Receptor sites for neurotransmitters are present on :

Options

A. Membranes of synaptic vesicles
B. Pre-synaptic membrane
C. Tips of axons
D. Post - synaptic membrane

Answer

**Step-by-Step Solution:**

1. **Understanding Neurons**: Neurons are the basic structural and functional units of the nervous system. They consist of three main parts: the cell body, dendrites, and axon.

2. **Role of Dendrites and Axon**: Dendrites are responsible for receiving stimuli, while the axon conducts nerve impulses away from the cell body.

3. **Transmission of Nerve Impulses**: Nerve impulses are transmitted from one neuron to another through junctions known as synapses.

4. **Structure of Synapse**: A synapse is formed by the membranes of the pre-synaptic neuron (the neuron sending the signal) and the post-synaptic neuron (the neuron receiving the signal).

5. **Synaptic Vesicles and Neurotransmitters**: In the terminal region of the axon of the pre-synaptic neuron, there are synaptic vesicles that contain neurotransmitters. When an impulse reaches this terminal region, the vesicles fuse with the membrane and release neurotransmitters into the synaptic cleft (the gap between the two neurons).

6. **Receptor Sites**: The post-synaptic membrane contains specific receptor sites for these neurotransmitters. When neurotransmitters are released into the synaptic cleft, they bind to these receptors, facilitating the transmission of the nerve impulse.

7. **Conclusion**: Therefore, the receptor sites for neurotransmitters are primarily located on the post-synaptic membrane.

**Final Answer**: Receptor sites for neurotransmitters are present on the post-synaptic membrane.

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