Polygonal, oval-shaped nucleus, located in the center of the cell; adjacent cells are jagged.

Polygonal, round core, centered, secretion and absorption

Goblet cells (with striated borders, good for intestinal absorption)

columnar (most, with numerous cilia on the free surface), spindle, cone, and goblet cells The positions of the nuclei are not at the same level, but the bases are all attached to the basement membrane

Basal cells are short columnar and are stem cells with the ability to proliferate and differentiate. The flat cells on the outermost layer gradually fall off

surface cells, cover cells middle layer cells basal cells

Secretory part: often called acini, composed of a single layer of glandular cells with a lumen in the center

Ducts: composed of single or stratified epithelium, some can also secrete or absorb water and electrolytes

The top of the side of cells; more common in single column, single epithelium

On the top of the epithelial cells; there are filaments outside the cytoplasm, and there are thin layers of dense material and microfilaments in the cytoplasm, which form the terminal network (microvilli).

Cadherin, anchoring protein, keratin filaments; developed in stratified squamous epithelium of skin susceptible to friction, esophagus, etc.

The intercellular space is very narrow, and the columnar protein is called a connectosome (6 rod-shaped subunits); electrical impulses can be transmitted between cardiomyocytes, smooth muscle cells, and nerve cells; chemical information can be transmitted through this

Placode: secreted by epithelial cells

Reticular plate: secreted by fibroblasts of connective tissue