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Merkel Disk
Merkel nerve endings (also Merkel's disks, or Merkel tactile endings) are mechanoreceptors situated in the basal epidermis as well as around the apical ends or some hair follicles. They are slowly adapting. They have small receptive fields measuring some millimeters in diameter. Most are associated with fast-conducting large myelinated axons. A single afferent nerve fibre branches to innervate up to 90 such endings. Merkel nerve endings respond to light touch. They respond to sustained pressure, and are sensitive to edges of objects. Their exact functions remain controversial. The Merkel nerve endings consist of a nerve ending associated with a flattened epithelial cell (Merkel cell); both the nerve ending and Merkel cell are independently mechanosensitive. The Merkel cell expresses the PIEZO2 mechanosensitive ion channels; mechanical activation of the channel causes depolarisation of the Merkel cell and consequent release of serotonin into a synapse with the associated nerve endi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elsevier
Elsevier ( ) is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as ''The Lancet'', ''Cell (journal), Cell'', the ScienceDirect collection of electronic journals, ''Trends (journals), Trends'', the ''Current Opinion (Elsevier), Current Opinion'' series, the online citation database Scopus, the SciVal tool for measuring research performance, the ClinicalKey search engine for clinicians, and the ClinicalPath evidence-based cancer care service. Elsevier's products and services include digital tools for Data management platform, data management, instruction, research analytics, and assessment. Elsevier is part of the RELX Group, known until 2015 as Reed Elsevier, a publicly traded company. According to RELX reports, in 2022 Elsevier published more than 600,000 articles annually in over 2,800 journals. As of 2018, its archives contained over 17 million documents and 40,000 Ebook, e-books, with over one b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprioception
Proprioception ( ) is the sense of self-movement, force, and body position. Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of proprioceptors, which detect distinct kinesthetic parameters, such as joint position, movement, and load. Although all mobile animals possess proprioceptors, the structure of the sensory organs can vary across species. Proprioceptive signals are transmitted to the central nervous system, where they are integrated with information from other Sensory nervous system, sensory systems, such as Visual perception, the visual system and the vestibular system, to create an overall representation of body position, movement, and acceleration. In many animals, sensory feedback from proprioceptors is essential for stabilizing body posture and coordinating body movement. System overview In vertebrates, limb movement and velocity (muscle length and the rate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friedrich Sigmund Merkel
Friedrich Sigmund Merkel (5 April 1845 – 28 May 1919) was a leading German anatomist and histopathologist of the late 19th century. In 1875, he provided the first full description of ''Tastzellen'' (touch cells), which occur in the skin of all vertebrates. They were subsequently given the eponym " Merkel cells" in 1878 by Robert Bonnet (1851–1921). Merkel was a native of Nürnberg. In 1869 he earned his medical doctorate from the University of Erlangen, becoming habilitated in the field of anatomy during the following year. He was a professor at the Universities of Rostock (from 1872), Königsberg (from 1883) and Göttingen (from 1885). At Göttingen, he worked under Jacob Henle and married Henle's daughter Anne. He published a multivolume textbook on human anatomy and originated the color scheme used by most anatomy texts today: red for arteries, blue for veins, and yellow for nerves. He introduced xylene as a clearing agent in histology, and it is still used today T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Braille
Braille ( , ) is a Tactile alphabet, tactile writing system used by blindness, blind or visually impaired people. It can be read either on embossed paper or by using refreshable braille displays that connect to computers and smartphone devices. Braille can be written using a slate and stylus, a braille writer, an electronic braille notetaker or with the use of a computer connected to a braille embosser. For blind readers, braille is an independent writing system, rather than a code of printed orthography. Braille is named after its creator, Louis Braille, a Frenchman who lost his sight as a result of a childhood accident. In 1824, at the age of fifteen, he developed the braille code based on the French alphabet as an improvement on night writing. He published his system, which subsequently included musical notation, in 1829. The second revision, published in 1837, was the first Binary numeral system, binary form of writing developed in the modern era. Braille characters are f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tactile Discrimination
Tactile discrimination is the ability to differentiate information through the sense of touch. The somatosensory system is the nervous system pathway that is responsible for this essential survival ability used in adaptation. There are various types of tactile discrimination. One of the most well known and most researched is two-point discrimination, the ability to differentiate between two different tactile stimuli which are relatively close together.two-point discrimination. (n.d.) ''McGraw-Hill Concise Dictionary of Modern Medicine''. (2002). Retrieved March 16, 2018 from https://medical-dictionary.thefreedictionary.com/two-point+discrimination Other types of discrimination like graphesthesia and spatial discrimination also exist but are not as extensively researched.Blumenfeld, H. (2010). 'Neuroanatomy Through Clinical Cases' (2nd Edition ed.). Sunderland, Massachusetts: Sinauer Associates Inc. http://www.neuroexam.com/neuroexam/content41.html. Tactile discrimination is something ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Receptive Field
