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CIL:11602*  Cite 

Figs. 315 from Don Fawcett's Chapter 12 (Centrioles). The dense material that forms the capitulum and the cross-striated columns of the connecting piece in spermatozoa is formed in intimate association with the proximal and distal centrioles, respectively. These versatile organelles are believed to play a dominant role in the organization of these components of the spermatozoon. The cross-striated columns of the connecting piece are probably homologous to the cross-striated rootlets that often extend downward from the basal bodies into the cytoplasm of ciliated epithelial cells. Traditionally the basal bodies were regarded as kinetic centers responsible for initiating the beat of cilia and flagella. This interpretation is no longer tenable. It has been shown that sperm tail movements continue after laser microbeam destruction of the centriolar region. Moreover, electron microscopic studies of spermatogenesis have shown that the distal centriole which initiates development of the flagellum later disintegrates and is no longer present in the mature spermatozoon. The juxtanuclear centriole usually persists, occupying a niche just beneath the capitulum that attaches the tail to the sperm head. In some species, however, this centriole also disintegrates during sperm maturation. Thus centrioles are essential for development of cilia and flagella but are not required to initiate and maintain their beat. Observe in the accompanying micrograph that no distal centriole can be identified at the base of the axoneme. A copy of the chapter is available on the ASCB's BioEDUCATE website.

Biological Sources
NCBI Organism Classification
Cricetulus griseus
Cell Type
Cellular Component
Biological Context
Biological Process
spermatid development
Don W. Fawcett
D. M. Phillips
ISBN 0721635849
Anat. Rec. 165:153-184, 1969
Digital Object Identifier (DOI)
Archival Resource Key (ARK)
Grouping This image is part of a group.
Image Type
transmission electron microscopy (TEM)
illumination by electrons
Image Mode
detection of electrons
Parameters Imaged
electron density
Source of Contrast
stain with broad specificity
Visualization Methods
stain with broad specificity
osmium tetroxide
uranyl salt
lead salt
Processing History
recorded image
Print from negative scanned for Photoshop.
Data Qualifiers
processed data
Spatial Axis Image Size Pixel Size
X 910px ——
Y 930px ——