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

What is soil fertility evaluation, Soil fertility evaluation  In order ...

Soil fertility evaluation  In order to maintain soil fertility, nutrients removed from the soil by crops must be restored by the application of manures and fertilizers.  The se

Why ammoniotelic excretion occur, Why after the passage of animals from the...

Why after the passage of animals from the aquatic to the terrestrial habitat does the abandonment of the ammoniotelic excretion occur? Ammonia is a highly toxic molecule if not

Complete metamorphosis, Complete Metamorphosis In all Endopterygota i...

Complete Metamorphosis In all Endopterygota insects, where wings and other structures develop internally, (in invaginate imaginal epidermal pockets) such as beetles, wasps, b

Tunnel subvalvar stenosis, Tunnel Subvalvar Stenosis :  This variety ...

Tunnel Subvalvar Stenosis :  This variety is less common and extends from sub aortic area for a variable length of 10-30 mms (tunnel stenosis). In the severe variety, the tun

Define relation between volatile substances and proteins, Interactions betw...

Interactions between Volatile Substances and Proteins               Flavour binding may involve adsorption at the surface of food or penetration to the food interiority by diffu

How many chromosomes in a mouse cell, Mice (Mus musculus) have 40 chromosom...

Mice (Mus musculus) have 40 chromosomes per diploid cell (2n=40). How many double- stranded DNA molecules, and how many chromosomes are there in a mouse cell that is in the G2 stag

Nutrient budgets - nutrient cycles, Nutrient Budgets - Nutrient Cycles ...

Nutrient Budgets - Nutrient Cycles Nutrients are constantly being added and removed by natural and artificial processes. The measure of the input and outflow of nutrients thro

Cnidaria and protozoan, What are the advancement of cnidaria over protozoa

What are the advancement of cnidaria over protozoa

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