What is a simple tissue called?

Simple tissue is called a tissue composed of only one type of cell. This term primarily applies to plant biology, where simple tissues include parenchyma, collenchyma, and sclerenchyma, each performing specific functions.

Parenchyma consists of living cells with thin walls and serves multiple roles including photosynthesis, storage, and tissue repair. You find parenchyma in the fleshy parts of fruits, the middle layers of leaves, and throughout plant stems. Collenchyma contains living cells with unevenly thickened walls that provide flexible support to growing plant parts—it's common in leaf stalks and beneath stem epidermis, allowing plants to bend without breaking. Sclerenchyma comprises cells with thick, lignified walls that provide rigid support; many sclerenchyma cells are dead at maturity, their cell walls forming strong fibers and protective layers. In animal biology, the concept of simple tissue is less commonly used, though simple epithelium (a single layer of epithelial cells) represents an analogous concept—it forms linings where absorption, secretion, or filtration occurs, such as in the intestines, lungs, and blood vessels. Understanding simple tissues helps explain plant structure and function. When you bite into a crisp apple, you're experiencing parenchyma cells' turgidity. The stringy parts of celery contain collenchyma fibers. Hard nutshells consist largely of sclerenchyma. In gardening and agriculture, knowledge of simple tissues informs practices like pruning (which affects parenchyma regeneration) and crop selection based on desired tissue characteristics.