1, adhesion-dependent cells
Adherence is the basic way for the survival, growth and development of biological cells in vivo, including two ways: cell-to-cell contact and cell-to-cell contact with extracellular matrix. It is based on the characteristics of cell adherent growth, which makes different cells combine to form tissues and keep in touch with the surrounding environment. Therefore, most cells of organisms must be attached to solid supports to grow. In vitro culture, most cells still maintain this characteristic, that is, they must be attached to supports such as culture bottle walls to grow. According to the morphology of cells cultured in vitro attached to the support, they can be roughly divided into four types:
1) Epithelial cells are flat, irregular and polygonal, with nuclei in the middle, closely connected with each other and growing in a single layer. Cells derived from ectoderm and endoderm, such as digestive tract epithelium, liver, pancreas and alveolar epithelium, are mostly epithelial cells when cultured and grown in vitro.
2) Fibroblasts are spindle-shaped or irregular triangles after adhering to the wall, with prominent cytoplasm and 2-3 protrusions of different lengths. Cells derived from mesoderm, such as cardiac muscle, smooth muscle and vascular endothelial cells, are usually fibroblast-like in vitro culture.
3) The wandering cytoplasm often protrudes from the pseudopoda or protuberance, showing active wandering or deformation movement, adhering to the support and growing scattered, generally not connected into pieces.