PGY 412: Exam 1
50 Cards in this Set
Front | Back |
---|---|
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.
|
passive
|
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
|
depolarization
|
The polarization of the membrane from zero to a positive
|
overshoot
|
Going back to the negative resting membrane potential
|
repolarization
|
Going more negative than the resting membrane potential
|
hyperpolarization
|
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 _____
|
rapidly
|
Potassium channels open and close _____
|
slowly
|
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
|
convergence
|
This type of signal allows one cell to influence multiple pathways
|
divergence
|
The ________ terminal contains synaptic vesicles, which hold the neurotransmitter.
|
presynaptic
|
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
|
ionotropic
|
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
|
metabotropic
|
(ionotropic vs. metabotropic) Bottom line: most of the time, _____ ______ opens ion channels
|
receptor activation
|
Negative interior of cell, means that it is ____polarized
|
hyper
|
Positive interior of cell, means that it is ____polarized
|
de
|
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
|
time
|
Synaptic integration - spatial means
|
2 different synapses fired
|
Neurotransmitters are all VERY DIVERSE, YET ALL CLASSIFIED AS NEUROTRANSMITTERS. Ok?
|
Ok
|
Ach is inhibitory or excitatory?
|
excitatory
|
Glutamate is inhibitory or excitatory?
|
excitatory
|
GABA is inhibitory or excitatory?
|
inhibitory
|