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

Diplotene and diakinesis, Diplotene: The paired chromosomes repel eac...

Diplotene: The paired chromosomes repel each other and begin to separate. Separation however, is not completed, because homologous chromosomes remain united by their point

State the term in broad - lunule, State the term in broad - Lunule. In ...

State the term in broad - Lunule. In sand dollars, notches or holes which pass through the body of the animal. Their function is not fully understood though may be involved in

Regulation of the renal function, Q. Which are the three hormones that part...

Q. Which are the three hormones that participate in the regulation of the renal function? Antidiuretic hormone or ADH or vasopressin, atrial natriuretic factor (or ANF) and ald

Respiration, #question.what are the organs of respiration in the lwer form ...

#question.what are the organs of respiration in the lwer form of animals .

Energy storage, Energy Storage As we said above, food intake and ener...

Energy Storage As we said above, food intake and energy expenditure for animals is approximately equal. If energy expenditure exceeds food intake, then the excess energy is t

Why fats have highest heat energy density, Why Fats have highest heat energ...

Why Fats have highest heat energy density? Fats have highest heat energy density of 9 Kcal/g. It is the major storage form of energy in body requiring least space and minimum w

How plant transporting substances through tissue, How plants solve the prob...

How plants solve the problem of transporting substances throughout their tissues? In the bryophytes the substance transport is done by the diffusion. In the tracheophytes (pter

Explain the criteria for assessment of folate status, Explain the Criteria ...

Explain the Criteria for Assessment of Folate Status Red cell folate, continues to be used as an important index of folate status. It is suggested that adequate folate status i

Carbohydrates requirement during diabetes, Q. Carbohydrates requirement dur...

Q. Carbohydrates requirement during diabetes? Carbohydrates: These to a large extent depend on the food habits. Complex carbohydrates with more fibre are recommended to simple

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