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 is the mesoderm of triploblastic animals formed, Q. How is the mesoderm...

Q. How is the mesoderm (third germ layer) of triploblastic animals formed? The mesoderm shows from differentiation of endodermal cells that cover the dorsal region of the arche

Prove thet nucleic acid is the transforming agent, Fredrick Griffith publis...

Fredrick Griffith published a series of experiments that collectively were dubbed "The Transforming Principle" in 1928. Which of the following stopped him from being able to declar

What are plant hormones, What are plant hormones? Plant hormones, also ...

What are plant hormones? Plant hormones, also known as phytohormones, are substances that control the embryonic development and the growth of the adult plant.

What do you understand by hypelglycemia, Q. What do you understand by Hypel...

Q. What do you understand by Hypelglycemia? Hypelglycemia (abnormally high blood sugar): Maintenance of blood glucose levels within or close to the normal range has been stress

Preservation of tooth structure, Q. Preservation of Tooth Structure? Fi...

Q. Preservation of Tooth Structure? Fixed partial dentures have been considered the standard of treatment prior to advent of implant therapy. However, to obtain optimal esthe

Explain metameric in detail., Explain Metameric in detail. A body plan ...

Explain Metameric in detail. A body plan which consists of a series of identical units, metameres, repeated down longitudinal axis of the animal. Every metamere contains identi

The probability of an individual in the trihybrid, The probability of an in...

The probability of an individual in a trihybrid F2 generation showing the dominant phenotype for just two traits?

Define principle for simple staining of bacterial cultures, Define Principl...

Define Principle for Simple Staining of Bacterial Cultures? In simple staining, a single staining agent preferably a basic dye is used. Commonly used basic stains are carbol fu

Define the causes of failures of root canal treatment, Define the Causes of...

Define the Causes of Failures of Root Canal Treatment 1. Errors in diagnosis and treatment planning 2. Coronal leakage ( inadequate restorative protection) 3. Lack of kno

Portion of double-stranded dna, Suppose that a portion of double-stranded D...

Suppose that a portion of double-stranded DNA in the middle of a large gene is being transcribed by an RNA polymerase. As the polymerase moves through the sequence of six bases sho

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