Difference between revisions of "2017 Group Project 6"

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=Basic anatomy of the Cerebellum=
 
=Basic anatomy of the Cerebellum=
 
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum <ref><pubmed>25336734</pubmed></ref>]]
 
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum <ref><pubmed>25336734</pubmed></ref>]]
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==Neural Development==  
 
==Neural Development==  

Revision as of 17:53, 14 September 2017

2017 Student Projects 
Student Projects: 1 Cerebral Cortex | 2 Kidney | 3 Heart | 4 Eye | 5 Lung | 6 Cerebellum
Student Page - here is the sample page I demonstrated with in the first labs.I remind all students that you have your own Group Forum on Moodle for your discussions, it is only accessible by members of your group.
Editing Links: Editing Basics | Images | Tables | Referencing | Journal Searches | Copyright | Font Colours | Virtual Slide Permalink | My Preferences | One Page Wiki Card | Printing | Movies | Language Translation | Student Movies | Using OpenOffice | Internet Browsers | Moodle | Navigation/Contribution | Term Link | Short URLs | 2018 Test Student

Introduction

Mark Hill (talk) 16:16, 14 September 2017 (AEST) OK Feedback

Basic anatomy of the Cerebellum

Structure of the Cerebellum [1]


Neural Development

(z5114433)

Diagram of a 2 Day Old Embryo[2]

Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum [3] . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as spina bifida and anencephaly can arise if the tubes do not close effectively.

Microanatomy

Cortical Layers

Purkinje/Pyramidal Cells

Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum. They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling. Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology. z5177699

Granule Cells

Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899. Cerebellar granule cells are the most numerous cell type in the human brain. They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells. Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum. https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31 z5177699

Deep Nuclei

There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei. The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells. The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm

Other Cells

Early Brain Structure

z5114433 - primary - secondary - ventricles

Metencephalon

z5113034

Blood Supply

z5113034

Meninges

(z5114433)

Cerebellum Development

(find images of the visualiation of the foetal cerebellum)

As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate [4] Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure.

The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter [5]. The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. The adjacent rhombic lips gives rise to cerebellar granule cells. [6]

z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 <ref name="PMID2775156">

Cerebellum Development Stages

z5114433

Embryonic Cerebellum Development

==Fetal Cerebellum Development

Third Trimester

Developmental signalling processes

- Mechanical Movement of Neurones from Metencephalon

- Number of Divisions Determines Cell Type

- Differentiation of Specific Neurones

Historic Images

Abnormal Development

z5018156

z5076158 could be a good article to use - https://www.ncbi.nlm.nih.gov/pubmed/22108217

References

  1. <pubmed>25336734</pubmed>
  2. https://www.ncbi.nlm.nih.gov/books/NBK26814/
  3. https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'
  4. <pubmed>7605067</pubmed>
  5. <pubmed>25336734</pubmed>
  6. Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.

https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9

Terms