BIOL 207 Lecture Notes - Lecture 18: Epithelium, Basal Lamina, Mucous Membrane
• there are 2 categories of epithelium:
• Covering epithelium (ex. skin, lining of blood vessels, lining of heart chambers)
• glandular epithelium (salivary glands, digestive glands etc, that secrete material are the result of
epithelial cells that are designed to empty the substance into a glandular design and the glands release
the materials)
•
•
• epithelium cells have 2 surfaces (pg. 117)
• apical surface/end
• the end that faces upward and out. if the example is a lumen of your intestine, there are a lot of
columnar cells, whatever structure is facing the outside is the apical end
• basal surface/end
• the end that is near the bottom. the cells will attach to an underlying connective tissue
• basement membrane is at at the basal end of cell in a thin sliver of CT like material
• Basal Lamina; upper component. fixed to/attached to the basal end of the cell. synthesized,
manufactured by the epithelial cell itself. it is a pedestal that the cell adheres to. adheres to the cell
itself. it is called basal lamina because it is directly attached to the basal part of the cell.
• Reticular lamina; lower component. synthesized and made up by the connective tissue beneath
the epithelial cell.
• ** all epithelial cells have a thin sliver called the basement membrane, made up of 2 thin layers
within a thin layer. one produced by cell itself called basal lamina. under that is a thin layer produced by
the underlying connective tissue
Classification of epithelial (pgs 118-123/pg 119, figure 4.2)
• **oid- end
• 2 ways of classifying epithelium:
• Structural/cell shape
• Squamous epithelium (pavement); squamous means scale. these are flattened and thin cells.
they would be very good for diffusion across that cell, and transport across that cell. key places in body
that will be only 1 squamous cell thick.
• Cuboidal epithelium; have a cube shape, they are as wide as they are tall. more room for cellular
organelles. very good for secretion.
• Columnar epithelium; like a column, taller than they are wide. good for secretion because there
is a lot of room in the cell for structures involved with secretion. they are also adapted and designed for
absorption (materials coming in)
• Ciliated columnar cells; in respiratory tract, the trachea. Celia work in conjunction with secretion
in the trachea called mucous. when the Celia is moving in a superior direction, it is taking mucous with it,
small amounts, as the mucous is going up, the mucous traps foreign particles you don't want in lungs.
slowly the mucous goes up, and then travels back down the esophagus. constant movement in trachea
find more resources at oneclass.com
find more resources at oneclass.com
