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

Explain how a human eye is working for the body, Explain how a human eye is...

Explain how a human eye is working for the body. Every tissue in the body requires basic components which are either derived from the body itself or we acquire them from extern

Congenital aortic stenosis-types of aortic stenosis, Congenital Aortic Sten...

Congenital Aortic Stenosis :  The valve may be unicuspid, bicuspid or tricuspid. Rarely it is a dome shaped diaphragm. Uni commissural aortic stenosis produces significant sy

Define the effect of dietary fibre on satiety, Define the effect of Dietary...

Define the effect of Dietary fibre on Satiety? Satiety: Several investigators have speculated that ingestion of a high fibre food induces a feeling of satiety, reduces meal siz

Determine the acidity in the given sample of honey, Q. Determine the acidit...

Q. Determine the acidity in the given sample of honey? This activity will help you to: • carry out the acidity test of the given samples of honey, • learn about the kee

Amniocentesis, Amniocentesis is a way of prenatal testing in which the amn...

Amniocentesis is a way of prenatal testing in which the amniotic fluid is withdrawn from the uterus by the help of a needle. The fluid and the fetal cells it contains are analyzed

Define characteristics of prebiotics, Define characteristics of prebiotics?...

Define characteristics of prebiotics? Characteristics of prebiotics Are non-digestible dietary/food ingredients Are not hydrolyzed/absorbed in the upper GIT, reach

Foods incriminated, Foods that are frequently incriminated in staphylococca...

Foods that are frequently incriminated in staphylococcal food poisoning include meat and meat products, poultry and egg products, egg, tuna, chicken, potato and macaroni, bakery pr

Structural differences between roots and shoots, What are the structural di...

What are the structural differences between roots and shoots? What structures are unique to each?

Amino acids, An amino acid is amphiprotic (have both acid and base)  ...

An amino acid is amphiprotic (have both acid and base)              o    Some are polar, non polar, acidic or basic List of amino acids (red are non-polar, yellow are

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