Respiratory System, Ventilation and Gas Exchange
Explain ventilation mechanics, diffusion at the alveoli and how breathing supports exercise.
How to prepare for the written examination
Move from accurate theory to a scenario-specific mechanism, consequence, evidence and judgement. Complete all practical performance and NEA work only through authorised centre arrangements.
Core concepts
Concept 1
Ventilation moves air into and out of the lungs through pressure changes created by respiratory muscles.
Exam cue: Describe diaphragm and intercostal action before the resulting pressure and airflow.
Concept 2
Gas exchange occurs by diffusion down concentration gradients across the alveolar-capillary surface.
Exam cue: Distinguish ventilation from respiration and gas exchange.
Concept 3
Alveolar structure supports rapid exchange through large surface area, thin walls and rich blood supply.
Exam cue: Connect increased breathing to the muscle's changing oxygen and carbon-dioxide demands.
Risk pitfalls and guardrails
Claiming the lungs themselves are muscles.
Guardrail: Do not replace explanation with a named sport, an undated current example or practical work that belongs to NEA.
Reversing inhalation and exhalation pressure changes.
Guardrail: Do not replace explanation with a named sport, an undated current example or practical work that belongs to NEA.
Saying oxygen is actively pumped across the alveoli.
Guardrail: Do not replace explanation with a named sport, an undated current example or practical work that belongs to NEA.
Memory anchors
Ventilation meaning
The movement of air into and out of the lungs.
Inhalation pressure
Thoracic volume increases, pressure falls and air moves into the lungs.
Exhalation pressure
Thoracic volume decreases, pressure rises and air moves out.
Alveolar diffusion
Gases move down concentration gradients across a thin exchange surface.
Alveolar adaptation
Large area, thin walls, moisture and rich blood supply support gas exchange.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Which sequence shows the pathway of inhaled air?
What is the main function of the alveoli?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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