Muscle Intro 177-183
Which type of filament is anchored to the Z disc within a myofibril?
Thin filaments
Cardiac and skeletal muscle both possess striations.
True
Cardiac muscle fibers are joined by special gap junctions called intercalated discs; these discs allow heart activity to be closely coordinated.
True
The sarcoplasmic reticulum wraps like a sleeve around the myofibril and stores and releases calcium.
True
The striations seen in skeletal muscle are actually alternating dark A and light I bands.
True
Which of these increases as muscles age?
amount of connective tissue in a muscle
What is covered by the endomysium?
an individual muscle cell
Which of the following is not> a function of the muscular system?
blood cell formation
Striated involuntary muscle tissue is classified as ________ muscle.
cardiac
Striated involuntary muscle tissue found in the heart is ________.
cardiac muscle
What type of muscle tissue is both striated and involuntary?
cardiac muscle
The heads of the myosin myofilaments are called ________ when they link the thick and thin filaments together during skeletal muscle contraction.
cross bridges
Which layer of connective tissue surrounds each skeletal muscle fiber?
endomysium
Which of these characteristics applies only to cardiac muscle tissue?
intercalated discs
Which connective tissue bundles muscle fibers into fascicles?
perimysium
What can older individuals do to increase muscle strength?
regularly use hand weights and practice leg lifts
The plasma membrane of a skeletal muscle cell is called the ________.
sarcolemma
What organelle wraps and surrounds the myofibril and stores calcium?
sarcoplasmic reticulum
Which term does >not describe smooth muscle cells?
skeletal
The type of muscle tissue pictured in the figure is ________.
smooth muscle
A sarcomere is ________.
the contractile unit between two Z discs
Which of the following is composed mostly of the protein myosin?
thick filaments
What creates the alternating light and dark bands that provides the striation pattern on skeletal muscle tissue?
A bands and I bands
Smooth muscle cells produce movement of the body and generate heat.
False
The A band within a myofibril is indicated by ________
Label A
The epimysium is represented by ________.
Label A
The I band within a skeletal muscle fiber is indicated by ________.
Label B
The endomysium that wraps individual muscle fibers is indicated by ________.
Label B
The perimysium wraps a fascicle of muscle cells and is represented by ________.
Label C
The H zone, located within the A band, lacks thin filaments and is represented by ________.
Label D
The muscle fiber (cell) is indicated by ________.
Label D
Which organelle stores calcium in muscle fibers?
Sarcoplasmic reticulum
