Gallery of Sperm Images and Videos:

This gallery of images and movies illustrates the anatomy of spermatozoa from the nematode C. elegans, including their final maturation steps and their motility as functioning sperm. All images are the work of Sam Ward (U. Arizona, retired), Paul Muhlrad (U. Arizona, formerly) and Craig LaMunyon (Cal Poly, Pomona, California).

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Spermatozoon SEM
This is a mature sperm cell, or spermatozoon, from C. elegans. At the right is the pseudopod, which the cell uses for crawling. The pseudopod has knobby projections, called vilipodia, which constantly flow rearward toward the cell body.
Here are four C. elegans spermatozoa. The one at left center has just started to form its pseudopod.
Spermatozoon TEM
This is a cross section through a mature sperm cell, or spermatozoon, from C. elegans. At the right is the pseudopod, which the cell uses to crawl and at the left is the cell body, which contains the nucleus (dark spot at the center), mitochondria, and unusual organelles called membranous organelles.
This is a picture of undifferentiated sperm cells, or spermatids, from C. elegans. Note that the cells are symmetrical, not yet having formed their pseudopod.
Scanning EM images showing the process of spermiogenesis, sperm cell differenetiation.
Budding spermatids SEM
This scanning electron micrograph shows four haploid spermatids forming as products of the final cell division in spermatogenesis.
Mutant spermatozoa
This set of SEM panels shows examples of sperm from some of the different sperm mutants. For comparison, a normal sperm is shown at the top left.
Crawling sperm
Video shows C. elegans sperm crawling via its pseudopod. Note that the pseudopod, on the right, moves forward bringing the cell body of the sperm with it.
Many crawling sperm
Video shows many C. elegans sperm crawling around.
Treadmilling sperm
Video shows how unlike most sperm cells, which swim with a flagellum, nematode sperm crawl with a pseudopod.
Video shows spermatids undergoing spermiogenesis on a microscope slide in response to a chemical that was added to them.
 Dividing spermatocytes
Video shows two secondary spermatocytes video undergo the second meiotic division to form four haploid (i.e. having only one copy of each chromosome) spermatids.