What Is the Function of Epithelial Tissue?

Epithelial tissue is composed of a large number of cells and a small amount of interstitial cells. The shape of the cells is relatively regular and there are few interstitial cells.

Epithelial tissue

Epithelial tissue is composed of a large number of cells and a small amount of interstitial cells. The shape of the cells is relatively regular and there are few interstitial cells.

The characteristics of epithelial tissue are: there are many cells and less interstitial; epithelial cells have two polarities, one pole is called the free surface, facing the body surface or the cavity surface of the cavity organ, and the other pole is called the basal surface, facing the deep Connective tissue; connecting surfaces between epithelial cells are lateral. Most of the epithelial tissues have no blood vessels, and the required nutrients depend on the interstitial fluid in the connective tissue to penetrate into the epithelial cell space through the basement membrane. Epithelial tissue is usually rich in nerve endings and can be exposed to various stimuli. ^[1]

General structural characteristics

Epithelial tissue has strong regeneration capacity. There are two kinds of regeneration with different properties, namely physiological regeneration and pathological regeneration.

Under certain physiological or pathological conditions, the metaplasia of epithelial tissue has differentiated and matured tissues, and its constituent cells can adapt to the changed conditions. The morphology, arrangement, and function of the cells have changed, which is commonly referred to as tissue metaplasia or mutation. The metaplasia of epithelial tissue is more obvious. For example, long-term smokers or patients with chronic bronchitis, the pseudostratified ciliated columnar epithelium of the trachea can become a stratified flat epithelium; the transitional epithelium of the kidney stone site can be transformed into a stratum corneum due to stimulation and friction Flat epithelium.