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

Regulation of alkalinity and acidity of the plasma, Q. In which nephron por...

Q. In which nephron portion does the regulation of alkalinity and acidity of the plasma occur? The regulation of the acid-basic equilibrium of the body is done by the kidneys a

List some points to keep in mind while counselling, Q. List some points to ...

Q. List some points to keep in mind while counselling? 1. Judgment Do not be judgemental. Be a patient listener. Assess and make decision. 2. Patience and Acceptance

Is there vaccine against tuberculosis, Is there vaccine against tuberculosi...

Is there vaccine against tuberculosis? The vaccine against tuberculosis is known as BCG (bacillus Calmette-Guérin). BCG is not used in some countries where tuberculosis is not

How many different molecules composed, How many different molecules compose...

How many different molecules composed of (A) two (B) three, and (C) four amino acids, linked together by peptide bonds, can be made from the set of 20 naturally occurring amino aci

How does the synthetic theory of evolution explain this fact, In hospitals ...

In hospitals where many tuberculosis patients are treated the population of the tuberculosis mycobacteria may be constituted of multiresistant (to antibiotics) strains. How does th

Receptors - ear, EA R It is phono receptor as respond to sound...

EA R It is phono receptor as respond to sound waves. It is teloreceptor as receive stimuli from far distance. It is stato-acousting organ as concerned with b

Can you illustrate period of meiosis, Q. What is the crossing over? And In ...

Q. What is the crossing over? And In which period of meiosis does this event occur? Crossing over is the eventual exchange of chromosomal fragments among homologous chromosomes

Explain the function of the pupil and of the iris, Q. What is the function ...

Q. What is the function of the pupil and of the iris? The iris works like the diaphragm of a photographic camera since it has muscles that relax or contract varying the pupil d

Identify by mean of biochemical tests, The human blood group, related to th...

The human blood group, related to the MN system is controlled by two alleles, S and s. Three distinct phenotypes can be identified by mean of biochemical tests. Among 1000 Britishe

Excretion, Excretory organ for protozoa

Excretory organ for 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