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Trigeminal Lemniscus
The trigeminal lemniscus or the trigeminothalamic tracts is a somatosensory tract containing second-order neuron fibers of the trigeminal system. It consists of the ventral and dorsal trigeminal tracts. Its second-order sensory axons convey tactile, pain, and temperature impulses from the skin of the face, the mucous membranes of the nasal and oral cavities, and the eye, as well as proprioceptive information from the facial and masticatory muscles. It terminates by synapsing with third-order neurons in the ventral posteromedial nucleus of the thalamus. This tract was historically considered a cephalic division of the medial lemniscus due to the close proximity of the two ascending tracts. Like the medial lemniscus in the dorsal column-medial lemniscus pathway (DCML), that carries mechanosensory information from part of the head and the rest of the body, the trigeminal lemniscus carries mechanosensory information from the face. However, the trigeminal lemniscus also carries p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatosensory System
The somatosensory system, or somatic sensory system is a subset of the sensory nervous system. The main functions of the somatosensory system are the perception of external stimuli, the perception of internal stimuli, and the regulation of body position and balance (proprioception). It is believed to act as a pathway between the different sensory modalities within the body. As of 2024 debate continued on the underlying mechanisms, correctness and validity of the somatosensory system model, and whether it impacts emotions in the body. The somatosensory system has been thought of as having two subdivisions; *one for the detection of mechanosensory information related to touch. Mechanosensory information includes that of light touch, vibration, pressure and tension in the skin. Much of this information belongs to the sense of touch which is a general somatic sense in contrast to the special senses of sight, smell, taste, hearing, and balance. * one for the nociception dete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second-order Neuron
Second-order may refer to: Mathematics * Second order approximation, an approximation that includes quadratic terms * Second-order arithmetic, an axiomatization allowing quantification of sets of numbers * Second-order differential equation, a differential equation in which the highest derivative is the second * Second-order logic, an extension of predicate logic * Second-order perturbation, in perturbation theory Science and technology * Second-order cybernetics, the recursive application of cybernetics to itself and the reflexive practice of cybernetics according to this critique. * Second-order fluid Second-order may refer to: Mathematics * Second order approximation, an approximation that includes quadratic terms * Second-order arithmetic, an axiomatization allowing quantification of sets of numbers * Second-order differential equation, a di ..., an extension of fluid dynamics * Second order Fresnel lens, a size of lighthouse lens * Second-order reaction, a reaction in w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigeminal System
In neuroanatomy, the trigeminal nerve ( lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for sensation in the face and motor functions such as biting and chewing; it is the most complex of the cranial nerves. Its name (''trigeminal'', ) derives from each of the two nerves (one on each side of the pons) having three major branches: the ophthalmic nerve (V), the maxillary nerve (V), and the mandibular nerve (V). The ophthalmic and maxillary nerves are purely sensory, whereas the mandibular nerve supplies motor as well as sensory (or "cutaneous") functions. Adding to the complexity of this nerve is that autonomic nerve fibers as well as special sensory fibers (taste) are contained within it. The motor division of the trigeminal nerve derives from the basal plate of the embryonic pons, and the sensory division originates in the cranial neural crest. Sensory information from the face and body is proce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral Trigeminal Tract
The ventral trigeminal tract, ventral trigeminothalamic tract, anterior trigeminal tract, or anterior trigeminothalamic tract, is a tract composed of second-order neuronal axons. These afferent fibers carry sensory information about discriminative and crude touch, conscious proprioception, pain, and temperature from the head, face, and oral cavity. The ventral trigeminal tract connects the two major components of the brainstem trigeminal complex – the principal, or main sensory nucleus and the spinal trigeminal nucleus, to the ventral posteromedial nucleus of the thalamus. The ventral trigeminal tract is also called the anterior trigeminal lemniscus. Structure The first-order neurons from the trigeminal ganglion enter the pons and synapse in the principal (chief sensory) nucleus or spinal trigeminal nucleus. Axons of the second-order neurons cross the midline and terminate in the ventral posteromedial nucleus of the contralateral thalamus (as opposed to the ventral posterola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Trigeminal Tract
