Exam 5 Chapter 12: Part 2

Front 1

action potentials arise according to the:

Back 1

all or none principle

Front 2

how does an action potential that is always the same size occur?

Back 2

when depolarization reaches the threshold, the voltage gated channels open and

Front 3

different neurons have many different thresholds for generation of an action potential, but the threshold in any one neuron is

Back 3

usually constant

Front 4

the period of time after an action potential begins and the cell cannot generate another action potential is called

Back 4

refractory period

Front 5

no action potential generated during what period

Back 5

absolute refractory period:

Front 6

time during which a second action potential can be initiated, but only with larger than normal stimulus

Back 6

relative refractory period

Front 7

the generation of the action potential depends on:

Back 7

a particular stimulus that is able to bring the membrane potential to a threshold

Front 8

what is a stimulus that hasa weak depolarization that cannot bring the membrane potential to threshold?

Back 8

subthreshold stimuli

Front 9

an action potential occures in the membrane of the axon of a neuron when depolarization reaches a certain level termed the

Back 9

threshold

Front 10

step by step depolarization and repolarization of each adjacent segement of the plasma membrane is called the

Back 10

continuous conduction

Front 11

in ___, the ions flow through their voltage-gated channels in each adjacent segment of the membrane

Back 11

continuous conduction

Front 12

the special mode of action potential propagation that occures along myelinated axons, occurs because of the uneven distribution of voltage-gated channels

Back 12

saltatory conduction

Front 13

a synapse is essential for homeostatis because they

Back 13

allow information to be filtered and intergrated

Front 14

at a synapse between nuerons, the neuron sending the signal is called the :
and the neuron receiving the message is called the :

Back 14

presynaptic neuron


postsynaptic neuron

Front 15

what conducts impulses via gap junctions

Back 15

electrical synapses

Front 16

electrical synapses have two main advantages:

Back 16

faster communication

synchronization ( a large number of neurons can produce action potentials in unison)

Front 17

chemical synapses produce

Back 17

postsynaptic potentials

Front 18

what is a graded potential created by postsynaptic neurons from a chemical signal

Back 18

postsynaptic potentials

Front 19

chemical synapses also have a synaptic delay which is the:

Back 19

the time it takes for these processes to occur

Front 20

depolarizes the postsynaptic membrane (brings it closer to threshold)

Back 20

excitatory postynaptic potential

Front 21

Excitatory postsynatpic potentials result from opening of

Back 21

cation channels

Front 22

a hyperpolarizing postsynaptic potential is termed an

Back 22

inhibitory postsynatpic potential.

Front 23

inhibitory postsynatpic potentials result from the opening of

Back 23

ligand channels

Front 24

brings the postsynaptic membrane away from threshold

Back 24

inhibitory postsynatpic potential.

Front 25

removal of neurotransmitter:

3 steps

Back 25

1. diffusion
2. enzymatic degradation
3. uptake by cells
reuptake and uptake

Front 26

release of the neurotransmitter from the synaptic cleft is essential for:

Back 26

normal synaptic function