8.3 Neuron Communication

Which of the following best describes what happens when a stimulus is under the threshold in a neuron?

• It causes a small depolarization or hyperpolarization

• It always triggers an action potential

• It causes the neuron to divide

• It has no effect on the neuron

Where do graded potentials usually occur in a neuron?

• Axon terminal

• Dendrite or cell body

• Myelin sheath

• Synaptic cleft

What determines the strength of a graded potential?

• The number of synapses

• The strength of the stimulus

• The length of the axon

• The amount of neurotransmitter released

A student observes that a graded potential is stronger when the stimulus is stronger. Which concept does this observation best illustrate?

• Graded potentials are all-or-none

• Graded potentials depend on the strength of the stimulus

• Graded potentials only occur in axons

• Graded potentials do not change with stimulus strength

Which of the following best describes a presynaptic neuron?

• The neuron that transmits electrical impulses away from the synapse

• The neuron that conducts electrical impulses towards the synapse

• The neuron that only receives chemical signals

• The neuron that is always postsynaptic

What is a key characteristic of electrical synapses?

• They are more common than chemical synapses

• They transmit signals through neurotransmitters

• They transmit signals directly to other neurons through gap junctions

• They are slower than chemical synapses

Which type of synapse is more common in the nervous system?

• Electrical synapse

• Axodendritic synapse

• Chemical synapse

• Axosomatic synapse

What is released at chemical synapses to transmit information between neurons?

• Neurotransmitters

• Hormones

• Enzymes

• Ions

At a chemical synapse, what triggers the release of neurotransmitters from the axon terminal?

• Arrival of an action potential

• Increase in temperature

• Decrease in pH

• Presence of light

What is the function of synaptic vesicles in the axon terminal?

• They store neurotransmitters

• They generate action potentials

• They absorb excess neurotransmitters

• They produce myelin