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Encyclopedia > Soma (biology)
Soma
Structure of a typical neuron

The soma, or perikaryon, is the bulbous end of a neuron, containing the cell nucleus. It is also known as the cell body. The word soma is Greek, meaning "body"; the soma of a neuron is often called the "cell body". There are many different specialized types of neurons and the size of the soma can range from about 5 micrometres to over 1 millimetre for some of the largest neurons of invertebrates. Image File history File links Neuron-no_labels. ... Dendrites (from Greek dendron, “tree”) are the branched projections of a neuron that act to conduct the electrical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project. ... An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... HeLa cells stained for DNA with the Blue Hoechst dye. ... Nodes of Ranvier are regularly spaced gaps in the myelin sheath around an axon or nerve fiber. ... Nodes of Ranvier are regularly spaced gaps in the myelin sheath around an axon or nerve fiber. ... Illustration of the major elements in a prototypical synapse. ... Named after the German physiologist Theodor Schwann, Schwann cells are a variety of neuroglia that mainly provide myelin insulation to axons in the peripheral nervous system of jawed vertebrates. ... In neuroscience, myelin is an electrically insulating fatty layer that surrounds the axons of many neurons, especially those in the peripheral nervous system. ... Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ... HeLa cells stained for DNA with the Blue Hoechst dye. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ... Invertebrate is an English word that describes any animal without a spinal column. ...


The cell nucleus is a key feature of the soma. The nucleus is the source of most of the RNA that is produced in neurons and most proteins are produced from mRNAs that do not travel far from the nucleus. This creates a challenge for supplying new proteins to axon endings that can be a meter or more away from the soma. Axons contain microtubule-associated motor proteins that transport protein-containing vesicles between the soma and the synapses at the axon terminals. Such transport of molecules towards and away from the soma maintains critical cell functions. Ribonucleic acid or RNA is a nucleic acid polymer consisting of nucleotide monomers that plays several important roles in the processes that translate genetic information from deoxyribonucleic acid (DNA) into protein products; RNA acts as a messenger between DNA and the protein synthesis complexes known as ribosomes, forms vital portions... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... The interaction of mRNA in a eukaryote cell. ... An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... Microtubules are one of the components of the cytoskeleton. ... This is a list of gene families or gene complexes, that is sets of genes which occur across a number of different species which often serve similar biological functions. ... This article or section is in need of attention from an expert on the subject. ... Illustration of the major elements in a prototypical synapse. ...


The survival of some sensory neurons depends on axon endings making contact with sources of survival factors that prevent apoptosis. The survival factors are neurotrophic factors, including molecules such as nerve growth factor (NGF). NGF interacts with receptors at axon terminals, and this produces a signal that must be transported up the length of the axon to the nucleus. A current theory of how such survival signals are sent from axon endings to the soma includes the idea that NGF receptors are endocytosed from the surface of axon tips and that such endocytotic vesicles are transported up the axon. [1] The mechanism of the reflex arc Sensory neurons (neurones) are nerve cells within the nervous system responsible for converting external stimuli from the organisms environment into internal electrical motor reflex loops and several forms of involuntary behavior, including pain avoidance. ... A section of mouse liver showing an apoptotic cell indicated by an arrow // Apoptosis is a process of deliberate life relinquishment by a cell in a multicellular organism. ... Neurotrophins are a family of molecules that encourage survival of nervous tissue. ... Nerve growth factor (NGF), is a small secreted protein which induces the differentiation and survival of particular target neurons (nerve cells). ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm that binds to a specific factor (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ... It has been suggested that Endocytic cycle be merged into this article or section. ...


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  Results from FactBites:
 
Reference.com/Encyclopedia/Soma (biology) (321 words)
The soma, or perikaryon, is the bulbous end of a neuron, containing the cell nucleus.
The word soma is Greek, meaning "body"; the soma of a neuron is often called the "cell body".
A current theory of how such survival signals are sent from axon endings to the soma includes the idea that NGF receptors are endocytosed from the surface of axon tips and that such endocytotic vesicles are transported up the axon.
Somatics Library: What is Somatics? Part II (3636 words)
Biology is misleading unless it views individual life forms against the surrounding relativistic cosmos out of which they arose and with which they must constantly pattern their activities.
Somas are not “bodies”; rather, they are processes of patterned movements which deceive the third-person observer with the appearance of being substantial structured bodies because of the constancy of these movement patterns.
Somas were inevitable because the seeds of their possibility were implanted in the original core of the cosmos, and the expansion and differentiation of the cosmos would inevitably produce that combination of factors which would bring this seed to life.
  More results at FactBites »

 
 

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