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Crenation (from modern Latincrenatus meaning "scalloped or notched", from popular Latincrena meaning "notch")[1] in botany and zoology, describes an object's shape, especially a leaf or shell, as being round-toothed or having a scalloped edge.[1]
The descriptor can apply to objects of different types, including cells, where one mechanism of crenation is the contraction of a cell after exposure to ahypertonic solution, due to the loss of water throughosmosis.[2]: 229–230 In a hypertonic environment, the cell has a lower concentration ofsolutes than the surroundingextracellular fluid, andwaterdiffuses out of the cell by osmosis, causing thecytoplasm to decrease in volume. As a result, the cell shrinks and thecell membrane develops abnormal notchings.Pickling cucumbers andsalt-curing of meat are two practical applications of crenation.[2]: 229
Plasmolysis is the term which describes plant cells when the cytoplasm shrinks from the cell wall in a hypertonic environment. In plasmolysis, the cell wall stays intact, but the plasma membrane shrinks and the chloroplasts of the plant cell concentrate in the center of the cell.
Crenation is also used to describe a feature ofred blood cells. These erythrocytes look as if they have projections extending from a smaller central area, like a spiked ball. The crenations may be either large, irregular spicules ofacanthocytes, or smaller, more numerous, regularly irregular projections ofechinocytes.[3] Acanthocytes and echinocytes may arise from abnormalities of the cell membrane lipids or proteins, or from other disease processes, or as anex vivoartifact.