Multiple Choice
In skeletal muscle fibers, which structure serves as the primary intracellular storage site for calcium ions (Ca2+) used to trigger contraction?
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9. Muscle Tissue
Structure of a Skeletal Muscle
Multiple Choice
The plasma membrane of a muscle fiber is called the ____________ and it wraps bundles of ____________.
A
Sarcolemma: myofibrils.
B
Sarcoplasmic reticulum: myofilaments.
C
Sarcomere: myofilaments.
D
Sarcoplasmic reticulum: myofibrils.
Verified step by step guidance1
Understand the structure of a muscle fiber: A muscle fiber is a single muscle cell, and its plasma membrane is known as the sarcolemma.
Identify the components within the muscle fiber: Inside the muscle fiber, there are bundles of myofibrils, which are the contractile elements of the cell.
Differentiate between myofibrils and myofilaments: Myofibrils are composed of repeating units called sarcomeres, which contain the myofilaments actin and myosin.
Recognize the role of the sarcoplasmic reticulum: The sarcoplasmic reticulum is a specialized form of the endoplasmic reticulum in muscle cells, responsible for storing and releasing calcium ions, and it surrounds the myofibrils.
Match the terms correctly: The plasma membrane of a muscle fiber is the sarcolemma, and it wraps around bundles of myofibrils, not myofilaments.
