All or none law is mot applicable for

Options

A. Single skeletal muscle fibre
B. Whole skeletal muscle
C. Single smooth muscle fibre
D. Whole cardiac muscle.

Answer

To answer the question "All or none law is not applicable for," we need to understand the concept of the all-or-none law in relation to muscle fibers. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the All-or-None Law
The all-or-none law states that a muscle fiber or a nerve will respond completely if the stimulus exceeds a certain threshold. If the stimulus is below this threshold, there will be no response at all.

### Step 2: Identify the Options
The options given are:
1. Single skeletal muscle fiber
2. Whole skeletal muscle
3. Single smooth muscle fiber
4. Whole cardiac muscle

### Step 3: Analyze Each Option
- **Single Skeletal Muscle Fiber**: The all-or-none law applies here. If the stimulus is strong enough, the fiber will contract fully.
- **Whole Skeletal Muscle**: The all-or-none law does not apply here because the whole muscle can have varying degrees of contraction based on the number of fibers activated.
- **Single Smooth Muscle Fiber**: The all-or-none law applies to individual smooth muscle fibers, similar to skeletal muscle fibers.
- **Whole Cardiac Muscle**: The all-or-none law applies to cardiac muscle fibers, but the whole cardiac muscle can exhibit varying degrees of contraction due to the nature of its function.

### Step 4: Conclusion
Based on the analysis, the all-or-none law is not applicable for the **whole skeletal muscle** because it can contract to varying degrees depending on the number of muscle fibers activated.

### Final Answer
The all-or-none law is not applicable for **whole skeletal muscle**.

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