Exam 3- Muscular System

What actually does the shortening during contraction?

• actin

• myosin

• muscle fiber

• sarcomere

What happens to the filaments in accordance with the sliding filament theory?

• they shorten

• they move further away from each other

• they do not move

• they slide past each other

Which is correctly matched with its definition?

• membrane potential- In resting state all cells have voltage across membrane

  action potential- change or depolarization conducted along the membrane

• action potential- In resting state all cells have voltage across membrane

  membrane potential- change or depolarization conducted along the membrane

What steps must occur in order for a skeletal muscle to contract?

• nerve stimulation

• an action potential must be generated in sarcolemma

• action potential must be propagated along sarcolemma

• intracellular calcium levels must rise briefly

What are the parts of the neuromuscular junction?

• axon terminal

• junctional folds

• synaptic cleft

• myofilaments

What does the axon terminal have in it?

• fluid

• synaptic vesicles that contain ACh

• calcium, sodium, and potassium

• sarcolemma

What receptors are located in the junctional folds of the sarcolemma?

• ACh receptors

• Na+ receptors

• K+ receptors

• Ca2+ receptors

When the nerve impulse arrives at the axon terminal, what happens?

• the muscle contracts

• the action potential travels down the sarcolemma

• ACh is released into the synaptic cleft

• myofilaments slide past each other

What is end plate potential?

• Generation and propagation of an action potential (AP)

• reaching threshold

• Restoration of resting conditions (resting membrane potential)

• Localized depolarization at the NMJ caused by ACh release opening ligands

What does the generation and propagation of an action potential cause?

• repolarization

• depolarization

• hyperpolarization