Heat muscle is sensitive to

Options

A. Electrical stimuli
B. Chemical stimuli
C. Mechanical stimuli
D. All the above.

Answer

**Step-by-Step Solution:**

1. **Identify the Type of Muscle**: The question specifically refers to "heat muscle," which is commonly understood as cardiac muscle or heart muscle.

2. **Understand Muscle Types**: There are three major types of muscles in the human body:
- Skeletal muscles (voluntary)
- Smooth muscles (involuntary)
- Cardiac muscles (involuntary)

3. **Focus on Cardiac Muscle**: Since the question is about heart muscle, we focus on cardiac muscle, which is responsible for pumping blood throughout the body.

4. **Determine Sensitivity**: Cardiac muscles are known to respond to various types of stimuli:
- **Electrical Stimuli**: Cardiac muscles respond to electrical impulses that regulate heartbeats.
- **Chemical Stimuli**: These include hormones and drugs that can affect heart function.
- **Mechanical Stimuli**: Physical changes such as stretching or pressure can also influence cardiac muscle activity.

5. **Conclude the Answer**: Since cardiac muscles are sensitive to electrical, chemical, and mechanical stimuli, the correct answer is "all the above."

**Final Answer**: Heart muscle (cardiac muscle) is sensitive to all the above stimuli: electrical, chemical, and mechanical.

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