Parênima

Parênima is the functional tissue of an organ, consisting of the cells that perform its specialized activities. In both botany and anatomy, the term distinguishes the active, functional tissue from the surrounding supportive framework, known as the stroma. Parênima can therefore refer to plant tissues as well as the functional tissue of animal organs.

In plants, parênima (parenchyma) is the most common type of ground tissue. It is typically made up of living cells with thin, flexible primary walls, usually isodiametric in shape and possessing large central vacuoles. Parênima cells remain metabolically active and capable of division, which supports growth, wound repair, and regeneration. Functions are diverse: photosynthesis in chlorenchyma; storage of carbohydrates, oils, and other substances in storage parênima; secretion and transport; and, in aquatic or marsh plants, specialized forms such as aerenchyma, which contains large air spaces to aid buoyancy and gas exchange. Parênima forms much of the mesophyll in leaves and the cortex and pith in stems and roots.

In animals and humans, parênima refers to the functional tissue of an organ, as opposed to its stroma (the supportive framework, including connective tissue, blood vessels, and nerves). Examples include hepatic parênima (hepatocytes that perform liver metabolism), cerebral parênima (neurons and supporting glial cells), and pulmonary parênima (alveolar tissue involved in gas exchange). The condition of the parênima is a key determinant of organ function and disease progression, with injury or degeneration typically affecting the organ’s functional cells.