Action Potential

Match the stages of an action potential to the correct characteristics. Depolarization Membrane becomes less negative -70 mV --> +30 mV Sodium channels open; Potassium channels closed Repolarization Membrane returns to resting membrane potential +30 mV --> -70 mV Sodium channels closed; Potassium channels open Hyperpolarization Membrane becomes even more negative -70 mV --> -90 mV Sodium channels remain closed; Potassium channels remain open longer Resting Membrane Potential -70 mV Sodium channels closed; Potassium channels closed Match the Action Potential Vocabulary to the correct definition. Action Potential Electrical impulse that travels down the axon Graded Potential Electrical impulse that travels down the dendrites Resting Membrane Potential The charge difference across a membrane when it is polarized; -70 mV Threshold The level of depolarization to guarantee an action potential is created Match the correct characteristics to either an Action Potential or Graded Potential. Action Potential Occurs in axons Occurs in neurons and muscles Travels over a long distance Created by graded potentials Do not decrease in strength over a distance One Size Fits All Travels away from cell body Graded Potential Occurs in dendrites Occurs only in neurons Travels over a short distance Creates action potentials Decrease in strength over a distance Magnitude varies with strength of stimulus Travels toward cell body Match the Action Potential Vocabulary to the correct definition. Chemically gated channel Channel that opens in response to neurotransmitter Mechanically gated channel Channel that opens in response to touch Voltage gated channel Channel that opens in response to changes in membrane potential Leakage channels Channels that are always open therefore do not respond to any stimuli Imagine that you are starting at the dendrite and the chemically gated sodium channels have just opened allowing sodium to rush into the dendrite. Place the following steps in the proper order starting after that. 1 Depolarization of the dendrite leads to the formation of a graded potential 2 Graded potentials travel towards and collect at the axon hillock 3 Voltage-gated sodium channels open at the axon hillock and the axon hillock depolarizes 4 An action potential forms at the axon hillock and travels down the length of the axon 5 The action potential reaches the axon terminals 6 Calcium channels open and calcium flows into the axon terminals 7 The presence of calcium causes synaptic vesicles to release neurotransmitters into the synaptic cleft 8 The neurotransmitter diffuses across the cleft and binds to receptors on the dendrites of the postsynaptic neuron 9 Chemically-gated sodium channels on the dendrites of the postsynaptic neuron open and sodium flows in