Muscle Contraction Quiz

What must stimulate skeletal muscles in order for them to contract?

• Sensory neuron

• Motor neuron

• Muscle fiber

• Blood vessel

What is a motor unit?

• A group of motor neurons

• A single muscle cell and its nerve supply

• One motor neuron and all the skeletal muscle cells stimulated by that neuron

• A bundle of muscle fibers

What is the structure labeled as "Motor unit 1" in Figure 6.4a?

• A group of muscle fibers innervated by the axon terminals of a single motor neuron

• A single muscle fiber connected to multiple motor neurons

• The part of the spinal cord that sends signals to muscles

• The axon terminals at the neuromuscular junctions

Where are the axon terminals of motor neurons located as shown in Figure 6.4a?

• At the end of the muscle fibers

• Within the spinal cord

• At the beginning of the nerve

• At the neuromuscular junctions

What are the axon terminals at neuromuscular junctions connected to?

• Bone cells

• Muscle fibers

• Blood vessels

• Nerve cells

What is the role of the branching axon in the motor unit?

• To transmit signals to the muscle fibers

• To provide nutrients to the muscle fibers

• To remove waste from the muscle fibers

• To insulate the muscle fibers

What is the role of acetylcholine (ACh) at the neuromuscular junction?

• It is the site of association between the axon terminal and sarcolemma.

• It is a chemical released by the nerve upon arrival of nerve impulse in the axon terminal.

• It is the neurotransmitter that stimulates skeletal muscle.

• It is the association site of axon terminal of the motor neuron and sarcolemma of a muscle.

What is the neuromuscular junction?

• A chemical released by nerve upon arrival of nerve impulse in the axon terminal.

• The neurotransmitter that stimulates skeletal muscle.

• The association site of axon terminal of the motor neuron and sarcolemma of a muscle.

• A type of nerve cell that transmits signals.

What is the synaptic cleft?

• The direct contact point between a nerve and a muscle

• The gap between nerve and muscle filled with interstitial fluid

• A type of neuron

• A muscle protein

Do the nerve and muscle make contact at the synaptic cleft?

• Yes, they are fused together

• Yes, but only under certain conditions

• No, although they are very close

• No, they are separated by a large distance