BIOL 1215 Lecture Notes - Cell Nucleus, Osmosis, Microvillus
Document Summary
Cells in layers and cell shapes: arrangement of cells in layers- Cells arranging in one or more layers depending on function: simple epithelium- Single layer of cells that function in diffusion, osmosis, filtration, secretion (mucus, sweat, enzymes), or absorption (fluid from digested food): pseudostratified epithelium- Appear to have multiple layers because cell nuclei lie at different levels and not all cells do not reach apical surface. Cells that do extend to apical surface may contain cilia. Cells that do not extend to apical surface (goblet cells) secrete mucus: stratified epithelium- Consist of two or more layers of cells that protect underlying tissues in areas of wear and tear: cell shapes- Cells vary in shape depending on their function: squamous- Arranged like floor tiles and are thin, which allows for rapid passage of substances: cuboidal- As tall as they are wide, shaped like cubes or hexagons. May have microvilli at apical surface and function in secretion or absorption: columnar-
