MrBadmusAutumn First Half

Year 8 · Autumn First Half

Biology

4 lessons from 1 unit.

Unit B4 · lessons 1 to 4 of 5

Breathing and gas exchange

You breathe about twenty thousand times a day without deciding to. This unit is about what the air is for, how it gets in and out when your lungs contain no muscle at all, and why the same problem has the same solution in a lung and in a leaf.

  1. 01The gas exchange systemSystemEvery breath goes in and comes back out. What actually changes in the air while it is inside you?Open this lesson
  2. 02How breathing worksModelAir flows into your lungs with every breath. What makes it go in?Open this lesson
  3. 03Alveoli: built for exchangeModelOxygen molecules cross from your alveoli into your blood, and at the same moment other oxygen molecules cross the other way. You survive on the difference between two numbers.Open this lesson
  4. 04Exercise, asthma and smokingSystemThree things that change how well you breathe, and they act on three different parts of the system. Naming which part is most of the answer.Open this lesson

Back to all three sciences this half term The whole KS3 Biology course