BMS unit 4
All the muscle fibers under the control of a single motor axon are referred to as
a motor unit
all of these proteins are thin filaments:
actin troponin tropomyosin
A skeletal muscle fiber (cell) contains a single nucleus. true or false
false
Which of the following statements is true concerning calcium ions?
in smooth. muscle, it binds with calmodulin
Which of the following best describes the role of Ca2+ in muscle contraction?
it binds to troponin , moving tropomyosin, so that myosin heads can bind to actin
The typical skeletal muscle fiber contains several components that facilitate the production of ATP. what are they
mitochondria myoglobin glycogen
Place the organizational level of muscle tissue in order, beginning with the entire muscle and ending with the smallest component.
muscle fascicle muscle fiber myofibril myofilaments
thick filaments have
myosin and myosin heads
The amount of additional oxygen that must be inhaled following exercise to restore pre-exercise conditions is called
oxygen debt
the muscle cell membrane is called
sarcolemma
The contractile unit of a myofibril is called the
sarcomere
An action potential causes calcium ions to diffuse from the ________ into the ________.
sarcoplasmic reticulum ; sarcoplasm
At the ends of muscles, the connective tissues merge to form a __________, which attaches the muscle to other structures.
tendon
The specialized region of the sarcolemma that has folds and indentations to increase the membrane surface area covered by the synaptic knob is the
the motor end plate
The component of a muscle fiber that quickly transports a muscle impulse from the sarcolemma throughout the entire muscle fiber is called the
transverse tubules
Rising sarcoplasmic calcium levels results in contraction in both smooth muscle fibers and skeletal muscle fibers. true or false
true
Smooth muscle contraction and skeletal muscle contraction both involve thin filaments sliding over the thick filaments. true or false
true
The area between the presynaptic nerve cell and the postsynaptic muscle cell is termed the synaptic cleft. True or False?
true
A ________ is defined as a single, brief contraction period and then relaxation period of a skeletal muscle in response to a single stimulation.
twitch
