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

Under nourished persons - nutritional intervention using mna, Define Under ...

Define Under nourished persons - nutritional intervention using MNA? An MNA score below 17 indicates that the patient is suffering from under nutrition.  Thus in this situatio

Proteins requirements for ulcerative colitis, Q. Proteins requirements for ...

Q. Proteins requirements for ulcerative colitis? Proteins: Patients with ulcerative colitis lose about 4-8 g fecal N2 as compared to the normal excretion of 2 g. In severe ulce

The cell cycle, what happens to the liver cell during the cell cycle

what happens to the liver cell during the cell cycle

Define application of nutrition knowledge in geld of sports, Define Applica...

Define Application of Nutrition Knowledge in Geld of Sports? By the time you are ready to do this unit, you have been exposed to a good deal of the basic knowledge of nutrition

What is a plant-incorporated protectant, What is a plant-incorporated prote...

What is a plant-incorporated protectant? Plant-incorporated protectants are pesticidal substances formed and used by the living plant, typically to protect the plant from pests

What are the habits of patients- implants, Habits of patients- Implants ...

Habits of patients- Implants Smoking has been shown to predispose to poor bone quality by reduced vascularity. Therefore it is prudent not to accept heavy smokers as implant pa

Contamination of the implant body before insertion, Contamination of the Im...

Contamination of the Implant Body before Insertion The implant may be contaminated by manufacturing error, by the operator, from non titanium instrumentation and by the bacteri

Why is it necessary to maintain the ph level, Q Coming from the acid pH of ...

Q Coming from the acid pH of the stomach which pH level does the chyme find when it enters the duodenum? Why is it necessary to maintain that pH level in the small intestine? What

Internal and external respiration, External Respiration: Diffusion of...

External Respiration: Diffusion of oxygen into blood and carbon dioxide into alveoli (external respiration)  is the diffusion of oxygen from air in  the alveoli of lungs to bl

Determine the surgical phase of implant therapy, Stage I Surgical phase ...

Stage I Surgical phase Implant placed in the maxilla or mandible After 7 days: - Sutures resorbs or are removed - Patient may be allowed to wear his/her former denture

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