These are non-living structures.
Made up of different types of protein eg. Keratin, synemin, desmin and vimentin.
These are divided into four groups -
(a) Keratin fibers - Present in skin cells, helps in attachment of desmosomes.
(b) Heterogenous fibers - Synamin fibres, desmin fibres and vimentin fibers, present in epidermal cells
(c) Glial fibres - Present in nerve cells.
(d) Neuro glial fibres - Present in neurons.
Intermediate filaments form a basket around nucleus.