BIOL302 Lecture Notes - Lecture 2: Stratified Squamous Epithelium, Basal Lamina, Tight Junction
21 Apr 2017
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Document Summary
Surface epithelia cover or line all body surfaces. Epithelia cells are bound to adjacent cells by a variety of cell junctions. All epithelia supported by basement membrane separates epithelia from underlying supporting tissues and never contain blood vessels. One side faces basement membrane basal surface: basal lamina - epithelial origin, reticular lamina of connective tissue. Other faces outwards free apical surface. Lining of blood vessels and lymphatic vessels = endothelium. In stratified, shape of the outermost layer of cells determined the shape. Surface/apical specialization: keratinized skin = keratinized stratified squamous epithelium, microvilli refer to as brush border eg; digestive tract. Prevents movement between cells: adherens junction. Epithelium involved in secretion is arranged into structures called glands. Some solid organs composed of epithelial cells with a supporting tissue framework. Some of these organs are connected to surface epithelium of gastrointestinal tract by branching system of ducts exocrine glands eg salivary glands. Endocrine glands lost connection to epithelial surface secrete into blood.
