Difference between revisions of "Neurogenesis - Anatomy & Physiology"

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==Neural Plate Induction==
 
==Neural Plate Induction==
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*Cells of the ectoderm are directed to develop into either neural ectoderm or epidermis.
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*How is this choice made?
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*Formation of the '''neural ectoderm''' is the default pathway.
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**Therefore, in order to make epidermis, a signal from the environment must be diverting cells from going down this default pathway.
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**This signal comes from the lateral plate mesoderm (LPM) which directs ectoderm to become epidermis.
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***The notochord (lying along the midline) secretes an antagonist to the factor of the LPM so that neural ectoderm is formed above the notochord.
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*Therefore, in lateral regions ectoderm becomes epidermis and along the midline ectoderm becomes neural ectoderm.
  
 
==Primary Neuralation==
 
==Primary Neuralation==
  
 
==Secondary Neuralation==
 
==Secondary Neuralation==

Revision as of 13:32, 26 August 2008

BACK TO DEVELOPMENTAL BIOLOGY

Introduction

The nervous system develops from ectoderm. Some of the ectoderm will also develop into the epidermis. Signalling factors from elsewhere in the embryo determine which parts of the ectoderm become neural tissue or epidermis.

In the anterior part of the embryo the ectoderm forms the neural plate, a flat layer of ectodermal cells lying directly above the node. The process of development from this neural plate to the nervous system is split into two parts; primary and secondary neuralation.

Neural Plate Induction

  • Cells of the ectoderm are directed to develop into either neural ectoderm or epidermis.
  • How is this choice made?
  • Formation of the neural ectoderm is the default pathway.
    • Therefore, in order to make epidermis, a signal from the environment must be diverting cells from going down this default pathway.
    • This signal comes from the lateral plate mesoderm (LPM) which directs ectoderm to become epidermis.
      • The notochord (lying along the midline) secretes an antagonist to the factor of the LPM so that neural ectoderm is formed above the notochord.
  • Therefore, in lateral regions ectoderm becomes epidermis and along the midline ectoderm becomes neural ectoderm.

Primary Neuralation

Secondary Neuralation