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Which of the following myofilaments makes up the thick filament?
What type of channel is found at the motor end plate of the muscle fiber?
Voltage-gated Na+ channel
Voltage-gated Ca2+ channel
Ligand-gated Na+ channel
Ligand-gated Ca2+ channel
Which of the following changes occurs within a muscle cell after resistance training?
An increase in the number of oxidative enzymes
An increase in the number of myofibrils
An increase in fatigue resistance
A decrease in the size of myofibrils
Select all that apply: These muscle cells are striated.
What kind of neuron is pictured?
Which of the following neurons will propagate an action potential the fastest?
A neuron with a small unmyelinated axon.
A neuron with a small myelinated axon.
A neuron with a large unmyelinated axon.
A neuron with a large myelinated axon.
What part of the sarcomere is letter "e" identifying?
The I band
The H zone
The A band
The Zone of Overlap
Which of the following processes of ATP generation does NOT take place in the cytosol?
Creatine phosphate hydolysis
Glycolysis (Anaerobic metabolism)
Oxidative metabolism (Aerobic metabolism)
All 3 processes take place within the cytosol.
Select all the apply: Which of the following could lead to hyperpolarization of the axolemma?
Opening of ligand-gated K+ channels
Opening of ligand-gated Na+ channels
Opening of ligand-gated Cl- channels
Opening of voltage-gated Na+ channels
When ___ binds to myosin, the myosin head detaches from actin.
Inorganic phosphate (Pi)
In this part of an action potential, the voltage-gated Na+ channels are ____ and the voltage-gated K+ channels are ______.
Which of the following is false about unfused tetanus?
It is a type of wave summation.
Tension can reach 100% of maximum.
The muscle fiber can partially relax between stimuli.
All three options are true.
Select all that apply: What occurs during skeletal muscle relaxation?
Ca2+ ions are pumped back into the sarcoplasmic reticulum.
Acetylcholinesterase breaks down the acetylcholine in the synaptic cleft.
Tropomyosin is moved off of the actin active sites.
The motor neuron stops firing action potentials.
Which of the following is false about neuron action potentials?
Action potentials are irreversible
Action potentials are initiated by local depolarizations
Action potentials are initiated at the axon hillock
The magnitude of an action potential decreases as it travels down the axon
When acetylcholine binds to ligand-gated Na+ channels at the motor end plate, Na+ _____ the muscle cell and an _______ potential is initiated.
enters; end plate
exits; end plate
True or False? A stimulus that surpasses threshold (B) will cause a larger action potential than a stimulus that just reaches threshold (A).
Saltatory conduction occurs in _______ whereas continuous conduction occurs in _________
Myelinated axons; unmyelinated axons
Unmyelinated axons; myelinated axons
Which of the following changes will happen in a sarcomere during a contraction?
Actin pulls myosin towards the M-line
The A band narrows
The I band narrows
All of the above
True or False? More than one muscle fiber can be innervated by the same motor neuron.
In _____ summation, simultaneous ____ from multiple neurons bring the trigger zone to threshold.
Which of the following neuroglial cell type makes up the myelin sheath in the peripheral nervous system?
Select all the apply: Where is there a high abundance of voltage-gated Ca2+ channels?
In the axon terminal
In the motor end plate
In the muscle fiber sarcolemma
At the sarcoplasmic reticulum
When Erica pets her cat, Cleo, she can feel that she is very soft. Which nervous system division is responsible for sending this information from Erica's fingertips to her brain?
The visceral sensory division
The somatic sensory division
The autonomic nervous system
The somatic motor division
Erica has been standing in line to buy a cookie for over an hour. What muscle fiber type will predominantly be activated to allow Erica to stand for a long time?
What causes tropomysosin to move off of the actin active sites?
ATP binds to tropomyosin
Ca2+ binds to tropomyosin
ATP binds to troponin
Ca2+ binds to troponin
For a neuron action potential, what state are the voltage-gated Na+ and voltage-gated K+ channels in during the relative refractory period?
The Na+ channels are open and the K+ channels are in their resting state.
The K+ channels are open and the Na+ channels are in their resting state.
Both the Na+ and K+ channels are open.
Both the Na+ and K+ channels are closed.
What happens to "d" during a muscle contraction?
It gets larger
It remains unchanged
During excitation-contraction coupling, why is acetylcholine released into the synaptic cleft?
Na+ enters into the motor end plate through ligand-gated Na+ channels
Ca2+ enters into the axon terminal through voltage-gated Ca2+ channels
Acetylcholin-esterase diffuses into the axon terminal
K+ exits the axon terminal through voltage-gated K+ channels
True or False? An action potential and a muscle fiber twitch occur simultaneously.
What is the approximate resting membrane potential of a skeletal muscle fiber?