IMED1001 Lecture Notes - Lecture 5: Esophagus, Cell Junction, Respiratory System
IMED1001: Lecture 5 Notes - Epithelial Tissue
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Covering eg. Skin:"
-Covering = part of the skin"
-Skin is an organ itself"
-Skin = epithelium + specialisation + CT"
Lining:
-Lines the internal surfaces "
-Eg. Digestive system "
-Eg. Respiratory system"
-Eg. Heart + BV"
General Features:
-Cells are compactly arranged"
-Small gaps between cells = junctions"
-Junctions between cells functions:"
1. Integrity of epithelium"
2. Control passage of substances"
-Compact arrangement in epithelium mean that there is no BV"
-No BV = avascular"
-Cells (epithelium) rest on basement membrane "
-BM = non-cellular (partly produced by epithelial cell)"
Cell Junctions:
-Only can be seen with EM"
-Many types of cell junctions "
-All with different functions"
1. Adhering junctions "
-Strong bonds for integrity"
-Not permanent "
-Can be lost from an epithelium"
2. Occluding junctions"
-Used to seal off intercellular space"
-Control substances passing through into the cytoplasm"
3. Gap junctions"
-For communication between cells"
-Special proteins participate as cell junctions"
-Cell junctions can occur in other tissues"
