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

Formation of blastopore, Formation of Blastopore The slit such as ope...

Formation of Blastopore The slit such as opening of the initial groove is the opening of the developing blastopore and its dorsal rim is termed as the dorsal lip of blastopor

Synthesis of sucrose, Many of the glyceraldehyde 3-phosphate produced by th...

Many of the glyceraldehyde 3-phosphate produced by the Calvin cycle in chloroplasts is exported to the cytosol and used to produce the disaccharide, sucrose. 1 st the   glyceralde

How different are taenia solium and taenia saginata, Q. Concerning their re...

Q. Concerning their respective intermediate hosts how different are Taenia solium and Taenia saginata? The midway hosts of the Taenia solium are pigs and the intermediate hosts

What is chromosome, Is it possible that an X chromosome of a woman can have...

Is it possible that an X chromosome of a woman can have come from her father? It is not only possible that an X chromosome of a woman is from her father, it is certain. Every w

Explain indications for surgery in aortic aneurysm, Explain Indications for...

Explain Indications for Surgery in Aortic Aneurysm? Indications for Surgery :  Thoracic aortic aneurysms are classified by the portion of aorta involved - ascending, arch,

Define equilibrium conditions in multicomponent systems, Define Equilibrium...

Define Equilibrium Conditions in Multicomponent Systems? This chapter applies equilibrium theory to a variety of chemical systems of more than one component. Two different appr

Describe the factors that affect cardiac, Describe the factors that affect ...

Describe the factors that affect cardiac output in a female athlete who is speed skating toward the finish line in an Olympic race.

Somatic embryogenesis, Somatic Embryogenesis The process of embryo de...

Somatic Embryogenesis The process of embryo development is called embryogenesis. It is not the monopoly of the egg to form an embryo. Any cell of the female gametophyte (Embr

Fossilisation, FOSSILIS A TIO N - The organisms are preserved and...

FOSSILIS A TIO N - The organisms are preserved and fossilized when they are buried in the ice, in an oil rich soil, in the lava of volcano, in swamps, in desiccated deser

Joint, Ask question #Minimum 100 words what is joint accepted#

Ask question #Minimum 100 words what is joint accepted#

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