Photo AI
Figure 2 shows part of a reflex arc in the spinal cord - Edexcel - GCSE Biology - Question 2 - 2021 - Paper 1
Question 2
Figure 2 shows part of a reflex arc in the spinal cord. a) (i) Describe how an impulse passes from the relay neurone to the motor neurone. (3) (ii) Explain the fun... show full transcript
Worked Solution & Example Answer:Figure 2 shows part of a reflex arc in the spinal cord - Edexcel - GCSE Biology - Question 2 - 2021 - Paper 1
Step 1
Describe how an impulse passes from the relay neurone to the motor neurone.
Answer
The process begins with the impulse in the relay neurone triggering the release of a neurotransmitter. This chemical messenger then diffuses across the synapse, the small gap between neurons. As the neurotransmitter crosses this gap, it stimulates the motor neurone, triggering a new impulse in it.
Step 2
Explain the function of a reflex arc.
Answer
A reflex arc is a process that occurs in response to danger. It bypasses the brain, allowing for a quicker response through the spinal cord without conscious thought. This facilitates faster transmission of electrical impulses, helping to protect the body from harm by enabling actions such as pulling away from a painful stimulus.