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

Define transport and uptake of zinc by cells, Define Transport and uptake o...

Define Transport and uptake of Zinc by Cells? After absorption, zinc is bound to albumin and transported to the liver. In liver, it is concentrated and then transported to diff

Define age as a determinants of nutrient requirements, Define Age as a dete...

Define Age as a determinants of nutrient requirements? Age: Requirements change with increasing age between birth and maturity. Nutrient requirements per unit body weight are h

What is oogenesis , What is Oogenesis ? The female sex cells, or eggs,...

What is Oogenesis ? The female sex cells, or eggs, are formed in the ovaries, the primary sex organs of the female. The precursor of the egg cells, or oogonia, are formed duri

How does biological diversity relate to the characteristics, How does biolo...

How does biological diversity relate to the characteristics of the abiotic factors of an ecosystem? The availability of abiotic factors as light, moisture, mineral salts, heat

Show the parameters which are of interest in chd, Q. Show the parameters wh...

Q. Show the parameters which are of interest in CHD? Total Cholesterol: Serum totnl cholesterol equals the sum of HDL-cholesterol (HDL-c), VLDL-cholesterol (VLDL-c) and LDL-cho

Soil water-physical properties of soil, Soil Water Soil water relations...

Soil Water Soil water relationship is very important. In the fist place the supply of large quantities of water is necessary to satisfy the evapo-transpiration requirements of

Concept of species, Many definitions of species have been offered, but none...

Many definitions of species have been offered, but none of them proved to be satisfactory. The definitions did not categorically provide the basis to decide whether two similar gro

Define type of instruments used in spectral techniques, Define Type of Inst...

Define Type of Instruments used in Spectral Techniques? A wide range of instruments are available, possessing a combination of features but there is no rigid classification of

Pulmonary regurgitation, Pulmonary Regurgitation :  Most of the clinical c...

Pulmonary Regurgitation :  Most of the clinical cases are after balloon valvotomy or surgical valvotomy using a trans annular patch. It can be quantified by Echocardiography and D

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