Lack of relaxation between successive stimuli in sustained muscle contraction is known as

Options

A. Tonus
B. Spasm
C. Fatigue
D. Tetanus.

Answer

To answer the question regarding the lack of relaxation between successive stimuli in sustained muscle contraction, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Muscle Contraction**: Muscle contraction occurs when muscle fibers shorten and generate force. This process is initiated by stimuli from the nervous system.

2. **Types of Muscle Contraction**: There are different types of muscle contractions, including:
- **Tonus**: A state of low-level muscle activity or tension.
- **Spasm**: An involuntary and sudden muscle contraction that can be painful and is often uncontrollable.
- **Fatigue**: A condition where muscles lose their ability to contract due to prolonged activity.

3. **Identifying the Key Concept**: The question specifically asks about the lack of relaxation between successive stimuli. This means that the muscle is continuously contracted without returning to its resting state.

4. **Analyzing the Options**:
- **Tonus**: Refers to a low-level contraction, not a lack of relaxation.
- **Spasm**: Involves sudden and involuntary contractions, but does not specifically refer to sustained contraction.
- **Fatigue**: Refers to the inability of muscles to contract effectively after prolonged use, but does not directly describe sustained contraction.
- **Deadness**: This term can imply a state where there is no activity or contraction, which does not fit the description.

5. **Correct Answer**: The correct term that describes the lack of relaxation between successive stimuli leading to sustained muscle contraction is **"Tetanus"**. However, since "deadness" was mentioned in the video transcript as the answer, it seems there may have been a misunderstanding. The correct term for sustained muscle contraction due to repeated stimuli is indeed **Tetanus**.

### Final Answer:
The lack of relaxation between successive stimuli in sustained muscle contraction is known as **Tetanus**.

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