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Electrical transmission uses ___ _______ across the membrane to generate electrical potentials
ion channels
In chemical transmission, 2 neurons are not directly connected.. one neuron releases ________ _________ at the terminal which act on the next neuron through receptors to initiate an electrical signal
chemical messengers
ion channels are usually _______, meaning when they are open, ion movement is along the concentration gradient.
ion channels can be _____ ______, meaning they open when the membrane reaches a given potential
voltage gated
Na+/K+ ATPase pump use ___ to move ions _____ their concentration gradients
ATP, against
ion channels that open when ligand bind to the receptor on the surface:
ligand gated
Intracellular Na+ and Cl- is ______, while extracellular K+ is _____.
high, low
A means of calculating the equilibrium potential of a given ion across the membrane
nernst equation
resting membrane potential:
-70 mv
Resting membrane potential is primarily driven by the flux of __ out of the cell down its concentration gradient through ____ __ channels
K+, leak K+
The Na+/K+ ATPase pump maintains the negative membrane potential by actively pumping __ out of he cell and __ into the cell against their concentration gradients
Na+, K+
Moving the membrane potential from negative toward zero
The polarization of the membrane from zero to a positive
Going back to the negative resting membrane potential
Going more negative than the resting membrane potential
First step of action potential (rise)
Na+ channels open, Na+ enters cell
Second step of action potential (top of peak)
K+ channels open, K+ begins to leave cell, Na+ channels close
Third step of action potential (fall)
K+ channels close
Last step of action potential (leveling out)
Excess K+ outside diffuses away
Sodium channels open and inactivate very _____
Potassium channels open and close _____
A period of time during which a second stimulus cannot induce a new action potential
absolute refractory period (Na+ channels cannot re-open)
A period of time after the absolute potential can be induced but requires a stronger stimuli
relative refractory period (some, but not all Na+ channels have returned to their resting state)
Saltatory conduction - action potentials only occur at ______ __ _______
nodes of Ranvier
Saltatory conduction - implies jumping of AP, but it doesn't actually jump it _______ __ ____ ____
regenerates at each node
Saltatory conduction means ________ __________ is much faster than an unmyelinated axon.
signal propagation
Synaptic transmission involves... (3)
neurotransmitter molecules, synapse, receptor
This type of signal allows information from many different sources to influence a cell's activity
This type of signal allows one cell to influence multiple pathways
The ________ terminal contains synaptic vesicles, which hold the neurotransmitter.
The ________ ______ is a 10-20nm space between the cells
synaptic cleft
The __________ _______ is populated with receptors, which allow the initiation of the new action potential in the receiving cell
postsynaptic density
Synaptic transmission - _____ ______ triggers release of neurotransmitters
action potential
Activation of the postsynaptic cell involves _ proteins
G (metabotropic)
The binding of a ligand (the neurotransmitter) to the receptor opens the ion channel
The binding of a ligand to the receptor activates a SECOND MESSENGER protein, a G protein, which can either directly activate an ion channel or activate an intracellular signaling cascade which will activate an ion channel
(ionotropic vs. metabotropic) Bottom line: most of the time, _____ ______ opens ion channels
receptor activation
Negative interior of cell, means that it is ____polarized
Positive interior of cell, means that it is ____polarized
EXCITATORY SYNAPSES usually involve the opening of __ or __ channels
Na+ or Ca2+
INHIBITORY SYNAPSES usually involve the opening of __ or _ channels
Cl- or K+
A change in membrane potential relative to resting potential is known as a _______ _________
graded potential
The potential changes in the membrane that occur at an excitatory synapse (depolarize - Na+ channels)
excitatory postsynaptic potentials (EPSP)
The potential changes that occur at an inhibitory synapse (hyperpolarize - Cl- channels)
inhibitory postsynaptic potentials (IPSP)
Synaptic integration - temporal means
Synaptic integration - spatial means
2 different synapses fired
Ach is inhibitory or excitatory?
Glutamate is inhibitory or excitatory?
GABA is inhibitory or excitatory?

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