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

Endocrine system, INTRODUCTIO N - Endocrinolog y - Study of endocri...

INTRODUCTIO N - Endocrinolog y - Study of endocrine glands, hormones and their effects. Thomas Addison - Father of endocrinology. Described hormonal disease in 1855 kn

Explain about platyhelminth phylum, What are the best known representatives...

What are the best known representatives of the platyhelminth phylum? The most popular representatives of the platyhelminthes are worms that cause human diseases, like taenia an

Explain about the glycoproteins, Explain about the Glycoproteins? Most...

Explain about the Glycoproteins? Most of the naturally occurring conjugated proteins are glycoproteins. Sugar molecules are covalently bound to them, especially those secreted

Modification of performance traits, M o dification of performance traits ...

M o dification of performance traits Modifications to livestock that could influence traits such as growth rate, feed efficiency and meat quality are major goals for livestoc

Explain risk factors and their role in cad, Explain risk factors and their ...

Explain risk factors and their role in cad ? The concept of risk factors constitutes a major advance for developing strategies to prevent CVD. The Framingham Heat Study played

Explain future challenges of connecting models and data, Explain Future cha...

Explain Future challenges of connecting models and data? Since biological systems are complex, models of biological systems are also complex, and matching models and data is a

What is heterophagic intracellular digestion, What is heterophagic intracel...

What is heterophagic intracellular digestion? How is this process accomplished? Heterophagic intracellular digestion is the breaking into minor substances of external substance

Respiration - metabolism of pollen tubes, Respiration - Metabolism of Polle...

Respiration - Metabolism of Pollen Tubes In the unpollinated pistils of Hippeastrum hybridum very high O 2 , tension exists from stigma down through most of the style. During

Determines the concentration of cortisol in the blood plasma, If one determ...

If one determines the concentration of cortisol in the blood plasma to be 10 micrograms/mL and that in a 24 hour period a person excretes 10 mgs of cortisol, calculate the volume o

How does the absence of a nuclear envelope in prokaryotes, How does the abs...

How does the absence of a nuclear envelope in prokaryotes prevent prokaryotes from controlling gene expression by modifying RNA after transcription? Without a nuclear envelope

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