Edexcel A Level (IAL) Biology -7.14 The Role of Adrenaline- Study Notes- New Syllabus
Edexcel A Level (IAL) Biology -7.14 The Role of Adrenaline- Study Notes- New syllabus
Edexcel A Level (IAL) Biology -7.14 The Role of Adrenaline- Study Notes -Edexcel A level Biology – per latest Syllabus.
Key Concepts:
- 7.14 understand the role of adrenaline in the fight or flight response
Adrenaline in the Fight or Flight Response
🌟 Introduction
When the body senses danger, it switches into survival mode. Adrenaline prepares the body to fight the threat or escape from it. This response is controlled by the sympathetic nervous system and the adrenal glands.
🔥 What Is Adrenaline?
- A hormone and neurotransmitter.
- Released from the adrenal medulla.
- Acts rapidly on many organs.
Key point: Adrenaline prepares the body for immediate action.
⚡ How Adrenaline Is Triggered
- A threat or stress is detected by the hypothalamus.
- Sympathetic nerves activate the adrenal medulla.
- Adrenaline is released into the bloodstream.
- Target organs respond instantly.
💥 Effects of Adrenaline (Fight or Flight Changes)
1. Heart
- Increases heart rate and stroke volume.
- Delivers more oxygen to muscles.
2. Lungs
- Bronchioles widen.
- Breathing becomes faster and deeper.
3. Muscles
- Increased oxygen and glucose flow.
- Improved strength and reaction speed.
4. Liver
- Stimulates glycogen breakdown into glucose.
- Boosts blood glucose for quick energy.
5. Eyes
- Pupils dilate.
- Enhanced alertness and vision.
6. Nervous system
- Faster nerve impulses.
- Sharper awareness and quicker decisions.
7. Blood flow
- Directed more towards muscles and brain.
- Reduced flow to digestive organs.
🌟 Why These Effects Matter
These changes help the body run faster, react quickly, fight effectively and stay alert during emergencies. It allows the body to survive sudden threats.
Memory trick: Adrenaline makes the body “power up”.
📌 Summary Table
| System | Effect of Adrenaline | Purpose |
|---|---|---|
| Heart | Faster, stronger beats | More oxygen to muscles |
| Lungs | Wider airways | Increase oxygen uptake |
| Liver | Glycogen to glucose | Quick energy supply |
| Eyes | Pupils dilate | Better vision |
| Muscles | Increased blood flow | Strong rapid movements |
| Nervous system | Faster signals | Quick reactions |
| Digestive system | Reduced activity | Save energy for emergency |
Adrenaline is released from the adrenal medulla during danger.
Triggered by the sympathetic nervous system.
Raises heart rate, breathing and blood glucose.
Diverts blood to muscles and brain.
Prepares the body for fast, powerful responses.
Essential for fight or flight survival.