Download 3-2_UniqueFt_of_Neurons

Unique features of neurons,
which distinguish them from other somatic cells
by Balogh Olivér
1. Structure
- having specialized projections that are used for networking and communication
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dendrites: neurons have multiple dendrites (which also can branch multiple times) that
connect them to other neurons’ axons, the collections of them make the dendritic trees,
most of the incoming information from other neurons go through the dendritic spines (small
membranous protrusions from the dendrites)
axon: one long (depends on the specie and the service site) cable-like projection that only
branches at its destination, where it emerges (axon hillock) from the perikaryon it shows high
density of voltage-dependent sodium channels as this is the place where the action potential
starts and the axon itself carries the nerve signal away from the soma
- supported by special cells and complex mesh of structural proteins
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glial cells: they live in structural and functional symbiosis with the neurons, supporting them
through various ways, including physical protection and regulating the internal environment
(of the brain for example)
neurofilaments: the major component of the neural cytoskeleton, assembled into larger
neurofibrils they provide structural support for the axon
- well developed rough endoplasmatic reticulum system units can be found
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Nissl bodies: visible with basophilic staining in light microscopic preparation, these large
granular bodies consist of RER and associated ribosomal RNA, their primary function is
thought to be synthesis of proteins for intercellular use
2. Function
- the nervous tissue (neurons + glial cells) is responsible for processing the incoming information
from the environment also to regulate the basic functions of the body
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neurons are highly excitable cells, maintaining a -70mV resting potential (due to the uneven
ion distribution) which can be changed (through depolarization) to trigger an action potential
that leads to the release of neurotransmitters
as such, they are able to communicate by neurotransmission using chemical and electrical
synapses
3. Life cycle
- most of the neurons are incapable of self-division and are persist without replacement
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though studies showed that (in the human brain) for a minority of cells the neurogenesis is
possible
also possible for the axons to regrow if they are severed
https://users.itk.ppke.hu/neurobiologia/LECTURES_2016-2017_SEMESTER_1/3.%20WEEK/1.%20HANDOUT/Neurob_7.pdf
https://users.itk.ppke.hu/neurobiologia/LECTURES_2016-2017_SEMESTER_1/3.%20WEEK/1.%20HANDOUT/Neurob_8.pdf
https://users.itk.ppke.hu/neurobiologia/LECTURES_2016-2017_SEMESTER_1/3.%20WEEK/1.%20HANDOUT/Neurob_9.pdf
https://en.wikipedia.org/wiki/Neuron#cite_note-r1-4
https://en.wikipedia.org/wiki/Nissl_body
https://en.wikipedia.org/wiki/Neuroglia