cilia

Examples of cilia in the following topics:

• Cilia and Flagella

• Flame Cells of Planaria and Nephridia of Worms

  • The cells in the tubules are called flame cells (or protonephridia) because they have a cluster of cilia that looks like a flickering flame when viewed under the microscope .
  • The cilia propel waste matter down the tubules and out of the body through excretory pores that open on the body surface; cilia also draw water from the interstitial fluid, allowing for filtration.
  • They are similar to flame cells in that they have tubules with cilia and function like a kidney to remove wastes, but they often open to the exterior of the organism.
  • In the excretory system of the (a) planaria, cilia of flame cells propel waste through a tubule formed by a tube cell.

• Intermediate Filaments and Microtubules

  • Microtubules are also the structural elements of flagella, cilia, and centrioles (the latter are the two perpendicular bodies of the centrosome).
  • In eukaryotic cells, flagella and cilia are quite different structurally from their counterparts in prokaryotes.
  • When cilia (singular = cilium) are present, however, many of them extend along the entire surface of the plasma membrane.
  • They are short, hair-like structures that are used to move entire cells (such as paramecia) or substances along the outer surface of the cell (for example, the cilia of cells lining the Fallopian tubes that move the ovum toward the uterus, or cilia lining the cells of the respiratory tract that trap particulate matter and move it toward your nostrils).
  • Despite their differences in length and number, flagella and cilia share a common structural arrangement of microtubules called a "9 + 2 array."

• Whooping Cough

  • The bacterium contains a surface protein, filamentous haemagglutinin adhesin, which binds to the sulfatides found on the cilia of epithelial cells.
  • Once anchored, the bacterium produces tracheal cytotoxin, which stops the cilia from beating.
  • This prevents the cilia from clearing debris from an organism's lungs, and the body responds by sending the host into a coughing fit.

• Physical and Chemical Barriers

  • These include tears in the eyes; mucous membranes that provide partial protection despite having to allow absorption and secretion; mucus secretions that trap and rinse away pathogens; and cilia (singular cilium) in the nasal passages and respiratory tract that push the mucus with the pathogens out of the body .
  • Despite these barriers, pathogens may enter the body through skin abrasions or punctures, or by collecting on mucosal surfaces in large numbers that overcome the mucus or cilia.
  • Cilia are a type of organelle found in eukaryotic cells.

• Female Duct System

  • Estrogen increases the production of cilia on these cells.
  • Tubal fluid flows against the action of the ciliae, that is toward the fimbrated end.
  • The egg is caught by the fimbriated end and travels to the ampulla where typically the sperm are met and fertilization occurs; the fertilized ovum, now a zygote, travels towards the uterus aided by activity of tubal cilia and activity of the tubal muscle.

• Phylum Rotifera

  • Rotifers are microscopic organisms named for a rotating structure (called the corona) at their anterior end that is covered with cilia.
  • The rotifers are a microscopic (about 100 µm to 30 mm) group of mostly-aquatic organisms that get their name from the corona: a rotating, wheel-like structure that is covered with cilia at their anterior end.

• Mammalian Systems and Protective Mechanisms

  • The bronchi and bronchioles contain cilia, small hair-like projections that line the walls of the bronchi and bronchioles .
  • These cilia move mucus and particles out of the bronchi and bronchioles back up to the throat where it is swallowed and eliminated via the esophagus.
  • In humans, tar and other substances in cigarette smoke destroy or paralyze the cilia, making the removal of particles more difficult.
  • In addition, smoking causes the lungs to produce more mucus, which the damaged cilia are unable to move.
  • The bronchi and bronchioles contain cilia that help move mucus and other particles out of the lungs.

• Chromalveolata: Alveolates

  • The ciliates, which include Paramecium and Tetrahymena, are a group of protists 10 to 3,000 micrometers in length that are covered in rows, tufts, or spirals of tiny cilia.
  • By beating their cilia synchronously or in waves, ciliates can coordinate directed movements and ingest food particles.
  • Certain ciliates have fused cilia-based structures that function like paddles, funnels, or fins.
  • The genus Paramecium includes protists that have organized their cilia into a plate-like primitive mouth called an oral groove, which is used to capture and digest bacteria .
  • Cilia enable the organism to move.

• Cell Structure, Metabolism, and Motility

  • Paramecia are covered in rows of tiny cilia that they beat to swim through liquids.
  • (a) A paramecium waves hair-like appendages called cilia.