Associate Certified Entomologist (ACE) Practice Exam

What effect does acetylcholabine have in the synapse?

1. Causes increased inhibition of nerve signaling

2. Prevents muscle contraction

3. Stimulates continuous signaling

4. Blocks nerve transmission

The correct answer is: Stimulates continuous signaling

Acetylcholine is a critical neurotransmitter involved in the transmission of signals across synapses, particularly at the neuromuscular junction and within the central nervous system. When released into the synaptic cleft, acetylcholine binds to its receptors on the postsynaptic membrane, leading to the initiation of a signal in the neuron or muscle cell. This binding causes ion channels to open, resulting in depolarization and the subsequent transmission of nerve impulses. The correct answer highlights its role in stimulating continuous signaling. Acetylcholine's action is not just limited to short bursts of activity; it can lead to sustained stimulation of the postsynaptic neuron or muscle cell as long as it remains bound to its receptors and is not broken down by the enzyme acetylcholinesterase. In contrast, the other options refer to effects that are not aligned with acetylcholine's primary function in the synapse. For example, while acetylcholine can have inhibitory effects in certain situations or in specific pathways (such as in the heart where it can decrease heart rate), it generally promotes excitatory signals in muscle contraction and neuron activation. Similarly, it does not prevent muscle contraction, as its primary role is to facilitate muscle movement. Lastly, acetylcholine