6.4+Gas+exchange

6.1 Digestion - 6.2 The transport system - 6.3 Defence against infectious disease - 6.4 Gas exchange - 6.5 Nerves, hormones and homeostasis - 6.6 Reproduction - Physiology Labs

6.4 Gas exchange

 * Assessment statements** (IBO notes added to some points to clearly indicate what needs to be understood and what does not)
 * 6.4.1 || Distinguish between ventilation, gas exchange and cell respiration. ||
 * 6.4.2 || Explain the need for a ventilation system. A ventilation system is needed to maintain high concentration gradients in the alveoli. ||
 * 6.4.3 || Describe the features of alveoli that adapt them to gas exchange. This should include a large total surface area, a wall consisting of a single layer of flattened cells, a film of moisture and a dense network of capillaries. ||
 * 6.4.4 || Draw and label a diagram of the ventilation system, including trachea, lungs, bronchi, bronchioles and alveoli. Students should draw the alveoli in an inset diagram at a higher magnification. ||
 * 6.4.5 || Explain the mechanism of ventilation of the lungs in terms of volume and pressure changes caused by the internal and external intercostal muscles, the diaphragm and abdominal muscles. ||

Respiration, breathing and gas exchange - what do those terms mean and how are they related? Discuss.
 * Starter**

Visit the [|DCS bridge]and download the workbook for this topic. Word versions of workbooks available below for those unable to access the DCS Bridge. media type="custom" key="23684610"
 * Workbook and Worksheets**

The [|i-Biology] presentation is a great starting point media type="custom" key="23684612"
 * Presentations and Tutorials**

The Khan Academy [|video tutorial] is a useful resource which will help you understand some of your assessment statements. media type="custom" key="24046836"

[|Click4Biology] summarises gas exchanges concisely.

This is a [|youtube video] which does a nice job of showing a heart and lung dissection
 * Useful links**