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

Mechanism of regeneration, MECHANISM OF REGENERATION - T.H. morgan reco...

MECHANISM OF REGENERATION - T.H. morgan recognised 2 primary mechanisms - M o r ph o l axis Epim orphosis 1. Production of enti

Which nitrogen is found in nature, What is the most abundant form under whi...

What is the most abundant form under which nitrogen is found in nature? The most abundant nitrogen-containing molecule found in nature is molecular nitrogen (N2). The air is 80

Explain about the supply curve or supply schedule, Explain about the supply...

Explain about the supply curve or supply schedule. The supply curve or schedule shows the total quantity of a good or a service supplied within aggregate, by whole sellers or f

Homology, Homology  indicates similarity between the two different nucleoti...

Homology  indicates similarity between the two different nucleotide or the amino acid sequences, generally with potential evolutionary importance. It is probably better to use more

Contact osteogenesis, Contact Osteogenesis: In this the osteogenic cells at...

Contact Osteogenesis: In this the osteogenic cells attach to the implant surface and the new (de novo) bone is formed on the implant surface first. The developing bone matrix can d

How do populations of predators vary in predatism, How do populations of pr...

How do populations of predators and prey vary in predatism? Whenever a predator population enhances at the first moment the prey population tends to decrease. At a second momen

What is the meaning of accumulation, What is the meaning of accumulation ...

What is the meaning of accumulation The word "accumulation" is used in many of the definitions in the sense that th e horizon must have more of the material in question than i

How is the nervous system characterized, Q. How is the nervous system chara...

Q. How is the nervous system characterized in beings of the phylum Annelida? How can one compare cephalization in annelids to cephalization in platyhelminthes and nematodes? An

Prevention of malaria, Prevention of malaria No drug for malaria preven...

Prevention of malaria No drug for malaria prevention is 100% effective. Travelers to countries that have malaria should seek prompt medical attention for febrile illness wherea

What type of athlete, What type of athlete would have a above average react...

What type of athlete would have a above average reaction time please explain.

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