Parenchyma

Parenchyma is a term used to describe a bulk of a substance. It is used in different ways in animals and in plants.

The term is New Latin, f. Greek παρέγχυμα - parenkhuma, "visceral flesh", f. παρεγχεῖν - parenkhein, "to pour in" f. para-, "beside" + en-, "in" + khein, "to pour".

In animals

The parenchyma are the functional parts of an organ in the body. This is in contrast to the stroma, which refers to the structural tissue of organs, namely, the connective tissues.

In cancer, the parenchyma refers to the actual mutant cells of a single lineage, whereas the stroma is the surrounding connective tissue and associated cells that support it.

Early in development the mammalian embryo has three distinct layers: ectoderm (external layer), endoderm (internal layer) and in between those two layers the middle layer or mesoderm. The parenchyma of most organs is of ectodermal (brain, skin) or endodermal origin (lungs, gastrointestinal tract, liver, pancreas). The parenchyma of a few organs (spleen, kidneys, heart) is of mesodermal origin. The stroma of all organs is of mesodermal origin.

Examples include:

In plants

Parenchyma cells are thin-walled cells of the ground tissue that make up the bulk of most nonwoody structures, yet sometimes their cell walls can be lignified. Parenchyma cells in between the epidermis and pericycle in a root or shoot constitute the cortex, and are used for storage of food. Parenchyma cells within the center of the root or shoot constitute the pith. Parenchyma cells in the ovary constitutes the nucellus and are brick-like in formation. Parenchyma cells in the leaf constitute the mesophyll; they are responsible for photosynthesis and they allow for the interchange of gases.

Translation

The word "Parenchyma" occurs as such in the following languages: English, Polish.

Translation(s) in other languages: Arabic: متن, Catalan: Cèl·lules parenquimàtiques, German: Parenchym, Estonian: Põhikude, Spanish: Parénquima, Esperanto: Parenkimo, Basque: Parenkima, French: Parenchyme#Biologie_v.C3.A9g.C3.A9tale, Italian: Parenchima, Hungarian: Parenchima, Dutch: Parenchym, Japanese: 柔組織, Portuguese: Parênquima, Russian: Паренхима, Serbian: Паренхимска ткива.