1. The central structure of the principal piece is axoneme.

2. The early axoneme of a basal body-axoneme complex consists nine doublets with only inner and outer dynein arms, no central microtubules.

3. Cilia are located on almost all cell types of the human body, the basic structure includes a microtubule cytoskeleton, the axoneme, and the surrounding ciliary membrane.

4. The distal centriole is like a bell, with its top connecting to the proximal centriole and with the entrance of its bottom connecting to the axoneme of the sperm tail.

5. The organelles in un - conglutinated sperms arranged dispersedly, mitochondrial derivatives and alongboth sides of axoneme deformed.