Open Question
The smooth muscle type found in the walls of digestive and urinary system organs and that exhibits gap junctions and pacemaker cells isa. multi unit,b. unitary.
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.
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