(6)+Respiratory+system+-+Efficiency+&+cleaning

(1) Respiratory system: efficiency & cleaning
 * List features that make the respiratory system efficient, and explain each one…
 * (Hint moist, thin, SA, passive…)


 * Describe how we keep our respiratory system clean (without even knowing it)
 * Ensure you use each of these words (goblet cell, cilia, mucus, swallow)
 * Diagram to help explain (you will probably have to make it)

Inside our lungs there are bronchi. These are lined with tiny little hairs called Cilia; these fine 'hairs' on the surface of cells can beat in a coordinated way to carry mucus. There is also something called Viscous Mucous that is placed right at the top of the cilia, this Viscous Mucous takes dirt particles, pathogens and other material stuck to the mucous. Mucus often traps microbes as well as dust flowing down the bronchus away from the lungs. These hairs pick up dust and other particles in the air. Only particles with a diameter less than 3-5 microns will get to the inner lung. When this system doesn't function properly, coughing occurs (although this isn't the only reason for coughing). There is also a liquid layer of mucus in the airways picking up particles and pathogen. Cilia propels the mucus at a rate of about 0.5-1.0cm per minute. The mucus goes to the mouth and gets swallowed.

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*Diffuse: for particles to move from an area of higher concentration to an area of lower concentration
 * **Property of Surface** || **Reason** ||
 * Thin (best one cell thick) || Gases have a shorter distance over which to diffuse*. ||
 * Large surface area || Many molecules of gas can diffuse* across at the same time. ||
 * Moist || Cells die if not kept moist ||
 * Well ventilated || Concentration gradient for oxygen and carbon dioxide are kept up by regular supplies of fresh air. ||
 * Close to a blood supply || Gases can be carried to and from the cells that need or produce them. ||