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

Explain metabolic response to injury, Explain Metabolic Response to Injury?...

Explain Metabolic Response to Injury? There is an increase in the basal metabolic rate above the normal. The degree of hyper metabolism is related to the severity of the injury

Explain hydrolyases, Hydrolyases These enzymes (code EC 3) catalyze th...

Hydrolyases These enzymes (code EC 3) catalyze the hydrolytic cleavage of C-O, C-N, C-C and some other bonds, including phosphoric anhydride bonds.  Their trivial names  are f

Clothes , Clothes : The concept of clothes might have started even befo...

Clothes : The concept of clothes might have started even before weaving, as an extension of  the practice of carrying food hd  implements about.  Attachments with a convenient

Explain the procedure estimation of the amount of bacteria, Explain the Pro...

Explain the Procedure Estimation of the Amount of Bacteria? Now carry out the exercise following the steps enumerated herewith. 1. Prepare ten fold dilutions of E. coli cult

Valves of the heart, Pulmonary valve is surface marked at the sternal end o...

Pulmonary valve is surface marked at the sternal end of the left 3rd costal cartilage. Aortic valve is surface marked at the sternal margin of the left 3rd intercostal space. Mitra

What is a genotype, What is a genotype? What is the difference between geno...

What is a genotype? What is the difference between genotype and phenotype? Genotype is the genes, DNA nucleotide sequences have in the chromosomes of an individual that conditi

Design of expression vectors in transgenic animals, D esig n of expressio...

D esig n of expression vectors Expressing a transgene in an appropriate manner is a huge task. The gene construct that is quite active in transfected cells may be only weakl

Diabetes mellitus management after open heart surgery, Diabetes Mellitus Ma...

Diabetes Mellitus Management after Open Heart Surgery :  Diabetic patients undergoing coronary artery bypass surgery who are on oral hypoglycemic drugs are pre operatively s

Explain management strategies for genetically modified crops, Explain Manag...

Explain Management strategies for genetically modified crops? Crops that have been genetically modified (GM) to be toxic to insect pests are now common in US agriculture. Make

Explain difficult feeding and poor growth, Explain Difficult Feeding and Po...

Explain Difficult Feeding and Poor Growth to recognition of congenital heart disease? Difficult Feeding and Poor Growth: The parent of an infant with CHD may complain that the

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