The cortex of Paramecium consists of a plasma membrane and alveolar sacs, with their inner and outer alveolar membranes that limit the area in which endocytosis can easily occur to only the parasomal ...

A high resolution image of the pellicle of Opercularia coarctata. Indentations of the plasma membrane penetrate the alveolar membranes end as coated pits. These pits are also known as pellicular pores...

This electron micrograph shows the plasma membrane of epithelial cells of the brush border of the cat intestine, obtained from a thin section parallel to the free surface. The ability to visualize ce...

In quick-freeze deep-etch preparations in which cells are slam frozen the pellicle and the plasma membrane tends to be flattened. The double rings are present but only the outer ring of IMPs stand out...

This freeze fracture view of the pellicle of V. microstoma near the aboral end of the zooid shows the region where the width of each circumferential alveolus is narrower and thus the strings of fractu...

This image, produced by the freeze-fracture technique, shows regional specialization in the structure of mammalian sperm. The P-face of the plasma membrane of a guinea pig sperm tail can be divided i...

The E-fracture faces of the plasma membrane and cytopharyngeal membranes are continuous but differ in appearance since the cytopharyngeal membrane is studded with IMPs while the plasma membrane has fe...

In quick-freeze deep-etch preparations the plasma membrane can be seen to contain plaques or plates of intramembrane particles (IMPs) that are regularly aligned in rows with a center-to-center spacing...

In quick-freeze deep-etch preparations the plasma membrane can be seen to contain plaques or plates of intramembrane particles (IMPs) that are regularly aligned in rows with a center-to-center spacing...

Freeze fracture of the plasma membrane and outer alveolar membrane of the pellicle of V. microstoma. The surface of Vorticella is encircled by rings which follow the septa of underlying alveoli. In th...