This summary Human Biology includes books, slides and lecture notes. Titles are clearly marked in color, and expressed figures are all included. The text is written in English. Good luck, it worked for me ;-)!
… and NUMBER OF LAYERS :
• Simple/single-layered epitheleum : molecules can pass through easily => diffusion across cell barriers. Glands +
respiratory-digestive-reproductive systems
• Stratified/multiple-layered epitheleum : Provides protection for underlying cells (e.g. the skin surface)
The BASEMENT MEMBRANE provides structural support
Basement membrane = a supporting noncellar layer directly beneath the cell of an epithelial tissue (and beneath that
one, is a layer of connective tissue – see later) => Anchors the epithelial cells to the strong connective tissue below.
Consists proteins secreted by the epithelial cells & by underlying connective tissue layer. (is NOT plasma membrane =
part of living cell!!)
Epithelial cells may also be connected to eachother in 3 types of junctions made up by different PROTEINS :
Tight junctions : seal plasma membranes of adjecent cells so tightly that nothing can pass => controls movement
of substances in/out our body (digestive tract, bladder, tubules kidneys)
Adhesion junctions : “spot demosomes”, looser. Tissues can strectch & bend (skin)
Gap junctions : Connecting channels for movement of water & ions between adjacent cells. (liver, heart, muscles).
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