Choose the correct Statement about the transmission of impulses.

Options

A. At electrical synapses , the membranes of pre-and-synaptic neurons , are situated for form each other .
B. The synaptic vesicles fuse with the plasma membrane and release their neurons are situated far from each other .
C. The released neurotransmitters bind to their specific receptors, present on the pre-synaptic membrane.
D. Impulse transmission across a chemical synapse is always faster than that across an electrical synapse.

Answer

To solve the question regarding the correct statement about the transmission of impulses, we will analyze each of the provided statements one by one.

### Step-by-Step Solution:

1. **Understanding Electrical Synapses**:
- The first statement claims that "At electrical synapses, the membranes of pre-synaptic neurons are situated far from each other."
- This statement is **incorrect** because electrical synapses involve direct connections between neurons through gap junctions, meaning the membranes are very close to each other.

**Hint**: Recall that electrical synapses allow direct ionic current flow between neurons.

2. **Synaptic Vesicle Function**:
- The second statement mentions that "the synaptic vesicle fused with plasma membrane and release neurotransmitters."
- This statement is **correct**. Synaptic vesicles, located at the end of the neuron, fuse with the plasma membrane to release neurotransmitters into the synaptic cleft.

**Hint**: Remember the role of synaptic vesicles in neurotransmitter release during synaptic transmission.

3. **Neurotransmitter Binding**:
- The third statement states that "the released neurotransmitter binds to the specific receptor present on the pre-synaptic membrane."
- This statement is **incorrect** because neurotransmitters bind to receptors on the **post-synaptic** membrane, not the pre-synaptic membrane.

**Hint**: Think about the direction of signal transmission in synapses.

4. **Speed of Impulse Transmission**:
- The fourth statement claims that "impulse transmission across a chemical synapse is always faster than that across an electrical synapse."
- This statement is **incorrect**. In fact, transmission across electrical synapses is generally faster than that across chemical synapses due to the direct connection between neurons.

**Hint**: Compare the mechanisms of electrical and chemical synapses regarding speed.

### Conclusion:
Based on the analysis of the statements, the **correct statement** about the transmission of impulses is the second one: "the synaptic vesicle fused with plasma membrane and release neurotransmitters."