The dorsal trigeminal tract (also dorsal trigeminothalamic tract, or posterior trigeminothalamic tract) are un crossed second-order sensory fibers conveying fine (discriminative) touch and pressure information from the dorsomedial division of principal sensory nucleus of trigeminal nerve to the ipsilateral ventral posteromedial nucleus of thalamus. Second-order fibers from the ventrolateral division of the principal sensory nucleus meanwhile cross-over to ascend contralaterally in the ventral trigeminal tract along with those fibers arising from the spinal trigeminal nucleus. The DTT may be likened functionally to the medial lemniscus. Trigeminal ganglion → first-order neurons → dorsomedial division of principal sensory nucleus of trigeminal nerve (in pons) (synapse) → second-order neurons → trigeminal lemniscus (in midbrain) → (ipsilateral) ventral posteromedial nucleus of the thalamus (synapse) → third-order neurons → sensory cortex of postcentral gyrus In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mucous Membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is mostly of endodermal origin and is continuous with the skin at body openings such as the eyes, eyelids, ears, inside the nose, inside the mouth, lips, the genital areas, the urethral opening and the anus. Some mucous membranes secrete mucus, a thick protective fluid. The function of the membrane is to stop pathogens and dirt from entering the body and to prevent bodily tissues from becoming dehydrated. Structure The mucosa is composed of one or more layers of epithelial cells that secrete mucus, and an underlying lamina propria of loose connective tissue. The type of cells and type of mucus secreted vary from organ to organ and each can differ along a given tract. Mucous membranes line the digestive, respiratory and rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mastication
Chewing or mastication is the process by which food is comminution, crushed and ground by the teeth. It is the first step in the process of digestion, allowing a greater surface area for digestive enzymes to break down the foods. During the mastication process, the food is positioned by the cheek and tongue between the teeth for grinding. The muscles of mastication move the jaws to bring the teeth into intermittent contact, repeatedly occlusion (dentistry), occluding and opening. As chewing continues, the food is made softer and warmer, and the enzymes in saliva begin to break down carbohydrates in the food. After chewing, the food (now called a Bolus (digestion), bolus) is swallowed. It enters the esophagus and via peristalsis continues on to the stomach, where the next step of digestion occurs. Increasing the number of chews per bite stimulates the production of digestive enzymes and peptides and has been shown to increase diet-induced thermogenesis (DIT) by activating the sympa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral Posteromedial Nucleus
The ventral posteromedial nucleus (VPM) is a nucleus within the ventral posterior nucleus of the thalamus and serves an analogous somatosensory relay role for the ascending trigeminothalamic tracts as its lateral neighbour the ventral posterolateral nucleus serves for dorsal column–medial lemniscus pathway 2nd-order neurons. The term "ventral posteromedial nucleus" was introduced by Le Gros Clark in 1930. Afferents and efferents Orofacial somatosensory The VPM receives second-order general somatic afferent fibers from the ventral trigeminal tract and the dorsal trigeminal tract which convey general somatic sensory information from the face and oral cavity (including touch, pressure, temperature, pain, and propriception). Proprioceptive synapses are situated anteriorly, ones mediating touch in the middle, and nociceptive ones posteriorly. Third-order neurons in turn project to the somatosensory cortex in the postcentral gyrus. Taste The VPM receives second-order tas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, known as the thalamocortical radiations, allowing hub (network science), hub-like exchanges of information. It has several functions, such as the relaying of sensory neuron, sensory and motor neuron, motor signals to the cerebral cortex and the regulation of consciousness, sleep, and alertness. Anatomically, the thalami are paramedian symmetrical structures (left and right), within the vertebrate brain, situated between the cerebral cortex and the midbrain. It forms during embryonic development as the main product of the diencephalon, as first recognized by the Swiss embryologist and anatomist Wilhelm His Sr. in 1893. Anatomy The thalami ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medial Lemniscus
The medial lemniscus, also known as Reil's band or Reil's ribbon (for German anatomist Johann Christian Reil), is a large ascending bundle of heavily myelinated axons that decussate in the brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ..., specifically in the medulla oblongata. The medial lemniscus is formed by the crossings of the internal arcuate fibers. The internal arcuate fibers are composed of axons of the gracile nucleus and the cuneate nucleus. The cell bodies of the nuclei lie contralaterally. The medial lemniscus is part of the somatosensory dorsal column–medial lemniscus pathway, which ascends in the spinal cord to the thalamus.Kamali A, Kramer LA, Butler IJ, Hasan KM. Diffusion tensor tractography of the somatosensory system in the human brains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Column-medial Lemniscus Pathway
Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ... * Dorsal consonant, a consonant articulated with the back of the tongue * Dorsal fin, the fin located on the back of a fish or aircraft * Dorsal transcription factor, a maternally synthesized transcription factor {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
