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Biology · Paper 2 · Higher Tier only · B5

Higher: adrenaline, thyroxine and feedback

Key ideas1 of 3

Adrenaline prepares the body

The adrenal glands release adrenaline in fear or stress. It increases heart rate and delivery of oxygen and glucose to the brain and muscles. Increased respiration supplies energy for muscle contraction: the fight-or-flight response.

Adrenaline from an adrenal gland above a kidney enters the blood and acts on the heart and muscles, increasing heart rate and the supply of oxygen and glucose to muscles.

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Higher Tier only · B5. Nine core lessons, followed by four labelled Higher Tier lessons.

AQA Combined Science Trilogy 8464 · 4.5.3.6. Original notes, questions and diagrams. Models are simplified; teaching data are illustrative.