The midpiece of spermatzoa in nearly all vertebrates is enclosed in a sheath of mitochondria, which provide a ready source of ATP necessary for sperm motility. Here, a longitudinal section through sp...

Figure 428 from Chapter 16 (Cytoplasmic matrix and cytoskeleton) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. Papillary muscle of cat heart shows one sarcomere length of two adjacent myofibrils at h...

A longitudinal section of somatic cilia of Coleps showing the axoneme, basal body, and attached fibrous and microtubular elements. Adjacent digestive vacuoles and cortical cytoplasm evident with typic...

Figures 193 (upper) and 194 (lower) from Chapter 5 (Endoplasmic Reticulum) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. In this fast acting muscle of the toadfish swim bladder, multiple layers of sa...

Nuclear envelope and spindle dynamics when the nucleus moves into the neck of kar9delta Nip100deltaCAP-Gly double mutant cells arrested in S phase. In these cells, the spindle failed to enter the bud ...

Transmission electron micrograph of a pancreatic acinar cell from the bat Myotis lucifugus showing the 'classic' ultrastructural features of the nucleus after glutaraldehyde fixation. The large darkly...

Figure 430 from Chapter 16 (Cytoplasmic matrix and cytoskeleton) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. Flight muscle of the Drosophila melanogaster. Compared to striated muscle of vertebrate...

Transmission electron micrograph of Leydig cell nucleus from the domestic boar contains a region (arrow) thought to represent the single X chromosome which is largely heterochromatic. The chromosome i...

Transmission electron micrograph showing the extensive accumulation of darkly stained heterochromatin at the nuclear periphery typical of many differentiated cells. Heterochromatin is excluded from re...

Free microtubule sliding in nip100deltaCAP-Gly cnm67delta double mutant cells. Movie plays at 50x real time and is movie S12. Compare with movie S11 (CIL# 23601). Data analysis for movies S11 and S12 ...