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Edward George Gray
Edward George Gray (1924–1999) was a British anatomist and neuroscientist who pioneered the investigation of neural tissues with transmission electron microscopy. During his professional career, Gray made a number of profound contributions to our knowledge of synaptic structure. To this day, synapses are classified according to their ultrastructure as Gray type 1 (asymmetric) or type 2 (symmetric), corresponding to inhibitory and excitatory synapses. Life and major contributions Edward G. Gray came to the Anatomy Department at University College London (UCL) in 1955 to work as a postdoctoral assistant to John Z. Young. In 1959, he published a seminal paper on the synaptic structure in mammalian neocortex, describing a specialized organelle inside dendritic spines that he named the spine apparatus. In 1962, he published a method for isolating synaptosomes which are isolated axon terminals purified by centrifugation. In 1970, he described the clathrin coats of recycling vesicle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Microscope
An electron microscope is a microscope that uses a beam of electrons as a source of illumination. It uses electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam, for instance focusing it to produce magnified images or electron diffraction patterns. As the wavelength of an electron can be up to 100,000 times smaller than that of visible light, electron microscopes have a much higher Angular resolution, resolution of about 0.1 nm, which compares to about 200 nm for optical microscope, light microscopes. ''Electron microscope'' may refer to: * Transmission electron microscopy, Transmission electron microscope (TEM) where swift electrons go through a thin sample * Scanning transmission electron microscopy, Scanning transmission electron microscope (STEM) which is similar to TEM with a scanned electron probe * Scanning electron microscope (SEM) which is similar to STEM, but with thick samples * Electron microprobe sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptosome
A synaptosome is an isolated synaptic terminal from a neuron. Synaptosomes are obtained by mild homogenization of nervous tissue under isotonic conditions and subsequent fractionation using differential and density gradient centrifugation. Liquid shear detaches the nerve terminals from the axon and the plasma membrane surrounding the nerve terminal particle reseals. Synaptosomes are osmotically sensitive, contain numerous small clear synaptic vesicles, sometimes larger dense-core vesicles and frequently one or more small mitochondria. They carry the morphological features and most of the chemical properties of the original nerve terminal. Synaptosomes isolated from mammalian brain often retain a piece of the attached postsynaptic membrane, facing the active zone. Synaptosomes were first isolated in an attempt to identify the subcellular compartment corresponding to the fraction of so-called bound acetylcholine that remains when brain tissue is homogenized in iso-osmotic sucrose. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Anatomists
British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture * British English, the English language as spoken and written in United Kingdom of Great Britain and Northern Ireland and, more broadly, throughout the British Isles * Celtic Britons, an ancient ethno-linguistic group * Brittonic languages, a branch of the Insular Celtic language family (formerly called British) ** Common Brittonic, an ancient language Other uses *People or things associated with: ** Great Britain, an island ** British Isles, an island group ** United Kingdom, a sovereign state ** British Empire, a historical global colonial empire ** Kingdom of Great Britain (1707–1800) ** United Kingdom of Great Britain and Ireland (1801–1922) * British Raj, colonial India under the British Empire * British Hong Kong, colonial Ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1924 Births
Events January * January 12 – Gopinath Saha shoots Ernest Day, whom he has mistaken for Sir Charles Tegart, the police commissioner of Calcutta, and is arrested soon after. * January 20–January 30, 30 – Kuomintang in China holds its 1st National Congress of the Kuomintang, first National Congress, initiating a policy of alliance with the Soviet Union and the Chinese Communist Party. * January 21 – Alexander Cambridge, 1st Earl of Athlone, The Earl of Athlone is appointed Governor-General of the Union of South Africa, and High Commissioner for Southern Africa.Archontology.org: A Guide for Study of Historical Offices: South Africa: Governors-General: 1910-1961 (Accessed on 14 April 2017) * January 22 – R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Association For Anatomy
The American Association for Anatomy (AAA), is an international scientific society of Biomedical research, biomedical researchers and educators committed to advancing anatomical science through research, education, and professional development. Headquartered in Rockville, Maryland, the association was established in 1888 in Washington, D.C., as the Association of American Anatomists to promote the "advancement of anatomical science." It was renamed in 1908 as the American Association of Anatomists, before adopting its current name in 2019 to reflect the evolving scope of anatomical science and its interdisciplinary reach. AAA's membership comprises professionals specializing in the structural and functional foundations of health and disease. Its members play a central role in educating students in the health professions, particularly during their foundational training. In addition to teaching, AAA members conduct research in a broad range of fields, including Medical imaging, im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, recognising excellence in science, supporting outstanding science, providing scientific advice for policy, education and public engagement and fostering international and global co-operation. Founded on 28 November 1660, it was granted a royal charter by Charles II of England, King Charles II and is the oldest continuously existing scientific academy in the world. The society is governed by its Council, which is chaired by the society's president, according to a set of statutes and standing orders. The members of Council and the president are elected from and by its Fellows, the basic members of the society, who are themselves elected by existing Fellows. , there are about 1,700 fellows, allowed to use the postnominal title FRS (Fellow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synaptic Vesicle
