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

Define some symptoms of epilepsy, Define some Symptoms of Epilepsy? The...

Define some Symptoms of Epilepsy? The general symptoms of epilepsy include weakness, fainting, uncoordinated muscle movement. Based on the drug, common side effects include nau

What are quantitative data, What are quantitative data? Give two examples o...

What are quantitative data? Give two examples of quantitative data. Quantitative data are data that can be calculated in numbers. Examples contain the dimensions of an objec

Symmetry system characterized in echinoderms, Q. How are the nervous and th...

Q. How are the nervous and the symmetry system characterized in echinoderms? Adult echinoderms, along with cnidarians, are the animals that present radial symmetry that is thei

State the goals of neuropsychological assessment, State the Goals of neurop...

State the Goals of neuropsychological assessment The psychological domains/processes/ components are mediated by specific brain structures and connected brain structures formin

Dna replication in bacteria, The DNA replication is a biological procedure ...

The DNA replication is a biological procedure which happens in all living organisms and copies their DNA; it is the basis for biological inheritance. The process will starts when o

Name the foods to avoid in soft diet, Name the Foods to avoid  in soft die...

Name the Foods to avoid  in soft diet include: Fried foods and nuts, rich pastries and desserts, Raw  vegetables, Heavily spiced foods, Gas-forming vegetables, S

Hydrostatic skeleton, Hydrostatic Skeleton The functioning of the hyd...

Hydrostatic Skeleton The functioning of the hydrostatic skeleton in an animal depends upon the musculature being arranged around an enclosed volume of fluid. After that, cont

Menstrual cycle in human beings, Menstrual cycle in human beings: 1) Th...

Menstrual cycle in human beings: 1) The cycle of changes in the female reproductive system that leads to formation of Ovum is called 'menstrual cycle'. It occurs once in 28 to

Explain the alterations occuring in cereal, Alterations occuring in cereal ...

Alterations occuring in cereal & cereal products, legumes You are already aware of the chemical composition of cereals and pulses.  We will now look into changes occurring in t

What is the action mechanism of the antibiotic penicillin, What is the acti...

What is the action mechanism of the antibiotic penicillin? Penicillin, discovered by the Scottish doctor Alexander Fleming in 1928, is a drug that inhibits enzymes essential fo

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