A doctor measures the response times of a patient for three different responses.
The Table shows the results.
Table
| Response | Number of synapses in the pathway | Mean response time in ms\text{ms}ms |
|---|---|---|
| knee-jerk reflex | 1 | 25 |
| moving the hand away from a hot object | 2 | 40 |
| catching a falling ruler | many | 200 |
Use the Table and your own knowledge to explain the differences in response time.
The doctor tests the knee-jerk reflex in the patient's left leg. The leg does not move.
Suggest what this shows.
The knee-jerk reflex in the patient's right leg is normal. The patient tries to stop his right leg moving when his knee is tapped, but he cannot.
Explain why.
135 exam-style questions on OCR GCSE Biology 3.1 Coordination and control – the nervous system, covering 3.1.1 Structure of the nervous system, 3.1.2 Coordinated response, 3.1.3 The reflex arc, 3.1.4 Structure of the eye, 3.1.5 Defects of the eye, 3.1.6 Structure and function of the brain, 3.1.7 Difficulties of investigating brain function, and 3.1.8 Limitations in treating nervous system damage. Each one has a worked solution and a mark scheme showing where the marks go.