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

Excretory, what are the excretory organs protozoa

what are the excretory organs protozoa

Explain japanese encephalitis, Japanese encephalitis  Japanese encephal...

Japanese encephalitis  Japanese encephalitis is an uncommon but potentially fatal mosquito-borne viral disease that occurs in rural Asia, especially near pig farms and rice pad

What are the results of prosthetic valve endocarditis, What are the Results...

What are the Results of prosthetic valve endocarditis? The hospital mortality for valve replacement for endocarditis varies between 4- 30 per cent. Operative mortality is highe

Zoology, differences regarding Tiger Planaria and the Iridescent Phyllodoce...

differences regarding Tiger Planaria and the Iridescent Phyllodoce

Measurement of light intensity, Measurement of Light Intensity How do w...

Measurement of Light Intensity How do we measure the intensity of a source of light falling on a surface? You know that light spreads out uniformly in all directions from a sou

Mention the role o ribosome in peptide, Mention the role o ribosome's in pe...

Mention the role o ribosome's in peptide -bond formation .How does ATP facilitate it? a) Of springs derived by asexual reproduction are known as clones. Justify giving two R

What is the function of the immune system, What is the function of the immu...

What is the function of the immune system? The immune system performs exact defense against agents, the antigens, that are foreign or harmful to the body. Exogenous antigens

Genetic, what is tay-sachs diseases in human beings as mendal incomplete do...

what is tay-sachs diseases in human beings as mendal incomplete dominance f2 genration

Poultry and duck diseases-marek''s disease, Marek's disease Marek's dis...

Marek's disease Marek's disease is a lymphoproliferative disease of chicken, quails, bantams and other free-flying birds. It is caused by the Gallid Herpesvirus 2 of subfamily

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