PSC 101 Midterm 2

Axon

part of neuron that transmits a signal away from neurons cells body and carries signal to another location

Neurotransmitter

chemical released by neurons to stimulate adjacent neuron

Synapse

area including presynaptic membrane of one neuron and postsynaptic membrane of another neuron, and tiny gap between

Presynaptic membrane

cell membrane of neuron sending information across synapse

Postsynaptic membrane

cell membrane of neuron receiving information across synapse

Threshold

activity level at which cell/detector responds or fires

Action potential

brief change in electrical potential of axon, Physical basis of signal sent from one end of a neuron to the use, threshold where the voltage gated sodium channels open —> causing more sodium to come in

Myelin sheath

layer of tissue formed by specialized glial cell that provide insulation around axons of many neurons, Gaps in insulation and neuronal signal essential jumps from one gap to the next —> it speeds up the transmission of actions potentials

All or none law

neuron or detector either fires completely or does not fire at all, no intermediate responses are possible

what does sodium potassium pump?

use energy to move sodium out and potassium to the neuron —> pushing the ball up the hil

depolarization

caused by stimulation of the neuron, causes sodium to enter neuron

refractory period

neuron is inhibited(its ability to fire an electrical impulse (action potential) is reduced, blocked, or suppressed by another neuron

nodes of ranvier

small gaps in the insulting myelin sheath

saltatory conduction

axon potential travels inside the axon and jumps from node to node

hyper-polarization

caused by inhibitory messages that decrease the probablity the neuron will fire an action potential, which causes Inhibitory postsynaptic potential from chloride ions (CI-)

caused by excitatory messages, and increases the probability that the neuron will fire an action potential and results in excitatory postsynaptic potential from sodium ions (NA+)

spatial summation

the summing of potentials that come from different parts of the cell

temporal summation

the summing of potentials that arrive at the axon hillock at different times