Properties of Epithelial Tissue
Epithelial tissue is avascular – lacks its own blood supply
Epithelial tissue is innervated – has its own nerve supply
Epithelial tissue has a high rate of cell division – allowing for regeneration.
Types of Epithelial Tissue:
1. Covering and Lining Epithelium
Covering and lining epithelium are classified according to 2 characteristics: arrangement of cells into layers and shapes of cells. a) Simple Epithelium : composed of one single layer of cells that functions in diffusion, osmosis, filtration, secretion, or absorption. 1) Simple Squamous Epithelium: A single layer of flat cells that resembles floor tiles when viewed from the apical surface. Present at sites of filtration or diffusion.
Examples:
2) Simple Cuboidal Epithelium: Cuboidal shaped and functions in secretion and absorption.
Examples:
3) Simple Columnar Epithelium: When viewed from the side, these appear like columns. 2 types: Nonciliated which contain microvilli at the apical surface and goblet cells (modified columnar cells that secrete mucus serving as a lubricant for linings). Ciliated contain cilia at the apical surface which beat in unison moving mucus and tiny foreign particles over surfaces.
Examples:
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