CH.9 Module 3: Section 9.04
Identify the step in the phases leading to muscle fiber contraction indicated by "A."
ACh released; binds to receptors on sarcolemma.
Identify the step in excitation-contraction coupling in skeletal muscle indicated by "A."
Action potential is propagated along the sarcolemma and down the T tubules.
Match the following area with the correct term: Contains vesicles filled with acetylcholine.
Axon terminal
Match the following protein with its action: Troponin.
Binds Ca2+ and starts the contraction cycle
What is the cause of rigor mortis?
Calcium influx and lack of ATP
Identify the step of the cross bridge cycle in skeletal muscle indicated by "D."
Cocking of the myosin head
Identify the step of the cross bridge cycle in skeletal muscle indicated by "C."
Cross bridge detachment
Match the following term with the correct description: End plate potential.
Depolarization occurring only at the neuromuscular junction
Match the following chemical with its function: Acetylcholinesterase.
Enzyme released into neuromuscular junction to break down acetylcholine
Identify the step in the phases leading to muscle fiber contraction indicated by "D."
Excitation-contraction coupling occurs
Match the description to the event in the generation and propagation of an action potential: Propagation of the action potential.
Increased positive charge inside sarcolemma changes permeability of adjacent areas, opening voltage-regulated Na+ channels
Identify the step in the phases leading to muscle fiber contraction indicated by "C."
Local depolarization (end plate potential) ignites AP in sarcolemma
Select the correct description of ion movement at the neuromuscular junction that produces the end plate potential.
More sodium enters the muscle fiber than potassium leaves the muscle fiber.
Which of the following is an autoimmune disease that destroys acetylcholine receptors?
Myasthenia gravis
Match the following term with the correct description: Action potential.
Propagation of an electrical current along the sarcolemma
Match the following chemical with its function: Ca2+.
Released by terminal cisternae into the sarcoplasm to bind with troponin
Match the following term with the correct description: Repolarization.
Restoration of the membrane potential to resting potential
Match the description to the event in the generation and propagation of an action potential: Repolarization.
Restoring the sarcolemma to its initial polarized state (negative inside, positive outside)
Identify the step in the phases leading to muscle fiber contraction indicated by "E."
SR releases Ca2+; Ca2+ binds to troponin; myosin-binding sites (active sites) on actin exposed
Select the correct description of the voltage-gated ion channels for a region of sarcolemma that is undergoing depolarization.
Sodium channels are open and potassium channels are closed
Select the correct description of the voltage-gated ion channels for a region of sarcolemma that is undergoing repolarization.
Sodium channels close and potassium channels open
Match the following term with the correct description: Refractory period.
The time when a fiber cannot be stimulated until repolarization is complete
Acetylcholinesterase __________.
breaks down acetylcholine
Identify the step of the cross bridge cycle in skeletal muscle indicated by "A."
cross bridge formation
Identify the step in the phases leading to muscle fiber contraction indicated by "B."
motor nueron stimulates muscle fiber
The refractory period in which the muscle will not contract if stimulated occurs during __________ of the muscle cell.
repolarization
The space between the axon terminal of the motor neuron and the muscle fiber is called the __________.
synaptic cleft
When an action potential arrives at the neuromuscular junction, the most immediate result is __________.
the release of acetylcholine from the motor neuron
