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

Keys for identification of taxonomic work, Q. Keys for identification of ta...

Q. Keys for identification of taxonomic work? Identification is an integral part of all taxonomic work. It is the recognition of certain, characters of flower, fruit, leaf or s

Define fat requirements in human body, Define Fat requirements in human bod...

Define Fat requirements in human body? There is no change in fat digestibility at altitude of

Acid rain, What direct or indirect effect is acid rain thought to have on m...

What direct or indirect effect is acid rain thought to have on mama''s and forest and buildings

Signify platelets of blood, Which of the subsequent statements concerning p...

Which of the subsequent statements concerning platelets is INCORRECT. Platelets: a) Are between 1/2 and 1/3 the diameter of the red cell b) Are roughly disk-shaped c) Hav

Consumers-biotic components , Consumers Heterotrophs (other nourishing...

Consumers Heterotrophs (other nourishing) are incapable of photosynthesis and depend on organic food derived from animals, plants or both. Consumers can be divided into two br

Companion cells, Companion cells  are the specialized cells in the phloem w...

Companion cells  are the specialized cells in the phloem which load sugars into the sieve elements and help to maintain a functional plasma membrane in the sieve elements.

What are the properties og gel, What are the properties og Gels? Polysa...

What are the properties og Gels? Polysaccharides, proteins or colloidal complex particles, such as caseinate micelles  form gels at levels of 10% or less. Gums, pectin and gela

Cerebellum, what is the work of cerebellum

what is the work of cerebellum

What are biotic factors, What are biotic factors? The Biotic factors ar...

What are biotic factors? The Biotic factors are living beings (plants, microorganisms and animals) that are part of a given environment.

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