Mechanics of breathing and interpretation of a spirometer trace
Lesson details
Learning outcome
I can explain the mechanics of breathing and how lung volumes are measured.
Key learning points
- During inhalation the intercostal muscles and diaphragm contract to expand the thoracic cavity volume, so air rushes in.
- During exhalation the intercostal muscles relax, the rib cage returns to its resting position and air is expelled.
- During exercise the lungs can expand more using the pectoralls and sternocleidmastoid.
- Expiration is aided by the abdominals pulling the ribs down quicker to force air out.
- A spirometer trace is a graphical representation of lung volume changes over time during breathing.
Keywords
Tidal volume - the volume of air breathed in or out during normal breathing
Inspiratory reserve volume - the additional volume of air that can be forcefully inhaled after a normal inhalation
Expiratory reserve volume - the additional volume of air that can be forcefully exhaled after a normal exhalation
Residual volume - the amount of air that remains in the lungs after maximal expiration
Common misconception
Tidal volume is the amount of air breathed in and out per breath and the lungs completely empty of air when we expire.
Tidal volume is the volume of air breathed in or out per breadth and it increases during exercise to enable more air and hence exchange of oxygen and carbon dioxide to occur. A residual volume of air always remains in the lungs to keep them inflated.
Teacher tip
Check with your science department as they often have a nice visual aid of a glass jar with balloons in it to represent the chest cavity and show how diaphragm movement down helps inflate the lungs due to an increase in volume and hence reduction in pressure withinn the chest (thoracic) cavity.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Where does air enter the body?
Q2.The process of switching oxygen for carbon dioxide is known as exchange.
Q3.Match the following key terms with the correct description.
Q4.Which of the following does not describe the process of diffusion?
Q5.Arrange these body parts in the correct order of inhaled air starting at the atmosphere.
Q6.Gaseous exchange happens between the and the bloodstream thanks to large capillary networks.
Assessment exit quiz
6 Questions
Q1.Which of the following terms refers to breathing in?
Q2.What happens as we breathe in?
Q3.The muscles help pull the rib cage down and in faster when exhaling during exercise.
Q4.Match the following key terms with the correct description.
Q5.Arrange these key processes in the correct order to represent what happens when we breathe in.
Q6.Which of the following additional muscles are recruited to aid expiration during exercise?
To help you plan your 10 physical education lesson on: Mechanics of breathing and interpretation of a spirometer trace, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 physical education lesson on: Mechanics of breathing and interpretation of a spirometer trace, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 physical education lessons from the Anatomy and physiology: the cardio-respiratory system unit, dive into the full secondary physical education curriculum, or learn more about lesson planning.