Which of the following options correctly describes the sequence of structures present between a receptor and an effector when D refers dendrite, A refers axon, S refers synapse and CB refers to cell body ?

Options

A. D-CB-A-S-D-CB-A
B. A-D-CB-S-A-D-CB
C. D-CB-A-S-A-CB-D
D. D-A-S-CB-D-A-CB

Explanation

To determine the correct sequence of structures present between a receptor and an effector in a neuron, we can break down the process step by step.

### Step-by-Step Solution:

1. **Identify the Receptor**:
- The receptor in a neuron is typically located on the dendrites. Dendrites receive signals from other neurons or stimuli, making them the first point of contact in the neural pathway.
- **Hint**: Remember that dendrites are responsible for receiving information.

2. **Signal Transmission to Cell Body**:
- After the dendrites receive the signal, the nerve impulse travels to the cell body (CB). The cell body processes the incoming signals.
- **Hint**: Think of the cell body as the control center of the neuron.

3. **Traveling Along the Axon**:
- From the cell body, the impulse moves down the axon (A). The axon is responsible for transmitting the impulse away from the cell body towards the next neuron or effector.
- **Hint**: The axon acts like a highway for the nerve impulse.

4. **Reaching the Nerve Ending**:
- The impulse then reaches the nerve endings, where it prepares to transmit the signal to the next neuron or effector.
- **Hint**: Nerve endings are crucial for passing on the signal.

5. **Crossing the Synapse**:
- The signal crosses the synapse (S), which is the gap between two neurons. Neurotransmitters are released here to facilitate communication between neurons.
- **Hint**: The synapse is the bridge between two neurons.

6. **Continuing the Process**:
- After crossing the synapse, the signal reaches the dendrites of the next neuron, and the process repeats: dendrites (D), cell body (CB), axon (A), and synapse (S).
- **Hint**: This cycle continues as long as signals need to be transmitted.

### Final Sequence:
Putting it all together, the sequence of structures from receptor to effector is:
- Dendrite (D) → Cell Body (CB) → Axon (A) → Synapse (S) → Dendrite (D) of the next neuron.

Thus, the correct option that describes this sequence is:
**D → CB → A → S → D**.

### Answer:
The correct sequence is **D, CB, A, S**.