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Exercise causes an increase in heart rate - AQA - A-Level Biology - Question 1 - 2017 - Paper 1
Question 1
Exercise causes an increase in heart rate. Describe the role of receptors and of the nervous system in this process.
Worked Solution & Example Answer:Exercise causes an increase in heart rate - AQA - A-Level Biology - Question 1 - 2017 - Paper 1
Step 1
1. Chemoreceptors detect rise in CO₂/H⁺/acidity/carbonic acid/fall in pH
Answer
Chemoreceptors are specialized cells that monitor changes in the blood's chemical composition. When exercise occurs, levels of CO₂ and acidity in the blood increase due to heightened metabolic activity, triggering these receptors.
Step 2
Step 3
Step 4
4. By sympathetic (nervous system for chemoreceptors/CO₂) OR By parasympathetic (nervous system for baro/pressure receptors/blood pressure)
Answer
The sympathetic nervous system's activation further supports heart rate elevation by facilitating faster heartbeats, while the parasympathetic system diminishes its activity. Both systems work in concert to finely tune the heart's response during physical exertion.