Upon development, the nervous system wires itself completely – an impressive feat considering the millions of connections and neurons in the body. However perhaps even more impressive is the ability of the nervous system to restore neuronal connections after injury. This is particularly advanced in frogs, fish and invertebrates as once an axon is cut in the central nervous system, the regeneration allows full functional recovery whereas in the mammalian central nervous system full recovery is not always possible. Unfortunately, the reason for the lack of molecular signals that render these processes redundant are not currently known, however, there is much we can learn from other species that naturally regenerate neurons resulting in fully
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Macrophages are large phagocytic cells that are important members of the immune system and are created upon occurrence of damage or infection whilst microglial cells (also important members of the immune system) are resident cells and so act as a first response. Meanwhile, the microglial cells and macrophages from elsewhere migrate towards the site of the lesion at around 300micrommeters an hour. Once there is a significant number, they are able to accumulate and phagocytize damaged tissue. During experiments using antibody staining we have been able to see that the microglial cells produces Laminin at the site of trauma – a molecule that encourages neurons to outgrow in vertebrates and …show more content…
In the vertebrate peripheral nervous system an environment is produced that is conducive to axon generation. This environment is due to schwann cells and their secretion of neurotrophic factors NGF and BDNF (brain derived neurotrophic factor) for which they also have receptors on their cell surface membrane in order to molecules in place as the axon is regenerating. In contrast the mammalian central nervous system has a very limited capacity for regeneration and when axons are cut, particularly major axons, the regrowth of the axon concerned is not possible. However, the undamaged axons are fortunately able to sprout new outgrowths which can grow for u to distances of several centimetres and form new synapses which brings about some form of returned
Macrophages are large phagocytic cells that are important members of the immune system and are created upon occurrence of damage or infection whilst microglial cells (also important members of the immune system) are resident cells and so act as a first response. Meanwhile, the microglial cells and macrophages from elsewhere migrate towards the site of the lesion at around 300micrommeters an hour. Once there is a significant number, they are able to accumulate and phagocytize damaged tissue. During experiments using antibody staining we have been able to see that the microglial cells produces Laminin at the site of trauma – a molecule that encourages neurons to outgrow in vertebrates and …show more content…
In the vertebrate peripheral nervous system an environment is produced that is conducive to axon generation. This environment is due to schwann cells and their secretion of neurotrophic factors NGF and BDNF (brain derived neurotrophic factor) for which they also have receptors on their cell surface membrane in order to molecules in place as the axon is regenerating. In contrast the mammalian central nervous system has a very limited capacity for regeneration and when axons are cut, particularly major axons, the regrowth of the axon concerned is not possible. However, the undamaged axons are fortunately able to sprout new outgrowths which can grow for u to distances of several centimetres and form new synapses which brings about some form of returned