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Internal Medullary Lamina
Medullary laminae of thalamus are layers of myelinated fibres that appear on cross sections of the thalamus. They also are commonly referred to as laminae medullares thalami or medullary layers of thalamus. The specific layers are: *Lamina medullaris lateralis (external medullary lamina) — separates ventral and lateral thalamus from the subthalamus and thalamic reticular nucleus *Lamina medullaris medialis (internal medullary lamina) — positioned between the dorsomedial and ventral nuclei of thalamus, encloses the intralaminar nuclei (centromedian nucleus In the anatomy of the brain, the centromedian nucleus, also known as the centrum medianum, (CM or Cm-Pf) is a nucleus in the posterior group of the intralaminar thalamic nuclei (ITN) in the thalamus. (This must not be confused with the central me ..., paracentral, and central lateral) External links * References Thalamus {{neuroanatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myelin
Myelin Sheath ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be likened to an electrical wire (the axon) with insulating material (myelin) around it. However, unlike the plastic covering on an electrical wire, myelin does not form a single long sheath over the entire length of the axon. Myelin ensheaths part of an axon known as an internodal segment, in multiple myelin layers of a tightly regulated internodal length. The ensheathed segments are separated at regular short unmyelinated intervals, called nodes of Ranvier. Each node of Ranvier is around one micrometre long. Nodes of Ranvier enable a much faster rate of conduction known as saltatory conduction where the action potential recharges at each node to jump over to the next node, and so on till it reaches the axon terminal. At the terminal the ... [...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] |
Ventral
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Terminolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Anatomical Terms
Anatomical terminology is a specialized system of terms used by anatomists, zoologists, and health professionals, such as doctors, surgeons, and pharmacists, to describe the structures and functions of the body. This terminology incorporates a range of unique terms, prefixes, and suffixes derived primarily from Ancient Greek and Latin. While these terms can be challenging for those unfamiliar with them, they provide a level of precision that reduces ambiguity and minimizes the risk of errors. Because anatomical terminology is not commonly used in everyday language, its meanings are less likely to evolve or be misinterpreted. For example, everyday language can lead to confusion in descriptions: the phrase "a scar above the wrist" could refer to a location several inches away from the hand, possibly on the forearm, or it could be at the base of the hand, either on the palm or dorsal (back) side. By using precise anatomical terms, such as "proximal," "distal," "palmar," or "do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subthalamus
The subthalamus or ventral thalamus is a part of the diencephalon. Its most prominent structure is the subthalamic nucleus. The subthalamus connects to the globus pallidus, a subcortical nucleus of the basal ganglia. Structure The subthalamus is located ventral to the thalamus, medial to the internal capsule and lateral to the hypothalamus. It is a region formed by several grey matter nuclei and their associated white matter structures, namely: *The subthalamic nucleus, whose neurons contain glutamate and have excitatory effects over neurons of globus pallidus and substantia nigra * Zona incerta, located between fields of Forel H1 and H2. It is continuous with the thalamic reticular nucleus and receives input from the precentral cortex. * Subthalamic fasciculus, formed by fibers that connect the globus pallidus with the subthalamic nucleus * Fields of Forel * Ansa lenticularis During development the subthalamus is continuous with the hypothalamus, but is separated by whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalamic Reticular Nucleus
The thalamic reticular nucleus is part of the ventral thalamus that forms a capsule around the thalamus laterally. However, recent evidence from mice and fish question this statement and define it as a dorsal thalamic structure. It is separated from the thalamus by the external medullary lamina. Reticular nucleus cells are all GABAergic, and have discoid dendritic arbors in the plane of the nucleus. Thalamic Reticular Nucleus is variously abbreviated TRN, RTN, NRT, and RT. The TRN is found in all mammals. Input and output The thalamic reticular nucleus receives input from the cerebral cortex and dorsal thalamic nuclei. Most input comes from collaterals of fibers passing through the thalamic reticular nucleus. The outputs from the primary thalamic reticular nucleus project to dorsal thalamic nuclei, but never to the cerebral cortex. This is the only thalamic nucleus that does not project to the cerebral cortex. Instead it modulates the information from other nuclei in the thala ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centromedian Nucleus
In the anatomy of the brain, the centromedian nucleus, also known as the centrum medianum, (CM or Cm-Pf) is a nucleus in the posterior group of the intralaminar thalamic nuclei (ITN) in the thalamus. (This must not be confused with the central medial nucleus, which is in the anterior group of the ITN.) There are two centromedian nuclei arranged bilaterally. In humans, each centromedian nucleus contains about 2200 neurons per cubic millimetre and has a volume of about 310 cubic millimetres with 664,000 neurons in total. It measures less than 10 millimetres in every dimension. It belongs to the caudal intralaminar group of thalamic nuclei and is situated within the medial thalamus. It is bordered superiorly by the mediodorsal nucleus, medially by the parafascicular nucleus, and posteriorly by the pulvinar. Input and output It sends nerve fibres to the subthalamic nucleus and putamen. It receives nerve fibres from the cerebral cortex, vestibular nuclei, globus pallidus, superior col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
