Soma (biology)

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Soma (biology)

The soma, or cyton or perikaryon, is the bulbous end of a neuron

Neuron

Neurons are responsive cell in the nervous system that process and transmit information by electrochemical Signal . They are the core components of the brain, the vertebrate spinal cord, the invertebrate ventral nerve cord, and the peripheral nerves....
, containing the cell nucleus

Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
. The word soma is Greek

Greek language

Greek is an Indo-European languages native to the southern Balkan peninsula, the language of the Greek people. It forms an independent branch within Indo-European....
, meaning "body"; the soma of a neuron is often called the "cell

Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
body". There are many different specialized types of neurons and the size of the soma can range from about 3 micrometre

Micrometre

A micrometre or micron is one Micro- of a metre, or equivalently one thousandth of a millimetre. It is also commonly known as a micron....
s to over 1 millimetre for some of the largest neurons of invertebrate

Invertebrate

An invertebrate is an animal lacking a vertebral column. The group includes 98% of all animal species ? all animals except those in the Chordate subphylum vertebrate ....
s.

The cell nucleus is a key feature of the soma.

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Encyclopedia

The soma, or cyton or perikaryon, is the bulbous end of a neuron

Neuron

Cell nucleus

In cell biology, the nucleus , also sometimes referred to as the "control center", is a membrane-enclosed organelle found in all eukaryote cell ....
. The word soma is Greek

Greek language

Cell (biology)

Micrometre

Invertebrate

RNA

Ribonucleic acid is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nucleobase, a ribose sugar, and a phosphate....
that is produced in neurons and most protein

Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
s are produced from mRNAs that do not travel far from the nucleus. This creates a challenge for supplying new proteins to axon

Axon

An axon or nerve fiber is a long, slender projectionof a nerve cell, or neuron, that conducts action potentialaway from the neuron's cell body or soma....
endings that can be a meter or more away from the soma. Axons contain microtubule

Microtubule

Microtubules are one of the components of the cytoskeleton. They have a diameter of 25 Nanometre and length varying from 200 nanometers to 25 micrometers....
-associated motor proteins that transport protein-containing vesicle

Vesicle (biology)

A vesicle is a small bubble of liquid within a cell. More technically, a vesicle is a small, intracellular, membrane-enclosed sac that stores or transports substances within a cell....
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 neuron

Sensory neuron

Sensory neurons or also known as afferent neurons are neurons that are activated by sensory input , and send projections into the central nervous system that convey sensory information to the brain or spinal cord....
s depends on axon endings making contact with sources of survival factors that prevent apoptosis

Apoptosis

Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Programmed Cell death involves a series of biochemical events leading to a characteristic cell Morphology and death, in more specific terms, a series of biochemical events that lead to a variety of morphological changes, including Bleb , changes...
. The survival factors are neurotrophic factors, including molecules such as nerve growth factor

Nerve growth factor

Nerve growth factor , is a small secreted protein which induces the Cellular differentiation and survival of particular target neurons . It is perhaps the prototypical growth factor, in that it is one of the first to be described ? that work by Rita Levi-Montalcini and Stanley Cohen was rewarded with a Nobel Prize....
(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

Endocytosis

Endocytosis is the process by which cell s absorb material from outside the cell by engulfing it with their cell membrane. It is used by all cells of the body because most substances important to them are large Chemical polarity molecules that cannot pass through the hydrophobic plasma membrane or cell membrane....
from the surface of axon tips and that such endocytotic vesicles are transported up the axon.

External links

- "Slide 3 Spinal cord

Spinal cord

The spinal cord is a long, thin, tubular bundle of neuron and glia that extends from the brain. The brain and spinal cord together make up the central nervous system....
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