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 future projections in the field of public nutrition, Define Future P...

Define Future Projections in the Field of Public Nutrition? We discussed earlier that the field of public nutrition has existed for a long time, although not by this name. A he

Define precautions for determination of inorganic phosphorus, Define Precau...

Define Precautions for Determination of Inorganic Phosphorus? 1. All reagents should be added in the order mentioned. 2. Allow 10 minutes for the colour to develop in each t

Blood coagulation, BLOOD COAGULATION -   DEFINITIO N - The pro...

BLOOD COAGULATION -   DEFINITIO N - The property of blood to change from fluid to gel state within a few minutes of its coming in contact with air is called blood coag

Factors affecting normal blood sugar levels, Q. Factors Affecting Normal Bl...

Q. Factors Affecting Normal Blood Sugar Levels? Earlier in our discussion, we learnt that insulin is the most important factor responsible for normal blood sugar levels. Now we

What are the endocrine functions of the placenta, Q. What are the endocrine...

Q. What are the endocrine functions of the placenta? The placenta has endocrine function since it secretes the hormones estrogen and progesterone that maintain the endometrium

What respectively are zygotic meiosis, What respectively are zygotic meiosi...

What respectively are zygotic meiosis, gametic meiosis and sporic meiosis? Zygotic meiosis is the one that happens in the haplontic haplobiontic life cycle. Gametes from adult

What is coronary artery disease, Q. What is Coronary artery disease? Nu...

Q. What is Coronary artery disease? Nutrition is a basic prerequisite for maintaining a desirable body weight and that diet has a major role in the prevention and treatment of

Muscular tissue, MUSCULA R TISSUE Muscular tissue in general develop...

MUSCULA R TISSUE Muscular tissue in general develops from the mesoderm of the embryo but the muscles of the iris of the eye and myoepithelial cells of the salivary, mammar

Explain benefits of protein, Explain benefits of Protein Protein: Once ...

Explain benefits of Protein Protein: Once the energy requirements have  been estimated, protein requirements can be addressed. The aim is to achieve nitrogen balance. There are

Explain the types of fats, Jillian and Michael are in their freshman year a...

Jillian and Michael are in their freshman year at college. The two have been friends since grade school and the two of them enjoy getting together for dinner. Michael typically

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