SLCC Exam 3 UPDATED ACTUAL
Questions and CORRECT Answers
Sarcolemma - CORRECT ANSWER - plasma membrane of a muscle fiber
sarcoplasmic reticulum - CORRECT ANSWER - stores calcium,smooth ER
Myofibrils - CORRECT ANSWER - Microscopic protein filaments that make up muscle
cells.
T tubules - CORRECT ANSWER - - Carry AP deep into the inner SR
Also called transverse tubules, these are deep invaginations of the plasma membrane found in
skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to
quickly penetrate to the interior of the cell.
A-band - CORRECT ANSWER - Full length of myosin
I band - CORRECT ANSWER - only actin
Z line - CORRECT ANSWER - A dark thin protein band to which actin filaments are
attached in a striated muscle fiber, marking the boundaries between adjacent sarcomeres.
H zone - CORRECT ANSWER - only myosin
Titian - CORRECT ANSWER - Provides structural support
termination of contraction - CORRECT ANSWER - Ca2+ must leave troponin, allowing
tropomyosin to cover myosin binding sites on actin
To remove Ca2+ from cytosol
, Ca2+-ATPase in the sarcoplasmic reticulum
Transports Ca2+ from cytosol into the sarcoplasmic reticulum
isotonic twitch - CORRECT ANSWER - a twitch during which a muscle shortens and lifts
a constant load
Tension - CORRECT ANSWER - Produced by each fiber
Isometric twitch - CORRECT ANSWER - A twitch during which a muscle generates for
but does not shorten
Best tension - CORRECT ANSWER - Right in the middle w/ the cross bridges
motor unit - CORRECT ANSWER - a motor neuron and all the muscle cells it stimulates
recruitment - CORRECT ANSWER - stimulus is sent to more muscle fibers, leading to
more precise control
Slow oxidation fibers - CORRECT ANSWER - Appear dark red because they contain
large amounts of myoglobin and many blood capillaries. Generate ATP mainly by aerobic
respiration
fast oxidative fibers - CORRECT ANSWER - contract quickly, have fast myosin ATPases,
and have moderate resistance to fatigue, Aerobic
fast glycolytic fibers - CORRECT ANSWER - Important for short-term intense, powerful
movements. Prefer glycolysis to make atp
muscle spindles - CORRECT ANSWER - receptors sensitive to change in length of the
muscle and the rate of that change
Questions and CORRECT Answers
Sarcolemma - CORRECT ANSWER - plasma membrane of a muscle fiber
sarcoplasmic reticulum - CORRECT ANSWER - stores calcium,smooth ER
Myofibrils - CORRECT ANSWER - Microscopic protein filaments that make up muscle
cells.
T tubules - CORRECT ANSWER - - Carry AP deep into the inner SR
Also called transverse tubules, these are deep invaginations of the plasma membrane found in
skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to
quickly penetrate to the interior of the cell.
A-band - CORRECT ANSWER - Full length of myosin
I band - CORRECT ANSWER - only actin
Z line - CORRECT ANSWER - A dark thin protein band to which actin filaments are
attached in a striated muscle fiber, marking the boundaries between adjacent sarcomeres.
H zone - CORRECT ANSWER - only myosin
Titian - CORRECT ANSWER - Provides structural support
termination of contraction - CORRECT ANSWER - Ca2+ must leave troponin, allowing
tropomyosin to cover myosin binding sites on actin
To remove Ca2+ from cytosol
, Ca2+-ATPase in the sarcoplasmic reticulum
Transports Ca2+ from cytosol into the sarcoplasmic reticulum
isotonic twitch - CORRECT ANSWER - a twitch during which a muscle shortens and lifts
a constant load
Tension - CORRECT ANSWER - Produced by each fiber
Isometric twitch - CORRECT ANSWER - A twitch during which a muscle generates for
but does not shorten
Best tension - CORRECT ANSWER - Right in the middle w/ the cross bridges
motor unit - CORRECT ANSWER - a motor neuron and all the muscle cells it stimulates
recruitment - CORRECT ANSWER - stimulus is sent to more muscle fibers, leading to
more precise control
Slow oxidation fibers - CORRECT ANSWER - Appear dark red because they contain
large amounts of myoglobin and many blood capillaries. Generate ATP mainly by aerobic
respiration
fast oxidative fibers - CORRECT ANSWER - contract quickly, have fast myosin ATPases,
and have moderate resistance to fatigue, Aerobic
fast glycolytic fibers - CORRECT ANSWER - Important for short-term intense, powerful
movements. Prefer glycolysis to make atp
muscle spindles - CORRECT ANSWER - receptors sensitive to change in length of the
muscle and the rate of that change
