Information about Merkel Cell
Merkel cells are large oval cells found in the skin of vertebrates. They are associated with the sense of touch, and are responsible for the highly malignant skin tumor known as Merkel cell carcinoma.
History
They were named after the 19th century anatomist Friedrich Sigmund Merkel who was the first to fully describe them in 1872.Location
Merkel cells are found in the skin and some parts of the mucosa (stratum germinativum) of all vertebrates. In mammalian skin they are clear cells found in the stratum basale of the epidermis, and measure 10 – 15 µm across. Most often they are associated with sensory nerve endings, when they are known as Merkel nerve endings.Function
The exact function of Merkel cells is unclear. F.S. Merkel referred to them as Tastzellen or "touch cells", although their function has been disputed ever since. Merkel cells are sometimes considered APUD cells because they contain dense core granules, and thus may have a neuroendocrine function.Developmental origin
Merkel cells are derived from cells of the neural crest.See also
External links
Nervous system, receptors: somatosensory system | |
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| Medial lemniscus | |
| Spinothalamic tract | |
Merkel cell cancer, also called Merkel cell carcinoma, trabecular cancer, Apudoma of skin, or Small cell neuroepithelial tumor of the skin, is a rare and highly aggressive cancer where malignant cancer cells develop on or just beneath the skin and in
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Friedrich Sigmund Merkel (1845 – 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.
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Stratum germinativum (also stratum basale or basal cell layer) is the layer of keratinocytes that lies at the base of the epidermis immediately above the dermis.
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Epidermis may refer to:
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- Epidermis (botany), in plants, the outermost layer of cells covering the leaves and young parts of a plant
- Epidermis (skin), in vertebrates, the outermost layer of the skin
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Merkel nerve endings are mechanoreceptors found in the skin and mucosa of vertebrates that provide touch information to the brain. Each ending consists of a Merkel cell in close apposition with an enlarged nerve terminal.
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Neuroendocrine [IPA nʊəroʊˈɛndəkrɪn] cells are a specialized group of nerve cells (neurons) that produce hormones. These hormones may be amines, neuropeptides, or specialized amino acids.
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The neural crest, a transient component of the ectoderm, is located in between the neural tube and the epidermis (or the free margins of the neural folds) of an embryo during neural tube formation.
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Merkel nerve endings are mechanoreceptors found in the skin and mucosa of vertebrates that provide touch information to the brain. Each ending consists of a Merkel cell in close apposition with an enlarged nerve terminal.
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Merkel cell cancer, also called Merkel cell carcinoma, trabecular cancer, Apudoma of skin, or Small cell neuroepithelial tumor of the skin, is a rare and highly aggressive cancer where malignant cancer cells develop on or just beneath the skin and in
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and also stops input from the senses, and initiates actions. Prominent parts of a nervous system include neurons and nerves, which are used in coordination.
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In a sensory system, a sensory receptor is a structure that recognizes a stimulus in the internal or external environment of an organism. In response to stimuli the sensory receptor initiates sensory transduction by creating graded potentials or action potentials in the same cell
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Somatic sensation consists of the various sensory receptors that trigger the experiences labelled as touch or pressure, temperature (warm or cold), pain (including itch and tickle), and the sensations of muscle movement and joint position including posture, movement, and facial
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The medial lemniscus, also known as Reil's band or Reil's ribbon, is a pathway in the brainstem that carries sensory information from the gracile and cuneate nuclei to the thalamus.
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A mechanoreceptor is a sensory receptor that responds to mechanical pressure or distortion. There are four main types in the glabrous skin of humans: Pacinian corpuscles, Meissner's corpuscles, Merkel's discs, and Ruffini corpuscles.
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Pacinian corpuscles are one of the four major types of mechanoreceptor, responsible for sensitivity to deep pressure touch and high frequency vibration.
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Location
These corpuscles are found in mesenteries, especially the pancreas, and are often found near joints...... Click the link for more information.
Meissner's corpuscles (or tactile corpuscles) are a type of mechanoreceptor, responsible for sensitivity to light touch.
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Location
They are distributed throughout the skin, but concentrated in areas especially sensitive to light touch, such as the fingertips, palms,..... Click the link for more information.
Merkel nerve endings are mechanoreceptors found in the skin and mucosa of vertebrates that provide touch information to the brain. Each ending consists of a Merkel cell in close apposition with an enlarged nerve terminal.
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The Ruffini ending or Ruffini corpuscle is a class of slowly adapting mechanoreceptor thought to exist only in the glabrous dermis and subcutaneous tissue of humans. It is named after Angelo Ruffini.
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A free nerve ending (FNE) is an unspecialized, afferent nerve ending, meaning it brings information from the body's periphery to the brain. Free nerve endings are unencapsulated and have no complex sensory structures, unlike those found in Meissner's or Pacinian corpuscles.
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Location Cochlea
Function Amplify sound waves and transduce auditory information to the Brain Stem
Morphology Unique (see text)
Presynaptic connections None
Postsynaptic connections
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Function Amplify sound waves and transduce auditory information to the Brain Stem
Morphology Unique (see text)
Presynaptic connections None
Postsynaptic connections
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Baroreceptors (or baroceptors) in the human body detect the pressure of blood flowing through them, and can send messages to the central nervous system to increase or decrease total peripheral resistance and cardiac output.
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Proprioception (PRO-pree-o-SEP-shun (IPA pronunciation: [ˈpɹopɹiːoˌsɛpʃən]); from Latin proprius
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The Golgi organ (also called Golgi tendon organ, neurotendinous organ or neurotendinous spindle), is a proprioceptive sensory receptor organ that is located at the insertion of skeletal muscle fibres into the tendons of skeletal muscle.
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Muscle structure is innervated by both sensory and motor neuron axons. The Muscle Spindle's functions are to send proprioceptive information about the muscle to the central nervous system, and to respond to muscle stretching.
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Intrafusal fibers are muscle fibers that comprise the muscle spindle. These fibers are walled off from the rest of the muscle by a collagen sheath. This sheath has a spindle or "fusiform" shape, hence the name "intrafusal.
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Nuclear chain fiber is a specialized sensory organ contained within a muscle. Nuclear chain fibers are intrafusal fibers which, along with nuclear bag fibers, make up the muscle spindle responsible for the detection of changes in muscle length.
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1 to 3 nuclear bag fibres lie in the centre of each intrafusal muscle fibre of a muscle spindle. Each has a large number of nuclei concentrated in bags and they cause excitation of both the primary and secondary nerve fibres.
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See also
- nuclear chain fiber.
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The spinothalamic tract is a sensory pathway originating in the spinal cord that transmits information about pain, temperature, itch and crude touch to the thalamus. The pathway decussates at the level of the spinal cord, rather than in the brainstem like the posterior
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Pain is a sensation transmitted from sensory nerves through the spinal cord and to the sensory area of the cerebrum, where the sensation is perceived. It is defined by the International Association for the Study of Pain (IASP) as “an unpleasant sensory and emotional
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