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

Explain classification of lipids, Classification of lipids  A general c...

Classification of lipids  A general classification of lipids based on their structural components is presented in table. Such a classification, however, is possibly too rigid f

Sterigmatocystin, These mycotoxins are structurally and biologically relat...

These mycotoxins are structurally and biologically related to the aflatoxins, and like the latter, they cause hepatocarcinogenic activity in animals. Among the organisms that prod

Pericardium, The heart is enclosed in a membranous sac called the pericardi...

The heart is enclosed in a membranous sac called the pericardium. It has two layers- the fibrous pericardium which is the outer layer and the serous pericardium that lies inside th

State the definition of bio-medical waste, State the definition of Bio-medi...

State the definition of Bio-medical waste 'Bio-medical waste' means any solid and/or liquid waste including its container and any intermediate product, which is generated durin

What is pcr and how does pcr works, What is PCR? How does PCR works? Th...

What is PCR? How does PCR works? The PCR, polymerase chain reaction, is a method to synthesize many copies of specific regions of a DNA molecule known as target-regions. Its in

Illistrate the role in reducign activation energy, 1- Describe the function...

1- Describe the function of enzymes in catalyzing biological reactions ? 2-Descride enzymes ' role in reducign activation energy?

Explain phylum rhodophyta, Phylum Rhodophyta (Red algae) 1) The photosy...

Phylum Rhodophyta (Red algae) 1) The photosynthetic pigments include red pigments (phycoerythrin) and blue pigment (phycocyanin) apart from chlorophyll, of which red pigment pr

Explain the biography of pedanius dioscorides, Explain the Biography of Ped...

Explain the Biography of Pedanius Dioscorides? Pedanius Dioscorides, a Cicilian Greek, who lived in the first century A.D. was the most important botanist after Theophrastus. H

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