Specification: 1.2.1 Exchange Surfaces and Breathing

- explain, in terms of surface area:volume ratio, why multicellular organisms need specialised 
   exchange surfaces and single-celled organisms do not
- describe the features of an efficient exchange surface, with reference to diffusion of oxygen 
   and carbon dioxide across an alveolus; 
- describe the features of the mammalian lung that adapt it to efficient gaseous exchange; 
- describe, with the aid of diagrams and photographs, the distribution of:
      - cartilage
      - ciliated epithelium
      - goblet cells
      - smooth muscle
      - elastic fibres 
            - in the trachea, bronchi, bronchioles and alveoli of the mammalian gaseous exchange system; 
- describe the functions of:
      - cartilage
      - cilia
      - goblet cells
      - smooth muscle 
      - elastic fibres 
            - in the mammalian gaseous exchange system; 
- outline the mechanism of breathing (inspiration and expiration) in mammals, with 
   reference to the function of:
      - the rib cage
      - intercostal muscles 
      - diaphragm; 
- explain the meanings of the terms tidal volume and vital capacity;
- describe how a spirometer can be used to measure:
      - vital capacity
      - tidal volume
      - breathing rate 
      - oxygen uptake; 
- analyse and interpret data from a spirometer