Soma (biology): Facts, Discussion Forum, and Encyclopedia Article

Soma (biology)

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	Topics Soma (biology) Topic Home The soma, or perikaryon, is the bulbous end of a neuronNeuron Neurons are a major class of cells in the nervous system.... , containing the cell nucleusCell nucleus In cell biology, the nucleus is an organelle found in most eukaryotic cells.... . The word soma is GreekGreek language Summary Greek has a documented history of 3,500 years, the longest of any single language within the Indo-European family.... , meaning "body"; the soma of a neuron is often called the "cellCell (biology) The cell is the structural and functional unit of all living organisms, and is sometimes called the "building block of life.... body". There are many different specialized types of neurons and the size of the soma can range from about 3 micrometreMicrometre A micrometre is an SI unit of length equal to one millionth of a metre, or about a tenth of the size of a droplet of mist o... s to over 1 millimetre for some of the largest neurons of invertebrateInvertebrate Overview Invertebrate is a term coined by Jean-Baptiste Lamarck to describe any animal without a spinal column.... s. The cell nucleus is a key feature of the soma. The nucleus is the source of most of the RNAFacts About RNA Ribonucleic acid is a nucleic acid polymer consisting of nucleotide monomers.... that is produced in neurons and most proteinProtein Proteins are large organic compounds made of amino acids arranged in a linear chain and joined by peptide bonds.... s are produced from mRNAs that do not travel far from the nucleus. This creates a challenge for supplying new proteins to axonAxon Summary An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, that conducts electrical impulses aw... endings that can be a meter or more away from the soma. Axons contain microtubuleMicrotubule Microtubules are protein structures found within cells, one of the components of the cytoskeleton.... -associated motor proteins that transport protein-containing vesicleVesicle (biology) In cell biology, a vesicle is a relatively small and enclosed compartment, separated from the cytosol by at least one lipid ... s between the soma and the synapses at the axon terminals. Such transport of molecules towards and away from the soma maintains critical cell functions. The survival of some sensory neuronSensory neuron Overview Sensory neurons are nerve cells within the nervous system responsible for converting external stimuli from the organism's en... s depends on axon endings making contact with sources of survival factors that prevent apoptosisApoptosis In biology, apoptosis is one of the main types of programmed cell death .... . The survival factors are neurotrophic factors, including molecules such as nerve growth factorNerve growth factor Nerve growth factor, the prototypical growth factor, is a protein secreted by a neuron's target.... (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 endocytosedEndocytosis Endocytosis is a process whereby cells absorb material from the outside by engulfing it with their cell membrane.... from the surface of axon tips and that such endocytotic vesicles are transported up the axon.