Chapter 12 - Muscle Physiology Exam d d d d d d
Questions With 100% Accurate Answers d d d d
Sarcolemma - d d
The fine transparent tubular sheath that envelops the fibers of skeletal muscles
d d d d d d d d d d d d d d d d d d d d
Myofibrils - d d
Any of the elongated contractile threads found in striated muscle cells
d d d d d d d d d d d d d d d d d d d
Sarcoplasmic reticulum - d d d
The endoplasmic reticulum of cardiac muscle and skeletal striated muscle that functions
d d d d d d d d d d d d d d d d d d d d
especially as a storage and release area for calcium.
d d d d d d d d d
Transverse Tubules (T Tubule) - d d d d d
Any of the small tubules which run transversely through a striated muscle fiber and
d d d d d d d d d d d d d d d d d d d d d d d
through which electrical impulses are transmitted from the sarcoplasm to the fiber's interior
d d d d d d d d d d d d
Thick Filaments - d d d
A myofilament of one of the two types making up myofibrils that is 10 to 12
d d d d d d d d d d d d d d d d d d d d d d d d d
nanometers in width and is composed of the protein myosin. d d d d d d d d d
Thin Filaments - d d d
A myofilament of the one of the two types making up myofibrils that is about 5
d d d d d d d d d d d d d d d d d d d d d d d d d
nanometers in width and is composed chiefly of the protein actin. d d d d d d d d d d
Sarcomere - d d
A structural unit of a myofibril in striated muscle, consisting of a dark band and the
d d d d d d d d d d d d d d d d d d d d d d d d d
nearer half of each adjacent pale band.
d d d d d d
A Band -d d d
The area between two I bands of a sarcomere, marked by partial overlapping of actin
d d d d d d d d d d d d d d d d d d d d d d d d
and myosin filaments and appearing dark
d d d d d
H Zone -d d d
a narrow and less dense zone of myosin filaments disecting the A band in striated
d d d d d d d d d d d d d d d d d d d d d d d d
muscle
I Band -
d d d
The band within a striated myofibril, seen as a light region under the light microscope
d d d d d d d d d d d d d d d d d d d d d d d d
and as a dark region under polarized light.
d d d d d d d
Z line -d d d
Any of the dark bands across a striated muscle fiber that mark the junction of actin
d d d d d d d d d d d d d d d d d d d d d d d d d
filaments in adjacent sarcomeres d d d
M line - d d d
A thin dark line across the center of the H zone of a striated muscle fiber
d d d d d d d d d d d d d d d d d d d d d d d d
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, Actin - d d
A protein found especially in microfilaments (as those comprising myofibrils) and
d d d d d d d d d d d d d d d d d d d d
active in muscular contraction, cellular movement, and maintenance of cell shape
d d d d d d d d d d
Myosin - d d
A fibrous globulin of muscle that can split ATP and that reacts with actin to form
d d d d d d d d d d d d d d d d d d d d d d d d d
actomyosin
Tropomyosin - d d
A protein of muscle that forms a complex with troponin regulating the interaction of
d d d d d d d d d d d d d d d d d d d d d d d
actin and myosin in muscular contraction
d d d d d
Troponin - d d
A protein of muscle that together with tropomyosin forms a regulatory protein complex
d d d d d d d d d d d d d d d d d d d d d d
controlling the interaction of actin and myosin and that when combined with calcium ions
d d d d d d d d d d d d d d
permits muscular contraction d d
Crossbridges - d d
The globular head of a myosin molecule that projects from a myosin filament in muscle
d d d d d d d d d d d d d d d d d d d d d d d d
and in the sliding filament hypothesis of muscle contraction is held to attach temporarily to
d d d d d d d d d d d d d d d
an adjacent actin filament and draw it into the A band of a sarcomere between the myosin
d d d d d d d d d d d d d d d d d
filaments
Actin-binding Site - d d d
A protein found in all eukaryotic cells, forming filaments that make up a main
d d d d d d d d d d d d d d d d d d d d d d d
component of the cell's supporting matrix or cytoskeleton. Actin and the protein myosin
d d d d d d d d d d d d d
together make up the contractile units (called sarcomeres) of skeletal muscle fibers.
d d d d d d d d d d d
ATPase site - d d d
A class of enzymes that catalyze the decomposition of ATP into ADP
d d d d d d d d d d d d d d d d d d d d
Titin - d d
A very large fibrous protein that connects thick myosin filaments to Z discs in the
d d d d d d d d d d d d d d d d d d d d d d d d
sarcomere.
