A condition damages the branched endings of some motor neurones but does not damage their axons.
Scientists stimulate the cell body of a healthy motor neurone and the cell body of an affected motor neurone. Both motor neurones connect to the same type of muscle.
| Observation | Healthy motor neurone | Affected motor neurone |
|---|---|---|
| electrical impulse detected halfway along the axon | yes | yes |
| electrical impulse detected at the branched ending | yes | yes |
| neurotransmitter released at the branched ending / arbitrary units | 8.0 | 0.0 |
| muscle contracts | yes | no |
Explain how the results support the conclusion that the axon and the branched ending have different functions.
The axon of the healthy motor neurone is blocked close to the cell body. Suggest what would happen to the muscle and explain your answer.
111 exam-style questions on Edexcel GCSE Biology 2.3 The nervous system and brain, covering 2.3.1 Structures and functions of the brain, 2.3.2 Imaging brain function with scanning, 2.3.3 Limitations in treating nervous system damage, 2.3.4 Neurones and impulse transmission, and 2.3.5 Structure and function of a reflex arc. Each one has a worked solution and a mark scheme showing where the marks go.