PNB 2264 QUIZ 6 2026 QUESTIONS AND ANSWERS | A+ GRADED | WITH EXPERT
SOLUTIONS
What bands shorten during contraction? - (answer)I band and H band as the Z line pulls toward the M
line
neuromuscular junction - (answer)point of contact between a motor neuron and a skeletal muscle cell
where are motor neurons activated? - (answer)spinal cord gray matter (ventral)
threshold - (answer)the minimal amount of stimulus required for motor neuron activation
all-or-none response - (answer)a neuron's reaction of either firing (with a full-strength response) or not
firing.
recruitment - (answer)when several motor units are activated and the muscle contraction grows in
strength
myelin sheet of motor neuron - (answer)propagate action potentials fast and at long distances
Acetylcholine - (answer)A neurotransmitter that triggers muscle contraction
motor end plate - (answer)the flattened end of a motor neuron that transmits neural impulses to a
muscle
Voltage-gated Ca2+ channels - (answer)An action potential releases neurotransmitter from a neuron and
opens these channels by depolarizing the plasma membrane and they allow Ca2+ to diffuse into the
terminal
How does Ca2+ cause muscle contraction? - (answer)binds to proteins that allow Ach neurotransmitter
containing vesicles to fuse with presynaptic terminal and be released into the synaptic cleft
SOLUTIONS
What bands shorten during contraction? - (answer)I band and H band as the Z line pulls toward the M
line
neuromuscular junction - (answer)point of contact between a motor neuron and a skeletal muscle cell
where are motor neurons activated? - (answer)spinal cord gray matter (ventral)
threshold - (answer)the minimal amount of stimulus required for motor neuron activation
all-or-none response - (answer)a neuron's reaction of either firing (with a full-strength response) or not
firing.
recruitment - (answer)when several motor units are activated and the muscle contraction grows in
strength
myelin sheet of motor neuron - (answer)propagate action potentials fast and at long distances
Acetylcholine - (answer)A neurotransmitter that triggers muscle contraction
motor end plate - (answer)the flattened end of a motor neuron that transmits neural impulses to a
muscle
Voltage-gated Ca2+ channels - (answer)An action potential releases neurotransmitter from a neuron and
opens these channels by depolarizing the plasma membrane and they allow Ca2+ to diffuse into the
terminal
How does Ca2+ cause muscle contraction? - (answer)binds to proteins that allow Ach neurotransmitter
containing vesicles to fuse with presynaptic terminal and be released into the synaptic cleft
