Preganglionic sympathetic fibres are generally___________than postganlionic sympathetic fibres while preganglionic parasympathetic fibres while preganglionic parasympathetic fibres are ____than postganglionic parasympathetic fibres.

Answer

To answer the question regarding the lengths of preganglionic and postganglionic fibers in the sympathetic and parasympathetic nervous systems, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Sympathetic and Parasympathetic Fibers**:
- The sympathetic and parasympathetic nervous systems are components of the autonomic nervous system, which controls involuntary bodily functions.
- Sympathetic fibers are involved in the 'fight or flight' response, while parasympathetic fibers are involved in 'rest and digest' activities.

2. **Identifying Preganglionic and Postganglionic Fibers**:
- Preganglionic fibers are the nerve fibers that originate from the central nervous system (CNS) and synapse at ganglia.
- Postganglionic fibers are those that extend from the ganglia to the target organs.

3. **Analyzing Sympathetic Fibers**:
- Preganglionic sympathetic fibers are generally **shorter** than postganglionic sympathetic fibers. This is because the ganglia of the sympathetic nervous system are located relatively far from the target organs, leading to longer postganglionic fibers.

4. **Analyzing Parasympathetic Fibers**:
- Preganglionic parasympathetic fibers are generally **longer** than postganglionic parasympathetic fibers. This is due to the fact that the ganglia of the parasympathetic nervous system are located close to or within the target organs, resulting in shorter postganglionic fibers.

5. **Final Answer**:
- Therefore, the complete answer to the question is:
- Preganglionic sympathetic fibers are generally **shorter** than postganglionic sympathetic fibers, while preganglionic parasympathetic fibers are **longer** than postganglionic parasympathetic fibers.