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 poison cyanide act upon the aerobic respiration, Q. How does t...

Q. How does the poison cyanide act upon the aerobic respiration? Cyanide is a poison that restrains the last cytochrome of the respiratory chain, interrupting the ATP formation

Ethidium bromide, Ethidium Bromide  intercalates within structure of the nu...

Ethidium Bromide  intercalates within structure of the nucleic acids in such a manner that they fluoresce under the UV light. Ethidium bromide staining is generally used to visuali

Microbiology, different applications of microbiology

different applications of microbiology

What is cardio vasular examination in hheart disease, What is cardio vasula...

What is cardio vasular examination in hheart disease? Cardio-vascular examination: A thorough and systematically cardio-vascular examination provides valuable clues to the pr

Dissolved gases and alkalinity, Dissolved Gases and Alkalinity Disso...

Dissolved Gases and Alkalinity Dissolved Gases The marine environment serves as a gigantic reservoir of dissolved oxygen and carbon dioxide, which respectively help reg

What are some examples of biological activities, Q. What are some examples ...

Q. What are some examples of biological activities in which osmosis plays an significant role? Hemolysis destruction of red blood cells by entrance of water, the hydric regulat

Why do vestigial structures persist in modern organisms, Why do vestigial s...

Why do vestigial structures persist in modern organisms? Explain the evidence that indicates that species evolve over time. The environment will not select for or against

Define iron requirements of school children and adolescents, Define Iron re...

Define Iron requirements of school children and adolescents? The iron requirements are also computed by factorial method and should therefore add iron requirement of maintenanc

What are the types of reproduction that occur in fungi, What are the types ...

What are the types of reproduction that occur in fungi? In fungi there are asexual and sexual reproduction. Fungi replicate asexually by fragmentation, gemmation and sporulatio

What is the purpose to use hydrocolloids, Hydrocolloids are extremely versa...

Hydrocolloids are extremely versatile and are used for many other purposes including: (a) Production of pseudoplasticity  (i.e. fluidity under shear) at high temperatures to ea

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