Muscular system practice test
How many ATPs are produced from aerobic respiration of one glucose molecule?
38
Which of the following is NOT an event that occurs during the lag phase of a muscle twitch?
Acetylcholine diffuses across the synaptic cleft
Which of the following is also known as the thin myofilament?
Actin
The A band is made up of
Actin and myosin
Which of the following is NOT involved in the process of muscle relaxation?
All of the above occur during relaxation
The ability of muscle to recoil to its resting length after being stretched is
Elasticity
What type of connective tissue surrounds individual muscle fibers?
Endomysium
What type of connective tissue surrounds individual muscles?
Epimysium
The ability of muscle to respond to a stimulus is
Excitability
The mechanism by which an action potential in the sarcolemma causes a muscle contraction is called
Excitation-contraction coupling
The ability of muscle to contract when stretched beyond its normal resting length is
Extensibility
When is anaerobic respiration used by muscle cells?
For short periods of time of intense exercise
Which of the following is NOT an important voltage-gated ion channel on a muscle or nerve plasma membrane?
Magnesium
Which of the following is also known as the thick myofilament?
Myosin
Which of the following is true of smooth muscle?
Non-striated, spindle-shaped cells
What is released from the myosin head after the power stroke occurs?
Phosphate
What occurs during the process of repolarization?
Potassium gates open out of the cell making the outside more positive
Creatine phosphate is used to
Regenerate ATP from ADP
What is the plasma membrane of a muscle fiber called?
Sarcolemma
The structural and functional unit of skeletal muscle is the
Sarcomere
Myofibrils are formed from ____________ that are joined end to end.
Sarcomeres
Which of the following is NOT a source of ATP for muscle contraction?
Sarcoplasmic reticulum
Which of the following is NOT part of a neuromuscular junction?
Sarcoplasmic reticulum
The binding of acetylcholine to a ligand-gated channel will allow ____ to enter the muscle fiber.
Sodium ions
Extensions of the sarcolemma into the interior of the muscle fiber are called
T tubules
What is the direct cause of the release of calcium ions from the sarcoplasmic reticulum?
The action potential traveling into T tubules
The H zone is where
There is only myosin
What is the role of acetylcholinesterase?
To remove and breakdown acetylcholine from the channel receptor
Which of the following is NOT true of skeletal muscle?
Totally under involuntary control
A gradual increase in muscle tension in a muscle that has been resting is called
Treppe
Which molecule covers the active site on the G actin?
Tropomyosin
Which molecule has a binding site for calcium?
Troponin
For how long does creatine phosphate provide ATP for contraction?
Up to 10 seconds
For how long does anaerobic respiration provide ATP for contraction?
Up to 3 minutes
What ion is necessary for the release of acetylcholine from the synaptic vesicles?
calcium
The constant tension in muscles over a long period of time that allows you to hold up your head is called
muscle tone
A motor unit is a single motor neuron and all the muscle fibers its branches innervate.
true
A sarcomere extends from one Z disk to the next Z disk.
true
A threshold stimulus is the minimum stimulus that will produce an action potential.
true
All action potentials are exactly the same.
true
Cardiac muscle cells and some smooth muscle cells are autorhythmic.
true
Cardiac muscle cells are striated and involuntary.
true
During the sliding filament model of muscle contraction, the Z disks are moved closer together.
true
Multiple motor unit summation follows the graded response principle of a muscle organ.
true
The arrangement of the myofilaments of the sarcomere create the striated appearance of skeletal muscle.
true
The greater the number of motor units that respond to a stimulus, the greater the tension of the muscle.
true
Voltage changes at one part of a plasma membrane will initiate voltage changes at adjacent parts of the membrane for the action potential to propagate.
true
By what process does acetylcholine move to the postsynaptic membrane?
diffusion
During the sliding filament model of muscle contraction the A band shortens.
false
During the sliding filament model of muscle contraction, the H zone gets larger.
false
Smooth muscles are instrumental in the process of respiration.
false
The all-or-none principle states that all motor neurons to a muscle will produce action potentials or none of them will.
false
Whole muscles respond to stimuli according to the all-or-none principle.
false
What is the main source of ATP production in skeletal muscle for sustained exercise and during rest?
glucose
Tightening your leg muscles while sitting in an airplane would be an example of a(an) ______________ contraction.
isometric
How many ATPs are produced from one glucose during anaerobic respiration?
2
The I band is made up of
A Z disk and actin
Which type of muscle is needed for propelling blood throughout the body?
Cardiac
What is it called when action potentials come so fast that the muscle fiber does not relax between them?
Complete tetanus
Which of the following is NOT a function of skeletal muscle?
Constriction of organs
Which of the following is a function of smooth muscle?
Constriction of organs and vessels
The ability of muscle to shorten forcefully is
Contractility
Which of the following is NOT a phase of a muscle twitch?
Interphase
What waste product is produced during anaerobic respiration?
Lactic Acid
What type of gated ion channel responds to a molecule binding to a receptor on the ion channel?
Ligand-gated ion channel
Which statement is true of a resting membrane potential?
The plasma membrane is positive on the outside with more sodium ions outside
What kind of gated ion channel responds to small changes in voltages across the plasma membrane?
Voltage-gated ion channel
What occurs during the process of depolarization?
odium gates open into the cell making the inside more positive
