Centriol Dr.Jastrow's electron microscopic atlas

Vocabulary
of micros-
copic
anatomy
specialist terms
explained in
English +
German

Every attempt was made to provide correct information and labelling, however any liability for eventual errors or incompleteness is rejected!

dieser Seite

Editor:
Dr. med.
H. Jastrow

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Overview centriols (Centriolae):
Pages with explanations are linked to the text below the images if available! (Labelling is in German)


Pair of centriols in a pinealocyte (rat)	Centriol of a lymphocyte (rat)	Centriol in longitudinal section (rat)	Overview of this picture	Stereo image of a cross-sectioned atypi- cal centriol of a cell of the Limbus spiralis (rat)


Centriol cross-section (rat) 1	Centriol cross-section (rat) 2	Centriol cross-section (rat) 3	Centriol longitudinal (Fibrocyte, rat)	Centriol (rat)	Diplosome in the cytoplasm of a fibrocyte (rat)


mt originating for a cen- trosome in mitosis (rat)	overview therof with more spindle fibres thymus (rat)

Central bodies or centriols (Terminologia histologica: Centriolae) are electron-dense tubules with diameters of ~ 150 nm and a length of 300 - 500 nm. They consist of 9 tripletts of microtubules interconnected via fine filaments. The tripletts are not at right angle to the axis of the centiole but diverge by about 30 degrees from it. The tripletts are formed of an inner, complete and round A-tubule with 13 protofilaments, an attached incomplete B-tubule with 10 protofilaments, and an outer C-tubule, which is also incomplete with 10 protofilaments. The protofilaments are helical tubules with alternating alpha- and beta-tubulin layers. There are two short proteins attached to the inner (A-)tubule of which one connects the A-tubule to the next triplett and the other points towards the centre of the centriole. The pericentriolar matrix surrounding the centrioles contains gamma-tubulin and pericentrin. It serves for attachment of further outer microtubules of the cytoskeleton.
Human cells usually possess two centrioles which are at right angle to each other in close vicinity, therefore this pair of centrioles is called diplosome. The diplosome and the surrounding pericentriolar matrix are summarised as centrosom or cytocentre.
In most cases centrioles are present close to the nucleus or nearby golgi-apparatuses.
During mitosis the centrioles march on opposite poles of the cell after doubling at the end of the S-phase or during the prophase. Hereby the new centrioles are formed at right angle to the former ones. Spindle fibres, which are microtubules span across the cell during metaphasis of the mitosis for binding and correct splitting of chromosomes. Thus centrioles are organisers of the chromatin and, further, are involved in synthesis of the nuclear membrane during mitosis.
Centrioles are structurally identical to basal bodies of kinocilia to which, of course, they are not connected.

--> microtubuli, basal bodies of kinocilia, mitosis
--> Electron microscopic atlas Overview
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