Conduction in myelinated axons, Biology

Assignment Help:

Conduction in Myelinated Axons

The myelin sheath provides insulation for the axon preventing movements of Na+ and K+ through the membrane. Therefore, if this myelin sheath was continuous no action potential would be generated. Fortunately, gaps or nodes of Ranvier occur in the myelin. Since the cable properties of axon can conduct depolarisations over very short distance (1-2 mm), the nodes of Ranvier must be close together (actually they are 1 mm apart). Studies have shown that the Na+ channels are concentrated at the nodes and absent from the regions between two nodes. Action potential therefore occurs only at the nodes of Ranvier and seems to leap from node to node. This is called saltatory conduction. The spread of depolarisation between the nodes is very fast and fewer action potentials are needed. Therefore, the rate of conduction is much faster than in unmyelinated fibres.

This peculiar structure and mode of conduction in myelinated fibres is responsible for the fast conduction of impulses in motor nerves of vertebrates even though the nerves are very thin. The greatest advantage of myelinated fibres comes from their smaller size and so a highly complex nervous system with high conduction velocities can occur without occupying too much of space.


Related Discussions:- Conduction in myelinated axons

How does the heart impel the blood, Q. How does the heart impel the blood? ...

Q. How does the heart impel the blood? The heart is a muscular organ that contains chambers right ventricle and right atrium right ventricle and and left atrium through which b

Describe plasmid functions to bring about resistance, E. coli strains conta...

E. coli strains containing the plasmid pAMP are resistant to ampicillin. Describe how this plasmid functions to bring about resistance.

How are the proteins important in metabolism of lens, How are the proteins ...

How are the proteins important in metabolism of lens? Proteins Physical slate of protein is important for transparency of lens. Morner first time classified protein of l

Diversty of living organisms, write down the division of cryptogamae and p...

write down the division of cryptogamae and phanerogamae

What are gonads, What are gonads? What are the male and the female gonads i...

What are gonads? What are the male and the female gonads in humans? Gonads are the organs that make gametes. They have the germ cells that undergo division and generate gametes

Electric charge between neuron plasma membrane, Q. Which is the normal sign...

Q. Which is the normal sign of the electric charge between the two sides of the neuron plasma membrane? What is the potential difference (voltage) generated between these two sides

Define requirements of iodine during pregnancy period, Define requirements ...

Define requirements of Iodine during pregnancy period? You would be already aware that maternal iodine deficiency leads to cretinism in the off spring. Hence, the material diet

Define methods of prevention and control of anaemia, Define methods of prev...

Define methods of prevention and control of anaemia? The available methods of prevention and control of anaemia are: Supplementation Food fortification Dietary

Bacteria entering the blood system, Briefly describe the principal lines of...

Briefly describe the principal lines of defence against bacteria entering the blood system. A blood clot forms a barrier to entry by bacteria. White cells ingest and kill bacte

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd