3. At the end of this class you should be able to ..
• Define epithelium
• Classify epithelium with examples
• Correlate epithelium with their function
5. DEFINITION: layer (s) of cells that covers body surfaces,
lines body cavities or constitute glands
6. DEVELOPMENT
• From all three germ layers
• Ectoderm - skin, mouth, nose, anal canal
• Endoderm - GIT, glands, resp tract, distal parts
of GU tract
• Mesoderm - body cavities, endothelium,
proximal parts of GU tract
8. FUNCTIONS
•Secretion- columnar epithelium of stomach and gastric
gland
•Absorption- columnar epithelium in intestine and PCT
in kidney
•Transportation- material of cells along the surface of
epithelium by motile cilia
•Protection- skin and urothelium in bladder
•Receptor- taste and olfaction
•Lubrication
31. CONTACTS BETWEEN ADJOINING
CELLS
CLASSIFICATN OF CELL CONTACTS
1. UNSPECIALISED CONTACTS
2. SPECIALISED JUNCTIONAL STRS
A. Occluding jns or Zonula occludens or
tight jns
B. Anchoring jns or Adhesive jns
• Adhesive belts or Zonula adherens
• Adhesive strips or Fascia adherens
• Adhesive spot (Desmosomes, Maculae
adherens)
A. Communicating jns or gap jns
36. GAP JUNCTION
•Lateral surface of epithelial cells
•Numerous transmembrane protein channels
•Permit inorganic ions, small molecules, nutrients,
chem messengers