CIE IGCSE Biology: 复习笔记:11.1.11 Protecting the Breathing System: Extended

CIE IGCSE Biology: 复习笔记:11.1.11 Protecting the Breathing System: Extended

Protecting the Breathing System: Extended

 

  • The passages down to the lungs are lined with ciliated epithelial cells
  • Cilia comes from the Latin for eyelash, so unsurprisingly these cells have tiny hairs on the end of them that beat and push mucus up the passages towards the nose and throat where it can be removed
  • The mucus is made by special mucus-producing cells called goblet cells because they are shaped like a goblet, or cup
  • The mucus traps particles, pathogens like bacteria or viruses, and dust and prevents them getting into the lungs and damaging the cells there

 

 

Ciliated-CellsMucus traps particles, dust and pathogens and cilia beat and push it up and away from the lungs

 

 

Exam Tip

The function of cilia and mucus is often a 3-mark question on the extended paper.The examiners are looking for you to state the following:

 

 

  1. The mucus is produced by goblet cells and traps bacteria, dust, particles
  2. The cilia beat
  3. And push the mucus away from the lungs towards the throat

 

This is quite simple, but often marks are lost as students haven’t been precise enough with their explanations!

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