Alternate header for print version

This image is copyright protected. Any public or private use of this image is subject to prevailing copyright laws. Please contact the content provider of this image for permission requests.
*CIL – Cell Image Library accession number. Please use this to reference an image.

CIL:11567*  Cite 

Figs. 311 & 312 from Don Fawcett's Chapter 12 (Centrioles). In ciliogenesis, newly formed single centrioles, serving as basal bodies, are arranged in rows and oriented perpendicular to the cell surface. The end that is adjacent to the membrane functions as a site of nucleation for microtubule protein which polymerizes on subunits a and b of the triplets to form the nine doublet microtubules of the axoneme. The centrioles arrive at the cell apex at different times and the polymerization of tubulin evidently begins as soon as the end of the organelle is juxtaposed to the membrane. Thus in the accompanying micrograph four developing cilia are seen in successive stages of growth. Flagella usually arise from one member of a pair of centrioles positioned at right angles. The axoneme grows out from the one perpendicular to the membrane. The lower figure on the facing page shows early stages in formation of a sperm flagellum. The differing lengths of the distal centrioles illustrated is attributable to the fact that the micrographs are not all from the same species. In one example (B) the second centriole is out of the plane of section. In sperm tail development the centrioles are involved in organizing other components in addition to the axoneme. In the most advanced stage shown (D), both centrioles are sectioned longitudinally. The thin line above the proximal centriole (*) is the anlage of the capitulum which will later articulate with the implantation fossa of the sperm nucleus. The periodic densities in the bracket (**) represent an early stage in assembly of the cross-striated columns of the connecting piece. The adjunct has begun to develop at the other end of the proximal centriole (at arrow). The centrioles thus appear to be involved in the organization of four distinct structures - axoneme, capitulum, centriolar adjunct, and connecting piece. A copy of the chapter is available on the ASCB's BioEDUCATE website.

Biological Sources
NCBI Organism Classification
Cell Type
ciliated epithelial cell
Cellular Component
Biological Context
Biological Process
cilium assembly
cilium axoneme assembly
Don W. Fawcett
Everett Anderson
ISBN 0721635849
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 922px ——
Y 1292px ——