Background/history
  • 'Cilium' (Latin for eyelash)
  • Motile (bear the specialized ciliary and flagella machinery for generating fluid flow or movement within fluids.) discovered by Anthony van Leeuwenhoek in 1675 and sensory cilia (ability of a wide variety of cells and organisms to sense their chemical and physical environments.)


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Function and appearance
Microscopic hairlike structures that extend from almost all mammalian cells. 1-10 micrometres long 1 micrometre wide
  • They work, for instance, to keep the airways clear of mucus and dirt, allowing us to breathe easily and without irritation. They also help propel sperm.
  • They move liquids and other substances over the cell so the materials don't clog and block the cell membrane using the flow of their flexible structure
  • Some act as a sensory antenna for the cell, receiving signals from other cells or fluids nearby.

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They are only found in eukaryotic cells, all cells have sensory cilia, which are found on the interior of the cell for flow of organelles and to compare the cells chemical levels. Only certain body cells have exterior or motile cilia because not all cells are moving liquids or other material along the cell’s membrane.

Epithelial cells lining our air passages require cilia and flagella to move mucus over itself to get to throat lining. Another example is in the kidney, the cilia on cells are used to signal the flow of urine

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Microtubules are used inside the cell to move vesicles and mitochondria, but when they combine, they may form either cilia or flagella (depending on if they are motile or not) and can be found by the nucleus to aid in cell division.

Analogy
bristles are to a toothbrush as cilia is to a cell