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Collagen
- 12 type of fibre
- each fibril made of 3 polypeptide a-helices
- Types I,II and III microscopically visible
- Type I
- fibrils 50-90 nm in diameter
- occur in dermis, bone, tendon, fascia
- strong - breaking force = several hundred kg cm-2
- Type II
- in hyaline and elastic cartilage, nucleus pulpous of intervertebral
disc and vitreous body of eye
- thin fibrils
- abundant in ground substance
- Type III
- abundant in loose connective tissue, wall of blood vessels, stroma of
glands, spleen, kidneys, uterus
- forms reticular fibres, linked into meshwork by associated proteins
- stains with silver
- Type IV
- restricted to basal lamina of epithelia
- meshwork of fibres provides selective filtration barrier for
macromolecules
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