Cell type
As cell type cells are summarized in biology, which exert a specific function within the organism.
Due to their function, they often have a corresponding shape of this function. Various cell types exist especially in multicellular organisms. Cells of the same cell type or different, that are closely related functional cell types that form a tissue, and various tissues that support each other in their function, form an organ. When a cell of a cell type goes into a different, this is referred to as differentiation. This often changes the appearance. The genetic information, the genome, though remains unchanged in the majority of cases, however, the proteome and the epigenetic code change. During the development of multicellular creatures some differentiation steps are irreversible, so that a differentiated cell is not able to change in any other cells. This can only stem cell and meristem cells. Immortalized cell types referred to in the cell culture as the cell lines.
Differentiation of the cell types
The basic distinction is that between the Eucyte ( cell of eukaryotes and thus all higher organisms ) and the Protocyte ( cell of prokaryotes ). The names of the individual cell types have established themselves over time. When plant tissues are primarily distinguished and named most cell types after this, eg Parenchyma or epidermis cells.
Morphology
The simplest feature, to distinguish between different cell types, is the shape and size. A human ovum for example, has a diameter of about 0.1 mm, it is therefore just visible to the naked eye. It can, for example, two different types of fat cells are microscopically distinguished. The shape of fat cells in white adipose tissue differs significantly from the form of fat cells in brown adipose tissue. The form also provides a clear way to distinguish.
Coloring
Since differentiated cells perform different functions, the cell organelles in the different cell types are pronounced differently. A comparison, for example, red blood cells and nerve cells in the microscopic magnification shows that nerve cells in a special stain have a " grainy" appearance, but the red blood cells make up different dar.
Immunohistology
Certain cell types, for example, the immune system can not be based on the shape or chemical coloring distinguish. Here, a special type of coloring are applied by the different surface proteins are differentiated and classified. A division is for cluster of differentiation. As an example of the T - lymphocyte may be mentioned. One way immune cells according to their size and granularity as well as their surface molecules to distinguish is a measurement in the flow cytometer. The B- lymphocytes can be distinguished from its differentiated form of the plasma cells through the CD 20. CD 20 is expressed on the surface of B-lymphocytes. It is positive for all the B- lymphocytes, in the plasma cells, the detection of the CD 20 is always negative.
Examples of cell types in humans and animals
- B-lymphocyte
- Blastomere
- Ovum
- Erythrocyte
- Fibroblast
- Hepatocyte
- Myoblast
- Nerve cell
- Osteoblast
- Osteoclast
- Sperm
- Stem cell
- T- lymphocyte
- Zygote
Examples of plant cell types
- Meristemzelle
- Apical cell
- Parenchymal cell
- Sieve cell
- Sklerenchymfaser
- Stone cell
- Epidermal cell
- Guard cell