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

Rbc & wbc, difference between RBC and WBC for homework

difference between RBC and WBC for homework

Six-membered oxygen-containing ring is referred as, A cyclic hemiacetal wit...

A cyclic hemiacetal with a six-membered oxygen-containing ring is referred to as a(n): Select one: a. aldehyde. b. pyranose. c. ketopentose. d. furanose. e. sorbi

In high altitudes is it necessary for the blood to have more, In high altit...

In high altitudes is it necessary for the blood to have more or less hemoglobin? In high altitudes the air is rarefied and oxygen concentration is lower than in low altitudes.

Inverse pcr, Inverse PCR is the variation of PCR which makes the amplifica...

Inverse PCR is the variation of PCR which makes the amplification of DNA segments of unknown sequence that flank DNA segments of the known sequence possible; in short, total DNA i

Experiment turn out differently then you expected, If the results of an exp...

If the results of an experiment turn out differently then you expected, what does that mean? A. The experiment was a failure B. You did not follow scientific method C. You should e

Are the alleles of a gene essentially originated, Are the alleles of a gene...

Are the alleles of a gene essentially originated one from the father and the other from the mother? Are there exceptions? It is natural so that alleles have come one from the m

Define classification of carbohydrates - monosaccharide, Define Classificat...

Define Classification of Carbohydrates - Monosaccharide? Monosaccharides or simple sugars are those carbohydrates that cannot be hydrolyzed into simpler carbohydrates. E.g. gl

Explain risk factor global perspective in heart dieases, Explain risk facto...

Explain risk factor at the global perspective in heart diease? While the risk of Cardio-vascular diseases has been found to be variable in different ethnic groups with the high

Are gametes always made by meiosis, Q. Are gametes always made by meiosis? ...

Q. Are gametes always made by meiosis? In the haplontic haplobiontic life cycle and in the plant life cycle (diplobiontic life cycle) gametes are made by mitosis and not by mei

Timber, introduction,types,uses and characteristics of a good timber?

introduction,types,uses and characteristics of a good timber?

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