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

List the heterotrophic nutrition in plants, a) List the a variety of modes ...

a) List the a variety of modes of heterotrophic nutrition in plants. b) Define any two modes giving one example of each.

Name element playing significant role in nitrogen fixation, An element play...

An element playing significant role in nitrogen fixation is : 1.  Molybdenum 2. Copper 3. Manganese 4. Zinc An element playing significant role in nitrogen fixation

What is the typical shape of a population growth curve, Q. What is the typi...

Q. What is the typical shape of a population growth curve? How can the biotic potential be represented in the same way graphically? A usual population growth curve number of in

Define simple, Define Simple, Compound, Derived Lipids? Simple lipids ...

Define Simple, Compound, Derived Lipids? Simple lipids are fatty acid esters of glycerol, called triacyglycerols or triglycerides (for e.g. fats and oils) or higher alcohols (

Bioclimatology effect of climate on distribution of organism, Bioclimatolog...

Bioclimatology: This is the study of effect of climate on distribution of organisms. Bioclimatology is the inter-disciplinary field of science which studies the interactions betwe

Describe rna sequence, Q. What is the name of an RNA sequence that codifies...

Q. What is the name of an RNA sequence that codifies one amino acid? Each sequence of three nitrogen-containing basis of RNA that codifies one amino acid is called a codon. The

Types of synovial joint, TYPES OF SYNOVIAL JOINT - 1 .      BALL AND ...

TYPES OF SYNOVIAL JOINT - 1 .      BALL AND SOCKET JOINT - One bone forms a ball like head that fits into a socket formed in the other bone. Movement is possible in al

Parthenogenesis, what are the consequences of parthenogenesis in human life...

what are the consequences of parthenogenesis in human life if humans reproduced through parthenogenesis?

What is the radiographic evaluation, Radiographic Evaluation An intraor...

Radiographic Evaluation An intraoral periapical radiograph with a paralleling technique should be made and observed to ensure absence of pathology in the peri-implant region an

What do you mean by the good and bad cholesterol, Q. What are the so-called...

Q. What are the so-called "good" and "bad" cholesterol? Lipoproteins are complexes made of lipids (cholesterol and triglycerides) and proteins. The lipoproteins present differe

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