Which of the following human parasympathetic function is not under the control of a cranial nerve?

Options

A. Contraction of bladder
B. Constriction of pupil
C. Increase of salivation
D. Stimulation of gall bladder activity

Explanation

To solve the question regarding which human parasympathetic function is not under the control of a cranial nerve, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Parasympathetic Nervous System**:
- The parasympathetic nervous system is part of the autonomic nervous system and is responsible for rest-and-digest activities. It is primarily controlled by cranial nerves and sacral spinal nerves.

2. **Identify the Functions of the Parasympathetic Nervous System**:
- Common functions include contraction of pupils (miosis), stimulation of salivation, stimulation of gallbladder activity, and contraction of the bladder.

3. **Cranial Nerves Involved**:
- The cranial nerves that are involved in parasympathetic functions include the oculomotor nerve (III), facial nerve (VII), glossopharyngeal nerve (IX), and vagus nerve (X).

4. **Evaluate Each Option**:
- **Contraction of pupils**: Controlled by the oculomotor nerve (III).
- **Stimulation of gallbladder activity**: Controlled by the vagus nerve (X).
- **Contraction of bladder**: This function is primarily controlled by the sacral spinal nerves, specifically through postganglionic fibers, rather than cranial nerves.

5. **Conclusion**:
- The contraction of the bladder is the parasympathetic function that is not under the control of a cranial nerve. It is regulated by postganglionic nerves that release acetylcholine to stimulate bladder contraction.

### Final Answer:
The correct answer is **contraction of the bladder**.

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