Myelinated fibre, Biology

Assignment Help:

Myelinated fibre

Axon is a relatively long process (also quite often referred to as nerve fibre) and can be considered as functionally specialised for conduction of excitation over considerable distances. In vertebrates the axons of high velocity neurons are covered by insulating sheaths of lipid containing myelin. This myelin is made up of special glial cells -the Schwann cells. The myelin covering is not continuous. There are tiny uninsulated gaps between adjacent Schwann cells. These are the-nodes of Ranvier. The myelin covering and nodes of Ranvier help accelerate the speed of conduction of impulses by a mechanism which we will discuss later. The terminal part of the axon branches, terminating into small ramifications whose tips form end knobs which synaptically contact with other nerve cells. In the end knobs are present characteristic structures called synaptic vesicles which contain and store chemical substances called neurotransmitters.

349_Myelinated fibre.png

Figure: Myelinated fibre

The diversity in neuron form, however so much that is there can be many variations from the generalized description given above. For example, the nerve cells called amacrine cells found in retina contain processes without a demonstrable axon.


Related Discussions:- Myelinated fibre

Risk management option assessment, Risk management option assessment : ...

Risk management option assessment : Identification of available management options Selection of preferred management option , including consideration of an appropriate saf

Write in 5-6 lines about food pyramid, Write in 5-6 lines about food pyrami...

Write in 5-6 lines about food pyramid. The diabetes food pyramid divides food into six groups. These groups vary with each other on the basis of si-e occupied in the pyramid.

Floral induction, Floral Induction The transformation of vegetative ap...

Floral Induction The transformation of vegetative apex into a floral apex is a multifactor and multistep phenomenon. Despite researches on flowering carried out during the las

Meroblastic or partial cleavage, Meroblastic or partial cleavage The e...

Meroblastic or partial cleavage The egg does not divide totally because divisions are restricted to only a part of the egg where as the rest of the egg remains completely uncl

What do you understand by parapodia, What do you understand by Parapodia? ...

What do you understand by Parapodia? Paired lateral, unjointed appendages of polychaete worms. Parapodia have a variety of shapes, and their appearance is related to their nume

What are the mitochondria, Q. What are the mitochondria? What is the fundam...

Q. What are the mitochondria? What is the fundamental morphology of these organelles and in which cells can they be found? Mitochondria are the organelles in which the most sig

Cells, true or false. the law of entropy says that all energy is ultimately...

true or false. the law of entropy says that all energy is ultimately derived from the sun

Explain the concerns of genetically modified (gm) foods, Normal 0 ...

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

Conduction of impulse, CONDUCTIO N OF IMPULSE - IN NON-MYELINATED AXO...

CONDUCTIO N OF IMPULSE - IN NON-MYELINATED AXONS - The impulse moves along the axon as local effect by altering the permeability of neighbouring Na +  channels and af

Taxonmy, classification on taxonomy

classification on taxonomy

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