Consider the following characteristics wrt ANS. (a) Cranio-sacral outflow.br (b) Post ganglionic nerve fibres are shorter than preganglionic nerve fibres. br (c) Has adrenergic post ganglionic fibres. br (d) Has collateral ganglia situated in abdominal cavity. How many among the above mentioned characteristics describe the parasympathetic nervous system?

Options

A. 1
B. 3
C. 4
D. 2

Answer

To solve the question regarding the characteristics of the parasympathetic nervous system, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyze Statement (a): Cranio-sacral outflow.**
- The parasympathetic nervous system is known for its cranio-sacral outflow, which means it originates from the brain (cranial nerves) and sacral region (S2 to S4) of the spinal cord.
- **Conclusion:** This statement is **true** for the parasympathetic nervous system.

2. **Analyze Statement (b): Postganglionic nerve fibers are shorter than preganglionic nerve fibers.**
- In the parasympathetic nervous system, the preganglionic fibers are long because they extend from the central nervous system to the ganglia, which are located close to or within the target organs. The postganglionic fibers are shorter as they extend from the ganglia to the target tissues.
- **Conclusion:** This statement is **true** for the parasympathetic nervous system.

3. **Analyze Statement (c): Has adrenergic postganglionic fibers.**
- The postganglionic fibers of the parasympathetic nervous system are cholinergic, meaning they release acetylcholine as a neurotransmitter. In contrast, adrenergic fibers release norepinephrine and are characteristic of the sympathetic nervous system.
- **Conclusion:** This statement is **false** for the parasympathetic nervous system.

4. **Analyze Statement (d): Has collateral ganglia situated in the abdominal cavity.**
- Collateral ganglia are associated with the sympathetic nervous system, not the parasympathetic nervous system. The parasympathetic system does not have collateral ganglia; instead, its ganglia are located near or within the target organs.
- **Conclusion:** This statement is **false** for the parasympathetic nervous system.

### Final Count of True Statements:
- From the analysis, we found that statements (a) and (b) are true, while statements (c) and (d) are false. Therefore, **2 statements** describe the parasympathetic nervous system.

### Answer:
The number of characteristics that describe the parasympathetic nervous system is **2**.

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