Sliding-filament Model - d d d
A proposed mechanism of muscle contraction in which the actin and myosin filaments
d d d d d d d d d d d d d d d d d d d d d d
of striated muscle slide over each other to shorten the length of the muscle fibres
d d d d d d d d d d d d d d
Crossbridge cycle - d d d
Forms the basis for movement and force production in muscle cells. Each cycle of
d d d d d d d d d d d d d d d d d d d d d d d
myosin binding to actin and movement of the thin filament involves the hydrolysis of one
d d d d d d d d d d d d d d d
ATP molecule. d
5 steps of crossbridge cycle -
d d d d d d
1. Binding of myosin to actin
d d d d d d d d d d d d d d
2. Power stroke
d d
3. Rigord
4. Unbinding of myosin and actin
d d d d d
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Questions With 100% Accurate Answers d d d d
Sarcolemma - d d
The fine transparent tubular sheath that envelops the fibers of skeletal muscles
d d d d d d d d d d d d d d d d d d d d
Myofibrils - d d
Any of the elongated contractile threads found in striated muscle cells
d d d d d d d d d d d d d d d d d d d
Sarcoplasmic reticulum - d d d
The endoplasmic reticulum of cardiac muscle and skeletal striated muscle that functions
d d d d d d d d d d d d d d d d d d d d
especially as a storage and release area for calcium.
d d d d d d d d d
Transverse Tubules (T Tubule) - d d d d d
Any of the small tubules which run transversely through a striated muscle fiber and
d d d d d d d d d d d d d d d d d d d d d d d
through which electrical impulses are transmitted from the sarcoplasm to the fiber's interior
d d d d d d d d d d d d
Thick Filaments - d d d
A myofilament of one of the two types making up myofibrils that is 10 to 12
d d d d d d d d d d d d d d d d d d d d d d d d d
nanometers in width and is composed of the protein myosin. d d d d d d d d d
Thin Filaments - d d d
A myofilament of the one of the two types making up myofibrils that is about 5
d d d d d d d d d d d d d d d d d d d d d d d d d
nanometers in width and is composed chiefly of the protein actin. d d d d d d d d d d
Sarcomere - d d
A structural unit of a myofibril in striated muscle, consisting of a dark band and the
d d d d d d d d d d d d d d d d d d d d d d d d d
nearer half of each adjacent pale band.
d d d d d d
A Band -d d d
The area between two I bands of a sarcomere, marked by partial overlapping of actin
d d d d d d d d d d d d d d d d d d d d d d d d
and myosin filaments and appearing dark
d d d d d
H Zone -d d d
a narrow and less dense zone of myosin filaments disecting the A band in striated
d d d d d d d d d d d d d d d d d d d d d d d d
muscle
I Band -
d d d
The band within a striated myofibril, seen as a light region under the light microscope
d d d d d d d d d d d d d d d d d d d d d d d d
and as a dark region under polarized light.
d d d d d d d
Z line -d d d
Any of the dark bands across a striated muscle fiber that mark the junction of actin
d d d d d d d d d d d d d d d d d d d d d d d d d
filaments in adjacent sarcomeres d d d
M line - d d d
A thin dark line across the center of the H zone of a striated muscle fiber
d d d d d d d d d d d d d d d d d d d d d d d d
1|Page
, Actin - d d
A protein found especially in microfilaments (as those comprising myofibrils) and
d d d d d d d d d d d d d d d d d d d d
active in muscular contraction, cellular movement, and maintenance of cell shape
d d d d d d d d d d
Myosin - d d
A fibrous globulin of muscle that can split ATP and that reacts with actin to form
d d d d d d d d d d d d d d d d d d d d d d d d d
actomyosin
Tropomyosin - d d
A protein of muscle that forms a complex with troponin regulating the interaction of
d d d d d d d d d d d d d d d d d d d d d d d
actin and myosin in muscular contraction
d d d d d
Troponin - d d
A protein of muscle that together with tropomyosin forms a regulatory protein complex
d d d d d d d d d d d d d d d d d d d d d d
controlling the interaction of actin and myosin and that when combined with calcium ions
d d d d d d d d d d d d d d
permits muscular contraction d d
Crossbridges - d d
The globular head of a myosin molecule that projects from a myosin filament in muscle
d d d d d d d d d d d d d d d d d d d d d d d d
and in the sliding filament hypothesis of muscle contraction is held to attach temporarily to
d d d d d d d d d d d d d d d
an adjacent actin filament and draw it into the A band of a sarcomere between the myosin
d d d d d d d d d d d d d d d d d
filaments
Actin-binding Site - d d d
A protein found in all eukaryotic cells, forming filaments that make up a main
d d d d d d d d d d d d d d d d d d d d d d d
component of the cell's supporting matrix or cytoskeleton. Actin and the protein myosin
d d d d d d d d d d d d d
together make up the contractile units (called sarcomeres) of skeletal muscle fibers.
d d d d d d d d d d d
ATPase site - d d d
A class of enzymes that catalyze the decomposition of ATP into ADP
d d d d d d d d d d d d d d d d d d d d
Titin - d d
A very large fibrous protein that connects thick myosin filaments to Z discs in the
d d d d d d d d d d d d d d d d d d d d d d d d
sarcomere.
Sliding-filament Model - d d d
A proposed mechanism of muscle contraction in which the actin and myosin filaments
d d d d d d d d d d d d d d d d d d d d d d
of striated muscle slide over each other to shorten the length of the muscle fibres
d d d d d d d d d d d d d d
Crossbridge cycle - d d d
Forms the basis for movement and force production in muscle cells. Each cycle of
d d d d d d d d d d d d d d d d d d d d d d d
myosin binding to actin and movement of the thin filament involves the hydrolysis of one
d d d d d d d d d d d d d d d
ATP molecule. d
5 steps of crossbridge cycle -
d d d d d d
1. Binding of myosin to actin
d d d d d d d d d d d d d d
2. Power stroke
d d
3. Rigord
4. Unbinding of myosin and actin
d d d d d
2|Page
