Neurites, Biology

Assignment Help:

NEURITES -

The processes of neurons are called neurites. These are of two types: dendrites or dendrons and an axon or axis cylinder or neuraxon.

(a)      Dendrites (Dendrons). These are usually shorter, tapering and much branched processes. They may be one to several. The dendrites contain neurofibrils, neurotubules and Nissl's granules. They conduct nerve impulse to- wards the cell body and are called afferent processes (= receiving processes). It's fine branches are telodendria.

(b)      Axon. Axon is a single, usually very long process of uniform thickness. The part of cyton from where the axon arises is called axon hillock.

  • Most sensitive part of neuron is axon hillock.
  • The axon contains neurofibrils and neurotubules but does not have Nissl's granules, Golgi complex, ribosomes, pigment granules, fat globules, etc.
  • In the absence of Nissl's granules, the axon depends on the cell body for the supply of proteins.
  • The cell membrane of the axon is called axolemma and its cytoplasm is known as axoplasm.
  • The axon ends in a group of branches, the terminal arborizations (= axon terminals or telodendria).
  • When terminal arborizations of the axon meet the dendrites of another neuron to form a synapse they form synaptic knobs (= end plates).
  • The synaptic knobs contain mitochondria and secretory vesicles. On muscle fibres and gland cells, the terminal arborizations end as motor end plates.
  • Each axon may also possess lateral or branches called collateral fibres which are usually much finer than the main axonal process.
  • The axon conducts nerve impulses away from the cell body, therefore, called an efferent process.
  • synapse is a site of junction between terminal arborizations of axon of one neuron and the dendrites of
  • another neuron.

2126_structure of nerve fibre or neuron.png

  • Each neuron receives an impulse through its dendrites and passes it on to the next neuron through synapse.
  • A fresh impulse is set up in the dendrites at the synapse with the help of chemicals called neurotransmitters, such as acetylcholine produced by the secretory vesicles of the synaptic knobs.
  • Acetylcholine is the first neurotransmitter to be discovered.

Related Discussions:- Neurites

Temperature - seed dormancy, Temperature - Seed Dormancy Low temperatu...

Temperature - Seed Dormancy Low temperature treatment is an essential prelude to germination in many seeds, and high temperature may be inhibitory at the time of germination.

Explain endocarditis, Explain Endocarditis The risk of endocarditis is ...

Explain Endocarditis The risk of endocarditis is considered high in patients with last bacterial endocarditis, prosthetic heart valves, complex cyanotic congenital heart diseas

Normal pigmentation, The female I-1 and her mate, male I-2, had four childr...

The female I-1 and her mate, male I-2, had four children, one of whom has albinism. What is the probability that they could have had a total of four children with any other outcome

Differences and similarities between nematodes and annelids, Q. What are th...

Q. What are the morphological differences and similarities between nematodes and annelids? Nematodes, like annelids, have a cylindrical elongated body. Annelids differentiate f

Lung abscess, Lung Abscess: Lung  abscess  is a localised collection o...

Lung Abscess: Lung  abscess  is a localised collection of pus in  the pulmonary parenchyma as a result of  suppuration and necrosis. The obstruction  of the bronchus of the in

Explain the determination and application of vitamin e, Explain the Determi...

Explain the Determination of Vitamin E DL-α-Tocopherol is oxidized with ferric chloride and the ferrous ions formed are measured colorimetrially with the aid of α,α'-dipyridyl

What is the optimum temperature for catalyses, What is the optimum temperat...

What is the optimum temperature for catalyses? For any chemical reaction, the reaction rate enhances with temperature, so the higher the temperature, the faster the rate. For a

Excretory organs, why the excretory organ of prawn is called ''green gland'...

why the excretory organ of prawn is called ''green gland''?

Stereoisomers , Glyceraldehyde has a one asymmetric carbon atom the central...

Glyceraldehyde has a one asymmetric carbon atom the central one and so two stereoisomers  which is also known as optical isomers are possible, which is two forms of glyceraldehyde,

Why tpp and ttp are vital for the nerves and cardiac tissues, Why TPP and T...

Why TPP and TTP are vital for the nerves and cardiac tissues? TPP and TTP are interconvertible and arc involved in carbohydrate metabolism. As discussed above, when there is in

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