Key Concept: Coordinated responses use receptors, coordinators, and effectors to maintain a stable internal environment.
Section A: Key Terms
1. Define stimulus, receptor, and effector. [3]
Section B: Homeostasis
2. Define homeostasis and give two examples. [3]
Section C: Pathway
3. Describe the pathway of a coordinated response from stimulus to response. [4]
Total marks: 10
Mark Scheme
1. Stimulus: change in environment; receptor: detects stimulus; effector: muscle/gland causing response [3]
2. Maintenance of constant internal conditions; examples include body temperature and water content (any two) [3]
3. Stimulus -> receptor -> coordinator (CNS/hormone) -> effector -> response (all steps) [4]