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

Cnidaria and protozoan, What are the advancement of cnidaria over protozoa

What are the advancement of cnidaria over protozoa

Determine about the brain tissue, Determine about the Brain tissue Bra...

Determine about the Brain tissue Brain tissue looks solid to the naked eye (it has a consistency of stiff jelly), so 'finger-grain' investigations had to await two technologic

Define briefly about the cereal proteins, Define briefly about the Cereal P...

Define briefly about the Cereal Proteins? Cereal grains, properly ripened and dried for optimum storage stability, have protein content ranging from 6-20%. Proteins are found i

Illustrate the functioning of comprehensive model, Illustrate the functioni...

Illustrate the functioning of comprehensive model 1) Provide continuity in understanding developmental progress, or lack thereof, in those disorders that affect neurological de

Mode of hormone action through extracellular receptors, MOD E OF HORMONE A...

MOD E OF HORMONE ACTION THROUGH EXTRACELLULAR RECEPTORS - The molecules of amino acid derivatives, peptides or polypeptide (protein) hormones bind to specific receptor molecul

Can you explain metallized films, Q. Can you explain Metallized films? ...

Q. Can you explain Metallized films? In metallized films, plastic films such as those of polyester, polyamide and polypropylene are coated with aluminium to enhance the barri

What is the neuromuscular synapse, What is the neuromuscular synapse? N...

What is the neuromuscular synapse? Neuromuscular synapse is the structure by which the neural impulse passes from the axon of a motor neuron to the muscle cell. This structure

Excretory system, What are the excretory organ in protozoa,coelenterates, i...

What are the excretory organ in protozoa,coelenterates, insects,spider,and arthropods

Echinoderms, Phylogenetic considerations

Phylogenetic considerations

What is law or theory of demand state, What is law or theory of demand stat...

What is law or theory of demand state? The law or theory of demand states as consumers we derive satisfaction or ‘utility’ like a result of consuming a good or a service. It va

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