OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What effect do stimulants have on nerve impulses?

1. They slow down impulses

2. They increase the amount of chemicals across the synapse

3. They block neurotransmitter receptors

4. They enhance pain responses

The correct answer is: They increase the amount of chemicals across the synapse

Stimulants play a significant role in enhancing nerve impulses by increasing the amount of neurotransmitters released into the synapse, which is the gap between two nerve cells. When stimulants are present, they can lead to a heightened release of neurotransmitters such as dopamine and norepinephrine. This increased availability of neurotransmitters enhances the likelihood that an impulse will be transmitted effectively and quickly across the synaptic cleft, facilitating faster communication between neurons. This is particularly important in the central nervous system, where faster transmission of signals can lead to heightened alertness, improved mood, and increased energy levels. By increasing the chemical activity at the synapse, stimulants ensure that the signals between nerve cells are more robust, resulting in an accelerated response to stimuli. Understanding the impact of stimulants on neurotransmission is essential, particularly in contexts such as medication for attention deficit hyperactivity disorder (ADHD) or in discussions about the effects of recreational drugs. The action of stimulants stands in contrast to other interventions that may either inhibit signal transmission or block neurotransmitter action.