bench definition, bench meaning | English dictionary. bench. n an apparatus for experimentation in optics, typically consisting of an adjustable arrangement of light source, lenses, prisms, etc. bench.
3 Principal characteristics of cells that make up epithelium. -Cells are closely apposed-they adhere to one another via specialized cell junctions-Exhibit both structural and functional polarity-Epithelium creates a selective barrier between the external environment and the underlying connective tissue.î î î.Cells are closely apposed-they adhere to one another via specialized cell junctions-Exhibit both structural and functional polarity-Epithelium creates a selective barrier between the external environment and the underlying connective tissue. î î î.
The lumen of the trachea is lined by pseudostratified columnar epithelium. Note that all the surface cells have cilia at their free (apical) surface. (What function do these cilia serve in the trachea?) Mucus-secreting unicellular gland cells (goblet cells) are interspersed among the ciliated cells.owever, observation of cells separated by teasing shows that all of the cells are attached to the underlying basement membrane, but only some reach the free surface of the epithelium. This kind of epithelium is most commonly found lining the passages of the respiratory system (e.g., trachea and bronchi).