Edexcel iGCSE Biology-3.36 Nervous & Hormonal Control- Study Notes- New Syllabus
Edexcel iGCSE Biology-3.36 Nervous & Hormonal Control- Study Notes- New syllabus
Edexcel iGCSE Biology-3.36 Nervous & Hormonal Control- Study Notes -Edexcel iGCSE Biology – per latest Syllabus.
Key Concepts:
3.36 describe how nervous and hormonal communication control responses and understand the differences between the two systems
Nervous vs Hormonal Communication
🌱 Introduction
Living organisms need to respond to changes (stimuli) in their surroundings to survive.
They do this using:
- Nervous System → fast, electrical control
- Endocrine System → slower, chemical control
Both systems work together to maintain homeostasis and coordinate body activities.
⚡ Nervous Communication
- Uses electrical impulses that travel along neurons (nerve cells).
- Transmission is very fast.
- Effects are immediate but short-lived.
- Highly specific (targets one muscle or gland).
- Involves the CNS (brain + spinal cord).
🔹 Examples:
- Pulling your hand away from a hot surface
- Blinking when something comes near the eye
💉 Hormonal Communication
- Uses hormones (chemical messengers) carried in the bloodstream.
- Transmission is slower than nerve impulses.
- Effects are usually long-lasting.
- Can affect multiple organs at the same time.
- Produced by endocrine glands (e.g., pancreas, adrenal glands).
🔹 Examples:
- Insulin lowering blood glucose levels
- Adrenaline increasing heart rate (“fight or flight”)
📊 Nervous vs Hormonal System
| Feature | Nervous System | Hormonal System |
|---|---|---|
| Signal type | Electrical impulse | Chemical messenger |
| Speed | Very fast | Slower |
| Duration | Short-lived | Long-lasting |
| Transport | Neurons | Blood |
| Target | Specific (muscle/gland) | Can be widespread |
| Example | Reflex actions | Insulin, adrenaline |
📌 Quick Recap
Nervous = fast, electrical, short-term, specific.
Hormonal = slow, chemical, long-term, widespread.
Both = vital for coordination + survival.