of touch, in addition to the thermoreceptors for temperatures and the nociceptors for pain, the mechanoreceptors for mechanically acting forces such as pressure, vibration and touch play a particularly important role. Mechanoreceptors in humans correspond to either PC, SA, or RA receptors. The Meissner tactile corpuscles, or Meissner corpuscles for short, are rapidly adapting RA receptors in the groin skin. The sensors were named after their discoverer, Georg Meissner. Meissner’s corpuscles are pressure receptors that fall into the class of so-called differential receptors and thus measure changes in stimuli. Meissner’s corpuscles are capable of adapting to a constant pressure stimulus and, instead of transmitting information on permanently constant pressure, only transmit information on pressure changes to the central nervous system. The sensors also belong to the group of lamellar corpuscles.

Anatomy and structure

Meissner corpuscles are located primarily in the fingertip and lips. Meissner’s corpuscles are not present in hairy areas of the skin and thus the field skin. The receptors are located in the stratum papillare of the dermis within all areas of the field skin. The sensors are between 100 and 150 µm long and have the shape of a cone. Externally, the receptor organs are surrounded by a capsule of connective tissue known as the perineural sheath, which fixes the corpuscles in the surrounding tissue. Within this connective tissue capsule lie nerve fibers that are largely surrounded by insulating myelin. The myelin improves the conductivity of the nerve tissue and protects the nerves from loss of potential. The Meissner corpuscles are sheathed by five to ten myelin sheaths in the form of Schwann cells, which lie on top of each other in a stack. The terminals of the nerve fibers are not myelinated within the perineural sheath and are therefore open to environmental pressure stimuli. Upon exposure to pressure, the open nerve terminals generate action potentials. Each Meissner corpuscle is approximately 40 to 70 μm wide and is attached to up to seven dendritic axons that wind helically around the cell.

Function and tasks

Meissner corpuscles are rapidly adapting RA and differential receptors. The action potential frequency generated by the sensors is proportional to the speed of a pressure stimulus change. The receptive field of a Meissner corpuscle has a large area and a high resolving power, which leads to a better differentiation of closely spaced pressure stimuli. Meissner corpuscles generate an action potential only when the stimulus strength changes. For example, they respond when the skin is depressed. However, as soon as they have adapted to the new low position of the skin, they no longer emit signals. Their adaptation to a constant pressure stimulus occurs at a rate of 50 to 500 ms. Meissner corpuscles play a key role not only for the human sense of touch precisely because of their adaptability to pressure and are, for example, the reason why humans no longer perceive clothing on the skin as a noticeable touch stimulus after a short time. Together with the mechanoreceptive Merkel cells for measuring pressure intensity, the Ruffini corpuscles for stretch stimuli and the Vater-Pacini lamellar corpuscles for vibration, the Meissner corpuscles form a system of particularly specialized sensory cells that is capable of registering and systematizing all touch stimuli on the skin. Action potentials of a certain resting frequency are generated at the nerve fiber of the Meissner’s corpuscles when pressure changes. Initially, the frequency of the potential rises steeply, but immediately after the rise, it falls back to the resting value, although the triggering stimulus is still acting.When the stimulus stops, the frequency of the Meissner corpuscles falls below the resting value and returns to it. The response behavior of Meissner’s corpuscles is called dynamic or phasic response. In addition to Meissner bodies, hair follicles are also differential receptors.

Diseases

In most cases, dysfunction of Meissner bodies is not due to damage in the sensory cells themselves. Most apparently receptor-associated diseases are due to damage to the stimulus-transmitting neural pathways. Such damage can be the result of central nervous tissue inflammation, for example, as is present in conditions such as the autoimmune disease multiple sclerosis. In addition, strokes, spinal cord infarctions, polyneuropathies of the peripheral nervous system, or tumors of the central nervous system can cause misperceptions of the Meissner corpuscles. Actual receptor diseases should be distinguished from nerve-associated diseases, which are often preceded by a system-impairing intoxication. In other cases, actual receptor diseases are caused by a receptor mutation. If such a mutation is present, then unlike the nerve-associated diseases, symptoms occur immediately after birth. The nerve-associated diseases with apparent receptor association also usually cause general sensory disturbances and thus do not manifest clinically exclusively as misperception of the Meissner corpuscles. In receptor-associated diseases due to mutations, defective receptors result from the mutation. Thus, sensory cells are no longer capable of ligand binding, signal transduction, or signal transduction, for example. Other mutations do not build Meissner bodies in sufficient quantities or do not produce them in sufficient quantities in the first place. Receptor-associated diseases also include the so-called ion channel diseases, which cause the Meissner corpuscle to generate insufficient action potentials.