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

Differentiate blood retinal barrier and aqueous barrier, What are the diffe...

What are the differences between blood retinal barrier and blood aqueous barrier? Blood Retinal Barrier: Blood retinal barrier is present in retina. In retina there are t

Find the electric potential, (a) Find the electric potential, taking zero a...

(a) Find the electric potential, taking zero at infinity, at the upper right corner (the corner without a charge) of the rectangle in the figure. (Let y = 3.7 cm and x = 6.7 cm.)

Explain carbon and oxygen aspect of using phase rule, Explain carbon and ox...

Explain carbon and oxygen aspect of using phase rule? Consider a system containing solid carbon (graphite) and a gaseous mixture of O 2 , CO, and CO 2 . There are four species

Define the herbals, Q. Define the Herbals? During the Middle Ages, foll...

Q. Define the Herbals? During the Middle Ages, following the decline of the Greek and Roman civilisations, little significant botanical progress was made. The early herbals (i.

Hemerythrins - respiratory pigments, Hemerythrins - Respiratory Pigments ...

Hemerythrins - Respiratory Pigments The Hemerythrins are rather rare. They take place in some animals belonging to the minor phyla like the sipunculid worms, some brachiopods,

Create a punnett square, Q. Assume the gene for dimples, d, is recessive. T...

Q. Assume the gene for dimples, d, is recessive. Then assume that two individuals with the genotypes Dd and dd mate. Create a Punnett square for this mating and state the probabili

Classic procedure- mitral valve replacement, Classic Procedure: The app...

Classic Procedure: The approach is the same as described earlier for open mitral valvotomy. The excision starts with an anterior incision on the anterior leaflet at 12o'clock p

Systmetic, Relation between taxonomy and ecology

Relation between taxonomy and ecology

Define conjugation in brief, Define Conjugation in brief. A form of se...

Define Conjugation in brief. A form of sexual reproduction in ciliates (Ciliophora). During conjugation two ciliate protozoans join and macronuclei disappears. After meiotic d

Explain amylose, Amylose Amylose molecules have molecular weights rangi...

Amylose Amylose molecules have molecular weights ranging from 10 4 -20 6 . Amylose can form an extended shape (hydrodynamic radius 7-22 nm) but generally tends to wind up into

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