Identify which channels are located in the dendrites and cell body (soma) of neurons. Identify all that apply. a. Ligand-gated ion channels b. Leak channels c. Mechanically gated channels d. Voltage-gated ion channels 2. At which specific location of the neuron will an action potential be initiated? a. Dendrites b. Cell body c. Axon d. Initial segment/trigger zone e. Axon hillock 3. At which location of the neuron will a graded potential be initiated? a. Dendrites b. Cell body c. Initial segment/trigger zone d. A andb e. B and c The Nodes of Ranvier that are unmyelinated sections of the axon are important for propagating an action potential because of 4. Greater numbers of ligand-gated Na” channels Greater numbers of voltage-gated Na* channels a. b. 5. A graded potential is , whereas an action potential is a. Irreversible, reversible b. Reversible, irreversible c. Reversible, reversible d. Irreversible, irreversible 6. During the refractory period a neuron cannot initiate another action potential because a. Cl channels are open. b. Na* channels are inactive c. K+ channels are open. d. Cl channels are closed e. All of the above summation is when more than presynaptic neuron stimulates a postsynaptic neuron at different location at the same time. a. Spatial b. Temporal summation is the response of a postsynaptic neuron to a presynaptic neuron stimulating at the same location, but at different times. a. Spatial b. Temporal Matching (0.5 pts each) Amplitude depends on strength of stimulus A. Action potential Depolarizing or hyperpolarizing All or none amplitude Depends on ligand-gated ion channels Origin is at trigger zones Always depolarizing, repolarizing, return to resting B. Graded potential membrane potential No refractory period Depends on voltage-gated Na+ and K+ channels Summation can occur Travels short distance