Graded Potentials OS 12.5.1 cfu quiz

Which of the following best describes graded potentials in neurons?

• Local changes in membrane potential associated with synapses

• Permanent changes in membrane potential at the axon hillock

• Only hyperpolarizing changes in the membrane potential

• Changes that only occur in muscle cells

What ions are primarily responsible for depolarizing graded potentials?

• Na+ and Ca2+

• K+ and Cl-

• Mg2+ and Fe2+

• H+ and OH-

Which of the following would most likely cause a hyperpolarizing graded potential? (choose all that apply)

• K+ leaving the cell

• Na+ entering the cell

• Ca2+ entering the cell

• Cl- entering the cell

A larger stimulus applied to a neuron will result in which of the following, according to the concept of graded potentials?

• A greater change in membrane potential

• No change in membrane potential

• A smaller change in membrane potential

• The same change as a smaller stimulus

A stimulus that depolarizes the membrane above the threshold may trigger which of the following?

• An action potential in a postsynaptic neuron

• Hyperpolarization of the membrane

• Inhibition of all ion channels

• Complete loss of membrane potential

What is the graded potential in the dendrites (and soma) of a neuron that is receiving neural transmissions from other cells called?

• Generator potential

• Receptor potential

• Postsynaptic potential (PSP)

• Action potential

Which type of postsynaptic potential causes the membrane potential to move toward threshold?

• Inhibitory postsynaptic potential (IPSP)

• Excitatory postsynaptic potential (EPSP)

• Generator potential

• Receptor potential

Explain the difference between spatial and temporal summation in neurons.

• Spatial summation involves one input at one location; temporal summation involves multiple inputs at different locations.

• Spatial summation is the result of multiple graded potentials at different locations; temporal summation is the result of multiple action potentials from a single cell over time.

• Spatial summation is unrelated to membrane potential; temporal summation is related to neurotransmitter release.

• Spatial summation only occurs in sensory neurons; temporal summation only occurs in motor neurons.

Why do the initial segment and axon hillock have a high density of voltage-gated Na+ channels?

• To maintain the resting membrane potential

• To initiate the depolarizing phase of the action potential

• To inhibit neurotransmitter release

• To prevent summation of graded potentials

Explain how the summation of excitatory and inhibitory postsynaptic potentials at the axon hillock can influence whether a neuron will fire an action potential.

• The combined effect of EPSPs and IPSPs determines if the threshold for firing an action potential is reached.

• Only EPSPs are important for firing an action potential.

• IPSPs always prevent action potentials from occurring.

• The axon hillock does not play a role in action potential initiation.