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

What is a chromosomal translocation, Question 1 Write a short note on the ...

Question 1 Write a short note on the following- Plasmids Retrotransposons Hfr Conjugation Generalized transduction Question 2 With the help of a neat diagra

Define estimation of blood thiamin levels - thiamin status, Define Estimati...

Define Estimation of Blood Thiamin Levels - Thiamin Status? The levels of free thiamin and its phosphoesters in whole blood and erythrocytes are measured using high- performanc

Illustrate the functioning of living systems, How are buffers significant t...

How are buffers significant to the functioning of living systems? By neutralizing small amounts of acid or base that might be added to a solution, buffers keep pH values at nor

Synthesis and storage of hormone, Synthesis and Storage of Hormone The...

Synthesis and Storage of Hormone The synthesis and storage of hormone depends on the nature of the hormone. Steroid hormones are secreted in diffuse molecular form and usually

Determine which seed is best for your lawn, Assume that your yard has many ...

Assume that your yard has many tall trees that result in about fifty percent of the yard being shaded and fifty percent of the yard being exposed to full sun. The shaded areas and

What else is carried in the plasma, What else is carried in the plasma? ...

What else is carried in the plasma? In addition to proteins, plasma having salts (ions), glucose, lipids and amino acids, hormones, carbon dioxide and urea

Explain the procedure for preparation of bacterial smear, Explain the Proce...

Explain the Procedure for Preparation of Bacterial Smear? Start the exercise by following the steps enumerated herewith. (1) Take properly washed and dried glass slides for

Mcnaughton case and law, MCNAUGHTON'S CASE AND LAW: In 1843, McNaughto...

MCNAUGHTON'S CASE AND LAW: In 1843, McNaughton shot and  killed Sir Robert Peel's secretary Edward -Drymmond.  It was  shown  that McNaughton suffered from a number of  delusi

Chronic complications of diabetes, Q. Chronic complications of diabetes? ...

Q. Chronic complications of diabetes? These occur gradually when the diabetics do not monitor the blood sugar and they are careless about eating, exercise and the medications a

Biogeochemical cycling - nutrient cycles, Biogeochemical Cycling - Nutrient...

Biogeochemical Cycling - Nutrient Cycles The energy flows through ecosystems enabling the organisms to perform various kinds of work, and is ultimately lost as heat. It is gon

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