Module 2Exchange and transport

1.2.4 Measuring lung capacity

Learning Objectives Success Criteria

• Understand how to measure lung capacity

• To be able to label a spirometer trace

• (PSHE LINK:SMOKING, FITNESS, LUNG CAPACITY)

• Define the terms tidal volume and vital capacity(Grade E - D)

• Describe how a spirometer can be used to measure vital capacity, tidal volume, breathing rate and oxygen uptake (Grade C –B)

• Analyse and interpret data from a spirometer(Grade B – A)

Peak flow meter• Measure the peak expiratory flow rate

(maximum flow of air that can be forced out of the lungs).

• This can show if the airway is blocked in any way.

• Used by asthmatics who can check to see if medication is working.

A “normal” value should be between 400-600 dm3min-1

Starter – Measure your peak flow using a peak flow meter

Spirometer and lung volume

A spirometer consists of a chamber filled with oxygen that floats on water.

A person breathes from a mouthpiece attached to a tube connected to the chamber.

Breathing in takes in oxygen from the chamber, which then sinks down

Breathing out pushes air into the chamber, which then floats up.These movements are recorded using a data logger, so a trace is

recorded.Soda lime – absorbs carbon dioxide exhaled, if the level increases

dangerously. So the total volume of gas in the spirometer goes down. The volume of carbon dioxide breathed out is the same as the volume of oxygen breathed in, so this reduction can be measured allowing us to work out the total oxygen.

•Describe how a spirometer can be used to measure vital capacity, tidal volume, breathing rate and oxygen uptake

(Grade C –B)

Spirometry

•Describe how a spirometer can be used to measure vital capacity, tidal volume, breathing rate and oxygen uptake

(Grade C –B)

Spirometer trace – Label your diagram use page 50

Students in pairs to come up to the front to use the spirometer •Define the terms tidal volume and vital capacity

(Grade E - D)