Edexcel iGCSE Biology-3.32 Co-ordinating Response- Study Notes- New Syllabus
Edexcel iGCSE Biology-3.32 Co-ordinating Response- Study Notes- New syllabus
Edexcel iGCSE Biology-3.32 Co-ordinating Response- Study Notes -Edexcel iGCSE Biology – per latest Syllabus.
Key Concepts:
3.32 understand that a co-ordinated response requires a stimulus, a receptor and an effector
Coordinated Response: Stimulus → Receptor → Effector
🌱 Introduction
Organisms need to respond to changes in their surroundings (environment).
A coordinated response ensures the body reacts correctly and efficiently.
🔹 Key Terms
- Stimulus → A change in the environment (e.g., light, temperature, sound).
- Receptor → A cell or organ that detects the stimulus (e.g., eyes, skin, ears).
- Effector → A muscle or gland that carries out the response.
🔹 Pathway of a Response
- Stimulus is detected.
- Receptor senses the change.
- Information is sent to the control center (brain/spinal cord).
- The effector produces a response.
👉 This ensures the body maintains survival and homeostasis.
📊 Example Table
| Example Stimulus | Receptor | Effector | Response |
|---|---|---|---|
| Bright light | Eye (retina) | Pupil muscles | Pupil contracts to reduce light entry |
| Hot surface | Skin receptors | Arm muscles | Hand pulls away |
| Low blood sugar | Pancreas | Liver (releases glucose) | Blood sugar restored |
⚡ Quick Recap
Stimulus → Receptor → Effector = pathway of a coordinated response.
Receptors detect changes, effectors carry out actions.
Examples:
Bright light → eye → pupil contracts.
Heat → skin → hand withdraws.
👉 Trick: Remember S.R.E. → Stimulus, Receptor, Effector (like “Some Responses Exist”).