Module 3 Exchange and transport

3. Module 3Exchange and transport 7.3 Measuring lung capacity

4. Success Criteria Learning Objectives Understand how to measure lung capacity To be able to label a spirometer trace (PSHE LINK:SMOKING, FITNESS, LUNG CAPACITY) Define the key terms (Grade E - D) Describe the relationship between vital capacity, tidal volume, breathing rate and oxygen uptake (Grade C –B) Analyse and interpret primary and secondary data from a spirometer PAG10 (Grade B – A)

5. Starter – Measure your peak flow using a peak flow meter 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. • Vitalograph – patient breathes out as quickly as they can and instrument produces a graph, the volume of air is called forced expiratory volume in 1 second A “normal” value should be between 400-600 dm3min-1

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

7. Spirometer trace – Label your diagram use page 50 with definitions Students in pairs to come up to the front to use the spirometer • Define the terms tidal volume and vital capacity (Grade E - D)

8. Breathing rhythms • As the demands of the body changes so does the pattern and volume of breathing. • The breathing rate is the number of breaths per minute. • Ventilation rate is the total volume of air inhaled on one minute. Ventilation rate = tidal volume x breathing rate (per minute) Questions • Normal tidal volume of a male is 500cm3, his ventilation rate is 6dm3 per minute. What is his resting breathing rate? • During exercise his breathing rate goes up to 20 breaths per minute and ventilation rate to 15dm3. What is his new tidal volume?

9. Analyse and interpret data from a spirometer (Grade B – A) Task • Students to use the spirometer and analyse the data on their trace (nose clip not available – why is this important?) • http://www.nuffieldfoundation.org/practical-biology/using-spirometer-investigate-human-lung-function • Answer questions 1-5 on page 51 • Self mark answers • Describe how a spirometer can be used to measure vital capacity, tidal volume, breathing rate and oxygen uptake (Grade C –B)

10. Self assessment • Analyse and interpret data from a spirometer (Grade B – A) • Diffusion • A) tidal volume – 0.3dm3 breaths per minute – 13 B) tidal volume – 1 dm3 breaths per minute – 22 3. 2 dm3min-1 4. Larger tidal volume and more breaths per minute 5. So tidal volume and breathing rate increase Show of hands - /8

11. Plenary • Jeopardy: Students have to write the question when given the answer. • Tidal volume • Vital capacity • Breathing rate • Soda lime • Spirometer • Inspiration • Expiration