Which of the following structures is responsible for releasing neurotransmitters at a chemical synapse?

• A. Presynaptic terminal
• B. Synaptic cleft
• C. Postsynaptic membrane
• D. Myelin sheath

Answer: (A)

Verified step by step guidance

1. Understand the structure of a chemical synapse: A chemical synapse is a junction between two neurons where neurotransmitters are released to transmit signals. It consists of three main components: the presynaptic terminal, synaptic cleft, and postsynaptic membrane.
2. Define the presynaptic terminal: The presynaptic terminal is the end of the axon of the sending neuron. It contains synaptic vesicles filled with neurotransmitters, which are released into the synaptic cleft during signal transmission.
3. Explain the role of the synaptic cleft: The synaptic cleft is the small gap between the presynaptic terminal and the postsynaptic membrane. Neurotransmitters travel across this gap to reach the postsynaptic membrane.
4. Describe the postsynaptic membrane: The postsynaptic membrane is part of the receiving neuron. It contains receptor proteins that bind to neurotransmitters, triggering a response in the receiving neuron.
5. Clarify the role of the myelin sheath: The myelin sheath is a fatty layer that insulates axons and speeds up signal transmission along the axon. It is not directly involved in neurotransmitter release at the synapse.