In the structure of a skeletal muscle fiber, the plasma membrane of the muscle fiber is called the:

• A. Endomysium
• B. Myofibril
• C. Sarcolemma
• D. Sarcoplasmic reticulum

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the components of a skeletal muscle fiber. A skeletal muscle fiber is a single muscle cell, and it has several key structures including the plasma membrane, cytoplasm, and specialized organelles.
2. Step 2: Identify the term for the plasma membrane of a muscle fiber. In muscle physiology, the plasma membrane surrounding each muscle fiber is specifically called the sarcolemma.
3. Step 3: Differentiate the sarcolemma from other terms: the endomysium is connective tissue surrounding individual muscle fibers, the myofibril is a contractile element inside the muscle fiber, and the sarcoplasmic reticulum is a specialized endoplasmic reticulum involved in calcium storage.
4. Step 4: Recognize that the sarcolemma functions as the barrier between the extracellular environment and the interior of the muscle fiber, playing a crucial role in conducting electrical signals for muscle contraction.
5. Step 5: Conclude that the correct term for the plasma membrane of a skeletal muscle fiber is the sarcolemma, distinguishing it from other structural components.