In a neuron, synaptic vesicles (or neurotransmitter vesicles) store various neurotransmitters that are exocytosis, released at the chemical synapse, synapse. The release is regulated by a voltage-dependent calcium channel. Vesicle (biology), Vesicles are essential for propagating nerve impulses between neurons and are constantly recreated by the cell (biology), cell. The area in the axon that holds groups of vesicles is an axon terminal or "terminal bouton". Up to 130 vesicles can be released per bouton over a ten-minute period of stimulation at 0.2 Hz. In the visual cortex of the human brain, synaptic vesicles have an average diameter of 39.5 nanometers (nm) with a standard deviation of 5.1 nm. Structure Synaptic vesicles are relatively simple because only a limited number of proteins fit into a sphere of 40 nm diameter. Purified vesicles have a protein:phospholipid ratio of 1:3 with a lipid composition of 40% phosphatidylcholine, 32% phosphatidylethanola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrifugation
Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The denser components of the mixture migrate away from the axis of the centrifuge, while the less dense components of the mixture migrate towards the axis. Chemists and biologists may increase the effective gravitational force of the test tube so that the precipitate (pellet) will travel quickly and fully to the bottom of the tube. The remaining liquid that lies above the precipitate is called a supernatant or supernate. There is a correlation between the size and density of a particle and the rate that the particle separates from a heterogeneous mixture, when the only force applied is that of gravity. The larger the size and the larger the density of the particles, the faster they separate from the mixture. By applying a larger effective gravitational force to the mixture, like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axon Terminal
Axon terminals (also called terminal boutons, synaptic boutons, end-feet, or presynaptic terminals) are distal terminations of the branches of an axon. An axon, also called a nerve fiber, is a long, slender projection of a Neuron, nerve cell that conducts electrical impulses called action potentials away from the neuron's cell body to transmit those impulses to other neurons, muscle cells, or glands. Most presynaptic terminals in the central nervous system are formed along the axons (en passant boutons), not at their ends (terminal boutons). Functionally, the axon terminal converts an electrical signal into a chemical signal. When an action potential arrives at an axon terminal (A), neurotransmitter, the neurotransmitter is released and diffuses across the synaptic cleft. If the postsynaptic cell (B) is also a neuron, Neurotransmitter receptor, neurotransmitter receptors generate a small electrical current that changes the postsynaptic potential. If the postsynaptic cell (B) is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spine Apparatus
The spine apparatus (SA) is a specialized form of endoplasmic reticulum (ER) that is found in a subpopulation of dendritic spines in central neurons. It was discovered by Edward George Gray in 1959 when he applied electron microscopy to fixed cerebral cortex, cortical tissue. The SA consists of a series of stacked discs that are connected to each other and to the dendritic system of ER-tubules. The actin binding protein synaptopodin (which was originally described in podocytes of the kidney) is an essential component of the SA. Mice that lack the gene for synaptopodin do not form a spine apparatus. The SA is believed to play a role in synaptic plasticity, learning and memory, but the exact function of the spine apparatus is still enigmatic. Morphology The spine apparatus consists of membranous saccules (discs) and tubules surrounded by wispy filamentous material and is mainly found in large mushroom-shaped dendritic spine, dendritic spines. The wispy filamentous material is the cyto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapse
In the nervous system, a synapse is a structure that allows a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending on the mechanism of signal transmission between neurons. In the case of electrical synapses, neurons are coupled bidirectionally with each other through gap junctions and have a connected cytoplasmic milieu. These types of synapses are known to produce synchronous network activity in the brain, but can also result in complicated, chaotic network level dynamics. Therefore, signal directionality cannot always be defined across electrical synapses. Chemical synapses, on the other hand, communicate through neurotransmitters released from the presynaptic neuron into the synaptic cleft. Upon release, these neurotransmitters bind to specific receptors on the postsynaptic membrane, inducing an electrical or chemical response in the target neuron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendritic Spine
A dendritic spine (or spine) is a small membrane protrusion from a neuron's dendrite that typically receives input from a single axon at the synapse. Dendritic spines serve as a storage site for synaptic strength and help transmit electrical signals to the neuron's cell body. Most spines have a bulbous head (the spine head), and a thin neck that connects the head of the spine to the shaft of the dendrite. The dendrites of a single neuron can contain hundreds to thousands of spines. In addition to spines providing an anatomical substrate for memory storage and synaptic transmission, they may also serve to increase the number of possible contacts between neurons. It has also been suggested that changes in the activity of neurons have a positive effect on spine morphology. Structure Dendritic spines are small with spine head volumes ranging 0.01 μm3 to 0.8 μm3. Spines with strong synaptic contacts typically have a large spine head, which connects to the dendrite via a m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
