Cardiac muscle is structurally different from
Smooth muscle because it

Options

A. is branched
B. is involuntary
C. has a single nucleus
D. does not fatigue.

Answer

**Step-by-Step Solution:**

1. **Identify the Types of Muscles:**
- There are three types of muscle tissues in the human body: skeletal muscle, smooth muscle, and cardiac muscle.

2. **Define Cardiac Muscle:**
- Cardiac muscle is the muscle tissue found in the heart. It is responsible for pumping blood throughout the cardiovascular system.

3. **Define Smooth Muscle:**
- Smooth muscle is found in various internal structures such as the digestive tract, uterus, and blood vessels. It is responsible for involuntary movements in these organs.

4. **Compare Structural Features:**
- **Cardiac Muscle:**
- Cardiac muscle fibers are branched and interconnected. They have intercalated discs that allow for synchronized contractions.
- Cardiac muscle cells typically have a single nucleus.
- **Smooth Muscle:**
- Smooth muscle fibers are non-striated, tapering at both ends, and do not have branching.
- Smooth muscle cells also have a single nucleus.

5. **Analyze the Given Options:**
- **Branched:** Cardiac muscle is branched, while smooth muscle is not. This is a distinguishing feature.
- **Involuntary:** Both cardiac and smooth muscles are involuntary, meaning they cannot be controlled consciously.
- **Single Nucleus:** Both types of muscle have a single nucleus in their cells, so this does not differentiate them.
- **Does Not Fatigue:** Both cardiac and smooth muscle can be considered to not fatigue in the same way as skeletal muscle, so this does not differentiate them either.

6. **Conclusion:**
- The structural difference between cardiac muscle and smooth muscle is that cardiac muscle is branched, while smooth muscle is not.

**Final Answer:**
Cardiac muscle is structurally different from smooth muscle because it is branched.

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