This key facts covers Breathing Rate Control within Gas Exchange in Humans for GCSE Biology. Lung structure, alveoli adaptations, breathing mechanism, gas transport in blood, and effects of smoking It is section 8 of 19 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 8 of 19
Practice
19 questions
Recall
23 flashcards
Breathing Rate Control
Automatic Control Centre
The medulla oblongata in the brain stem automatically controls breathing rate:
- Primary trigger: CO₂ concentration in blood (not oxygen!)
- Chemoreceptors detect changes in blood pH (caused by CO₂ levels)
- High CO₂ → more acidic blood → increased breathing rate
- Low CO₂ → less acidic blood → decreased breathing rate
Factors Affecting Breathing Rate
Exercise: Increases CO₂ production → faster breathing
Emotions: Stress, fear → adrenaline → faster breathing
Temperature: High fever → increased metabolic rate → faster breathing
Altitude: Low oxygen → breathing rate increases (but slowly adapts)