A&P CH11 PT3
What membrane potential must generally be met in order to achieve threshold?
-55 mV
Salatory conduction occurs when
Myelin sheath is present
The presence of a synaptic cleft between cells is characteristic of __________.
chemical synapse
Voltage-gated sodium channels have both an activation gate and a(n) ________ gate.
inactivation gate
Which statement best describes the all or none principle
An action potential happens completely, or it doesn't happen at all.
The majority of synapses in the nervous system are
Chemical
During repolarization of a neuron
Returns to a negative state/resting membrane potential
Repolarization begins as
Sodium channels close and potassium opens
What happens when Voltage gated sodium channels are activated
Sodium ions enter and depolarization happens
During the absolute refractory period
no stimulus of any strength will trigger a new action potential
A neuron that receives neurotransmitter from another neuron is called
postsynaptic neuron
Action potential order
Top to bottom 4,2,5,1,3 1.)Local potential depolarizes the axolemma of a trigger zone to threshold 2.) voltage gated sodium ions enter and axon section depolarizes 3.) sodium channels inactivate and voltage gated potassium ions active are. Sodium stops entering and potassium leave, beg reploarization 4.) sodium returns to resting state and repolarization continues 5.) as postassium ion channels return to resting state, axolemma May hyperpolarize b4 re but to resting membrane pot
Which type of fiber has the largest diameter?
Type A
Determine the fiber type in which propagation of an action potential will occur most quickly.
Type A myelinated
When is the generation of an action potential impossible, no matter the strength of the stimulus?
absolute refractory period
What is more likely to promote an action potential?
depolarization