The Respiratory System | OCR A-Level Physical Education (H555)
The Respiratory System
- 60 questions
- 4 subtopics
- Component 01: Physiological factors affecting performance
- Component 01
The Respiratory System is examined in Component 01, Physiological factors affecting performance.
It covers breathing frequency, tidal volume and minute ventilation, mechanics of breathing at rest and in exercise, Regulation of breathing and gas exchange at the alveoli and the muscles.
Sample questions from The Respiratory System
Answer each one closed book first, then open the answer.
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Breathing frequency, tidal volume and minute ventilation
A resting minute ventilation of 6 L/min comes from 12 breaths per minute. What is the tidal volume?
Show the answer
The tidal volume is 0.5 L, or 500 ml. Minute ventilation ÷ frequency = 6 L/min ÷ 12 = 0.5 L. -
Breathing frequency, tidal volume and minute ventilation
Describe the minute ventilation response to submaximal exercise.
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Minute ventilation rises quickly at the start of submaximal exercise. Minute ventilation then plateaus at a steady state where oxygen supply meets demand. -
Mechanics of breathing at rest and in exercise
Explain how air leaves the lungs during expiration at rest.
Show the answer
The ribs move down and in and the diaphragm domes upwards, shrinking the thoracic cavity. Lung pressure rises above atmospheric pressure, so air flows out. -
Mechanics of breathing at rest and in exercise
Why does expiration become active during exercise?
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Fast, deep breathing needs air to be forced out quickly. Muscles contract to shrink the thoracic cavity rapidly rather than relying on elastic recoil. -
Regulation of breathing
Where are the chemoreceptors that regulate breathing found?
Show the answer
Chemoreceptors are found in the medulla oblongata, the aortic arch and the carotid arteries. -
Regulation of breathing
What role do lung stretch receptors play during exercise?
Show the answer
Stretch receptors in the bronchioles detect how far the lungs inflate. The stretch receptors stimulate the expiratory centre, which ends inspiration and prevents over-inflation. -
Gas exchange at the alveoli and the muscles
Describe gas exchange at the muscles at rest.
Show the answer
Arterial blood reaching the muscles has a higher pO₂ than the muscle cells. Oxygen diffuses into the muscle, and carbon dioxide diffuses out into the blood. -
Gas exchange at the alveoli and the muscles
Why is haemoglobin almost fully saturated in the lungs but releases oxygen at the muscles?
Show the answer
The high pO₂ in the lungs lets haemoglobin load oxygen to near full saturation. The low pO₂ in active muscle makes haemoglobin release its oxygen.
The 4 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Breathing frequency, tidal volume and minute ventilation | Breathing frequency, tidal volume and minute ventilation at rest, the minute ventilation equation with worked examples, the tidal volume plateau, and minute ventilation before, during and after submaximal and maximal exercise. | 15 |
| Mechanics of breathing at rest and in exercise | The diaphragm and external intercostals in inspiration, passive expiration at rest, the sternocleidomastoid and pectoralis minor in exercise, active expiration with the internal intercostals and rectus abdominis, and breathing in recovery. | 15 |
| Regulation of breathing | The respiratory control centre and its inspiratory and expiratory centres, the phrenic and intercostal nerves, chemical control by chemoreceptors and carbon dioxide, neural control by proprioceptors, thermoreceptors and lung stretch receptors, and breath-holding. | 14 |
| Gas exchange at the alveoli and the muscles | Partial pressure and pressure gradients at the alveoli and the muscles, alveolar structure, myoglobin, the arterio-venous oxygen difference, the oxyhaemoglobin dissociation curve and the Bohr shift in exercise and recovery. | 16 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
OCR A-Level Physical Education Active Recall Guide
Every topic, not just this one. 2,133 questions with their answers.