Alcohol affects mental and motor functions because

Options

A. It causes degeneration of contractile fibres of muscles
B. It crosses blood-brain barrier
C. It is quickly absorbed in gut
D. It raises blood pressure

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks why alcohol affects mental and motor functions. To answer this, we need to explore how alcohol interacts with the body, particularly the brain.

2. **Identifying Key Concepts**:
- Alcohol is a substance that can influence various bodily functions.
- Mental functions refer to cognitive processes such as thinking, memory, and decision-making.
- Motor functions refer to physical actions and coordination.

3. **Mechanism of Action**:
- Alcohol is absorbed quickly into the bloodstream after consumption.
- Once in the bloodstream, it circulates throughout the body, including the brain.

4. **Blood-Brain Barrier**:
- The blood-brain barrier is a protective barrier that regulates what substances can enter the brain from the bloodstream.
- Alcohol can cross this barrier, which is significant because it allows alcohol to directly affect brain cells.

5. **Effects on Brain Cells**:
- When alcohol crosses the blood-brain barrier, it can impair the functioning of brain cells.
- This impairment can lead to a decrease in cognitive abilities (mental functions) and coordination (motor functions).

6. **Conclusion**:
- Therefore, the reason alcohol affects mental and motor functions is that it crosses the blood-brain barrier and impacts the brain's ability to control behavior and physical actions.

**Final Answer**: Alcohol affects mental and motor functions because it crosses the blood-brain barrier.

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