parenkyymiin

Parenkymiin, or parenchyma, is a term used in biology to describe the functional tissue of an organ or organism, as opposed to supportive or connective tissues. The concept appears in both botany and anatomy, where it refers to the living, metabolically active cells that carry out the primary activities of the tissue.

In plants, parenchyma is the most common type of ground tissue and serves multiple roles. Parenchyma cells typically have thin primary cell walls, are alive at maturity, and can divide or dedifferentiate in response to damage. They form the bulk of most soft plant organs and are involved in photosynthesis (chlorenchyma), storage of starch, oils, and water, and wound repair. Specialized parenchyma subtypes include chlorenchyma, which contains chloroplasts for photosynthesis; storage parenchyma, which stores nutrients; and aerenchyma, which contains large air spaces to aid buoyancy and gas exchange in aquatic plants.

In animals and humans, parenchyma refers to the functional tissue of an organ, consisting of the cells that perform its specific tasks, as opposed to the stroma, which provides structural support. Examples include hepatic parenchyma (liver cells, hepatocytes) and renal parenchyma (functional kidney tissue). The term is also used in pathology to describe the tumor’s functional cells, distinguishing them from the surrounding connective or supportive framework.

Etymology traces parenchyma to Greek roots meaning “beside” or “alongside” the stroma, reflecting its role as the primary functional component of tissues and organs.