Anatomy - NMJ and Muscle Contraction

The gap between the nerve cell and sarcolemma is the ____ ___.

• Synaptic cleft

• Neurotransmitter

• Motor unit

• Neuromuscular junction

What is the specific neurotransmitter that stimulates the movement of skeletal muscles?

• GABA

• Acetylcholine

• Serotonin

• Dopamine

Once the action potential reaches the end of the pre-synaptic terminal what takes place?

• ACh is released into the synaptic cleft.

• Calcium is pumped into the sarcolemma.

• Calcium is pumped into the presynaptic terminal.

• The muscle contracts.

Once calcium is pumped into the presynaptic terminal what happens?

• The muscle contracts

• ACh is released into the synaptic cleft.

• Sodium pumps into the sarcolemma.

• The muscle contracts.

What is the name of the component that houses the neurotransmitters?

• Synaptic cleft

• Acetylcholine

• Receptors

• Synaptic vesicles

What causes the sodium channels on the muscle to open?

• Acetylcholine binds to the Na+ channel

• Acetylcholine binds to the synaptic vesicles

• the Ca2+ channels open

• The action potential is generated in the muscle cell

An action potential is

• A positive charge that moves along the neurons

• A negative charge that moves along the neurons

• The neutral charge of cells at rest

Once ACh binds to receptor cells on the sarcolemma, what takes place?

• Sarcolemma becomes temporarily permeable to sodium.

• The muscle contracts.

• Calcium is pumped into the axon terminal.

• Synaptic vesicles move to the end of the terminal.

A crossbridge is

• when the myosin head binds to actin

• when calcium ions attach to troponin

• when the ACh attaches to the sarcolemma

• when the T-tubles stimulate the sarcoplasmic reticulum

ACh that diffuses across the synaptic cleft attach to

• receptors on the sarcolemma

• troponin on the actin molecule

• the sarcomere to stimulate contraction

• myosin heads to form crossbridges