Neurites, Biology

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.
Posted Date: 10/1/2012 4:15:30 AM | Location : United States







Related Discussions:- Neurites, Assignment Help, Ask Question on Neurites, Get Answer, Expert's Help, Neurites Discussions

Write discussion on Neurites
Your posts are moderated
Related Questions
hi there,i would like u to help me with understanding Hutchinson phyletic dieta

does jellyfish depend on solarenergy

DIGESTIVE  SYSTEM OF MAMMALS The tube from mouth up to anus is called alimentary canal. Alimentary canal of man is about 9 meter and rabbit is about 6 meter. Digestive

Importance of Forests - Habitat and Food Forests provide habitat, and food as well as protection to wildlife species against extremes of climate and help in balancing carbon d

Where are the openings into the coronary arteries? Why is this important when blood is flowing?

why is it known as middle man

List of Conditions Requiring Rapid Treatment of Hypertension 1) Cardiac: • Acute aortic dissection • Acute left ventricular failure • Acute or evolving myocardial i

Unfortunately, unlike heart failure due to systolic dysfunction, diastolic heart failure has been studied in few clinical trials, so there is little evidence to guide the care of p

MEIOSIS Every  organism is mortal, It  becomes  old and wornout  with advancing age  (= ageing )  and ultimately dies ,Before  death   however  ,it reproduces its own  kind, so

Induction of Defensive Barriers in Plants Several polymers deposited near surface of plants form an effective barrier against invasion or stress. Cuticle (which consists of a