Which of the following statements is incorrect ?

Options

A. Smooth muscle are found in urinary bladdedr, alimentary canal and genital tract.
B. A striated muscle is a syncytium i.e., a multinucleate structure.
C. The cytoplasm of striated muscle is called endoplasm.
D. The plasma membrane and ER of striated muscles are called sarcoplasmic reticulum respectively.

Explanation

To determine which statement is incorrect regarding muscle fibers, let's analyze each statement step by step:

1. **Statement A**: "Smooth muscles are found in the urinary bladder, elementary canal, and genital tract."
- This statement is correct. Smooth muscles, also known as visceral muscles, are indeed found in various internal organs, including the urinary bladder, the gastrointestinal tract (elementary canal), and the genital tract.

2. **Statement B**: "Striated muscle is a syncytium means a multinucleate structure."
- This statement is incorrect. Striated muscles (skeletal muscles) are not syncytial; they are made up of individual muscle fibers that are multinucleated but do not form a single multinucleate structure. Each muscle fiber is distinct and not a syncytium.

3. **Statement C**: "Cytoplasm of striated muscle is called endoplasm."
- This statement is incorrect. The cytoplasm of striated muscle (skeletal muscle) is known as sarcoplasm, not endoplasm. Endoplasm is a term that is not typically used in the context of muscle fibers.

4. **Statement D**: "The plasma membrane and endoplasmic reticulum of striated muscle are called sarcoplasmic reticulum."
- This statement is correct. The plasma membrane of muscle fibers is referred to as the sarcolemma, and the specialized endoplasmic reticulum in muscle fibers is called the sarcoplasmic reticulum.

**Conclusion**: The incorrect statements are B and C. However, since the question asks for one incorrect statement, the most straightforward answer is **Statement C**: "Cytoplasm of striated muscle is called endoplasm."