Peer mark homework exam questions

Module 3 Exchange and transport 7.3 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 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)

Peak flow meter Starter – Measure your peak flow using 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. 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

Spirometer and lung volume 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. Explain risk assessment check health of volunteer ; oxygen used ; new / sterilised / disinfected mouthpiece (for each volunteer); idea of: soda lime working ; sufficient oxygen in chamber ; water level not too high

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)

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? 1) Convert to cm3 first – 6000/500 = 12 breaths/min 2) 15000/20 – 750 cm3

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)

Self assessment Diffusion A) tidal volume – 0.3dm3 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

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