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๐Ÿ“š > Physiology > General Physiology > Cells and Molecules_>

Cell Cytoskeleton

  • provides structural support to the cell and determines its shape.

  • is a network of fibrillar proteins.

  • These fibrilar proteins are synthesized by polymerization of precursor molecules โ†’ if not needed anymore โ†’ disassemble โ†’ reassemble where and where needed โ†’ thus the cytoskeleton can be dynamic as needed.

  • Components:

  • Microtubules

  • Filaments

  • Thin filaments

  • Thick filaments

  • Intermediate filament


  • polymer of tubulin.

  • have a hollow lumen at the center.

  • 20-30 nm in diameter.

  • Form and move structures like:

  • Cilia

  • Flagella

  • Centrioles

  • Mitotic spindle

  • Form a track for intracellular organelles to move from one area of the cell to the other

Thin & Thick Filaments

  • Thin filaments are made up of actin

  • Thick filaments are made up of myosin

Functions: They play role in...
  • Muscle contraction

  • Cell movement e.g. gliding, cytokinesis

  • Extend process from cell e.g.

  • Formation of axon in neuron

  • Formation of microvilli in epithelial cells

Intermediate Filaments

  • There is a large variety of subunit proteins that can form intermediate filaments.

  • Expression of different subunits in different cells results in formation of different intermediate filaments in different cells. For example:

  • Epithelial cells have keratins

  • Nerve cells have neurofilaments

  • Muscle cells have desmin

  • Radiate from the cell area subject to tensile stress โ†’ Reinforce such area against tensile stress.

  • In epithelial cells, they insert at the desmosomal junctions that attach neighboring cells to one another.


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โ–ถ๏ธ Endocytosis
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