Anatomy: Animals Inside

Tissue and Cells

How often is the epithelium replaced?

Epithelial cells are constantly being replaced and regenerated during an animal’s lifetime, which is why some people say in jest, “As humans, we become a ‘different person’ every so often.” For example, the epidermis (outer layer of the skin) is renewed every two weeks; the epithelial lining of the stomach is replaced every two to three days; and the liver, a gland consisting of epithelial tissues, easily regenerates after portions are removed surgically.


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