Chapter 12 Vocab 3

Question 1

excitable membrane

Answer 1

cell membrane that regulates the movement of ions so that an action potential can be generated

Question 2

resting potential

Answer 2

the difference in voltage measured across a cell membrane under steady-state conditions, typically -70 mV

Question 3

sodium-potassium pump

Answer 3

• aka Na/K ATPase)
• membrane-embedded protein pump that uses ATP to move sodium out of a cell and potassium into the cell
• powdered by ATP
• maintains resting potential and balances passive forces of diffusion
• 3 Na out and 2 K in

Question 4

threshold

Answer 4

membrane voltage at which an action potential is initiated

Question 5

action potential

Answer 5

change in voltage of a cell membrane in response to a stimulus that results in transmission of an electrical signal; unique to neurons and muscle fibers

Question 6

depolarization

Answer 6

change in a cell membrane potential from rest toward zero

Question 7

repolarization

Answer 7

return of the membrane potential to its normally negative voltage at the end of the action potential

Question 8

hyperpolarization

Answer 8

• when the membrane potential becomes more negative at a particular spot on the neuron’s membrane
• an increase in negative charge on the inside of the neuron

Question 9

absolute refractory period

Answer 9

time during an action period when another action potential cannot be generated because of the voltage-gated Na channel is inactivated

Question 10

relative refractory period

Answer 10

• time after the initiation of an action potential when another action potential cannot be generated
• a time in which the neuron can fire an action potential, but it needs a greater stimulus

Question 11

nerve impulse

Answer 11

• signals carried along nerve fibers
• basically an action potential

Question 12

propagation

Answer 12

movement of an action potential along the length of an axon

Question 13

excitatory neurotransmitters

Answer 13

• promotes the generation of an action potential in the receiving neuron
• function to activate receptors on the postsynaptic membrane and enhance the effects of the action potential

Question 14

inhibitory neurotransmitters

Answer 14

• prevents the generation of an action potential in the receiving neuron
• function to prevent an action potential