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

Define functions of carbohydrate - protein sparing effect, Define functions...

Define functions of carbohydrate - Protein sparing effect? Carbohydrates help in regulating the protein metabolism. Presence of sufficient carbohydrates to meet energy demands

Determination of proteins and amino acid content in foods, Define Methods o...

Define Methods of Determination of Proteins and Amino Acid Content in Foods? The methods for protein quality evaluation are grouped under the following headings: I) Analytic

Definition of infective endocarditis, Infective endocarditis (IE) is a micr...

Infective endocarditis (IE) is a microbial infection of the endothelial surface of the heart. The characteristic lesion, the vegetation, is a variably sized amorphous mass of plate

What percentage of sons will show recessive phenotype, A woman who is heter...

A woman who is heterozygous for a particular X-linked recessive trait marries a phenotypically normal man. What percentage of their sons will show the recessive phenotype?

Levels of organization of matter - metazoa, Levels of organization of Matte...

Levels of organization of Matter- Metazoa The smallest structural units of all matter are subatomic particles, mainly electrons, protons and neutrons. The next larger units a

What gases was the earths primitive atmosphere, Before the emergence of lif...

Before the emergence of life of what gases was the earth's primitive atmosphere constituted? The earth's primitive atmosphere was basically produced of methane, hydrogen, ammon

Subphylum trilobitomorpha, Subphylum Trilobitomorpha Subphylum Trilobi...

Subphylum Trilobitomorpha Subphylum Trilobitomorpha involves the trilobites. All species are extinct and the fossils point out that they were all marine forms belonging to Pal

What are the three major types of passive transport, Q. What are the three ...

Q. What are the three major types of passive transport? The three main types of passive transport are simple osmosis, diffusion and facilitated diffusion.

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