The receptive field, or sensory space, is a delimited medium where some physiological stimuli can evoke a sensory neuronal response in specific organisms. Complexity of the receptive field ranges from the unidimensional chemical structure of odorants to the multidimensional spacetime of human visual field, through the bidimensional skin surface, being a receptive field for touch perception. Receptive fields can positively or negatively alter the membrane potential with or without affecting the rate of action potentials. A sensory space can be dependent of an animal's location. For a particular sound wave traveling in an appropriate transmission medium, by means of sound localization, an auditory space would amount to a reference system that continuously shifts as the animal moves (taking into consideration the space inside the ears as well). Conversely, receptive fields can be largely independent of the animal's location, as in the case of place cells. A sensory space can also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscillation
Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum and alternating current. Oscillations can be used in physics to approximate complex interactions, such as those between atoms. Oscillations occur not only in mechanical systems but also in dynamic systems in virtually every area of science: for example the beating of the human heart (for circulation), business cycles in economics, predator–prey population cycles in ecology, geothermal geysers in geology, vibration of strings in guitar and other string instruments, periodic firing of nerve cells in the brain, and the periodic swelling of Cepheid variable stars in astronomy. The term ''vibration'' is precisely used to describe a mechanical oscillation. Oscillation, especially rapid oscillation, may be an undesirable phenomenon in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Principles Of Neural Science
''Principles of Neural Science'' is a neuroscience textbook edited by Columbia University professors Eric R. Kandel, James H. Schwartz, and Thomas M. Jessell. First published in 1981 by McGraw-Hill, the original edition was 468 pages, and has now grown to 1646 pages on the sixth edition. The second edition was published in 1985, third in 1991, fourth in 2000. The fifth was published on October 26, 2012 and included Steven A. Siegelbaum and A.J. Hudspeth as editors. The sixth and latest edition was published on March 8, 2021. Authors Editors * Kandel was one of the recipients of the 2000 Nobel Prize in Physiology or Medicine. He is currently a professor of biochemistry, molecular biophysics, physiology, cellular biophysics, and psychiatry at Columbia University. He is a senior investigator at the Howard Hughes Medical Institute and a recipient of the National Medal of Science. * Schwartz was a professor of physiology, cellular biophysics, neurology, and psychiatry at Columbia U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eric R
The given name Eric, Erich, Erikk, Erik, Erick, Eirik, or Eiríkur is derived from the Old Norse name ''Eiríkr'' (or ''Eríkr'' in Old East Norse due to monophthongization). The first element, ''ei-'' may be derived from the older Proto-Norse ''* aina(z)'', meaning "one, alone, unique", ''as in the form'' ''Æ∆inrikr'' explicitly, but it could also be from ''* aiwa(z)'' "everlasting, eternity", as in the Gothic form ''Euric''. The second element ''- ríkr'' stems either from Proto-Germanic ''* ríks'' "king, ruler" (cf. Gothic ''reiks'') or the therefrom derived ''* ríkijaz'' "kingly, powerful, rich, prince"; from the common Proto-Indo-European root * h₃rḗǵs. The name is thus usually taken to mean "sole ruler, autocrat" or "eternal ruler, ever powerful". ''Eric'' used in the sense of a proper noun meaning "one ruler" may be the origin of '' Eriksgata'', and if so it would have meant "one ruler's journey". The tour was the medieval Swedish king's journey, when newly e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meissner's Corpuscles
Tactile corpuscles or Meissner's corpuscles are a type of mechanoreceptor discovered by anatomist Georg Meissner (1829–1905) and Rudolf Wagner. This corpuscle is a type of nerve ending in the skin that is responsible for sensitivity to pressure. In particular, they have their highest sensitivity (lowest threshold) when sensing vibrations between 10 and 50 hertz. They are rapidly adaptive receptors. They are most concentrated in thick hairless skin, especially at the finger pads. Structure Tactile corpuscles are encapsulated myelinated nerve endings, surrounded by Schwann cells. The encapsulation consists of flattened supportive cells arranged as horizontal lamellae surrounded by a connective tissue capsule. The corpuscle is 30–140 μm in length and 40–60 μm in diameter. A single nerve fiber meanders between the lamellae and throughout the corpuscle. Location They are distributed on various areas of the skin, but concentrated in areas especially sensitive to lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacinian Corpuscles
The Pacinian corpuscle (also lamellar corpuscle, or Vater–Pacini corpuscle) is a low-threshold mechanoreceptor responsive to vibration or pressure, found in the skin and other internal organs. In the skin it is one of the four main types of cutaneous receptors. The corpuscles are present in skin notably on both surfaces of the hands and feet, arms, and neck. Pacinian corpuscles are also found on periosteum, bone periosteum, joint capsules, the pancreas and other internal organs, the breast, genitals, and Lymph node, lymph nodes. Pacinian corpuscles are rapidly adapting mechanoreceptors. As phasic receptors they respond quickly but briefly to a stimulus with the response diminishing even when the stimulus is maintained. They primarily respond to vibration, and deep pressure. They are especially sensitive to high-frequency vibrations. Groups of corpuscles sense pressure changes (such as on grasping or releasing an object). They are additionally crucially involved in proprioception ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rapidly Adapting Receptor
A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are located on sensory neurons that convert mechanical pressure into electrical signals that, in animals, are sent to the central nervous system. Vertebrate mechanoreceptors Cutaneous mechanoreceptors Cutaneous mechanoreceptors respond to mechanical stimuli that result from physical interaction, including pressure and vibration. They are located in the skin, like other cutaneous receptors. They are all innervated by Aβ fibers, except the mechanorecepting free nerve endings, which are innervated by Aδ fibers. Cutaneous mechanoreceptors can be categorized by what kind of sensation they perceive, by the rate of adaptation, and by morphology. Furthermore, each has a different receptive field. By sensation * The Slowly Adapting type 1 (SA1) mechanoreceptor, with the Merkel corpuscle end-organ (also known as Merkel discs) detect sustained p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
