Ch. 4 Flashcards
opposite charges ___, like charges ___
attract, repel
overall the bodies charge is
neutral
calcium, chloride and sodium are higher concentration inside or outside?
outside
the bigger the difference between concentration inside and outside makes a larger _____
gradient
both sodium and potassium have pumps and ___ channels
leak (allow them to freely move)
potassium had permability of
1 (most permeable)
sodium has permability of
0.04
chloride has permability of
0.45
what is resting membrane potential
-70mV
when the cell is at rest voltage gated channels can act as ___ channels
leak
NT are made in the __ __ (nucleus, ER, golgi)
cell body
there are two types of axonal transport
slow and fast
the fast axonal transport uses _____ to deliver NT
anterograde
using fast axonal stransport vesicles are recycled via
retrograde transport
graded potential are triggered by information input from ____ neuron
outside
graded potentials happen where
dendrites and cell body
graded potential ions
Na+, K+ and Ca+ (usually sodium)
there are three possible effects on membrane potential from a graded potential
depolarizing, hyperpolarizing, repolarizing
for a _____ potential there is no minimum strength required to intiate
graded
with a graded potential the goal is to get to ____
threshold (-55mV)
two stimuli in close succession of time
temporal summation
stimuli are separated in space but at same time
spatial summation
EPSP of 30 and IPSP of 40, what is resting membrane potential
-80mV
in ___ potentials it is local and only spreads within the neuron (not propogated) gets weaker over time
graded
types of channels in action potential
voltage gated
an ____ potential is only depolarizing
action
action potentials only move in ___ direction
one; new action potential initiated in each segment of axon
action potential: when the membrane is depolarizing what is moving into cell (30mV)
Na+ (EPSP)
the voltage gated Na channels can have what confirmations
closed open inactive
Sodium is following its chemical and electrical gradient when it ____ the cell
depolarizes
the voltage gated K+ channels have two confirmations
open and closed
in repolarization the sodium channel is, at resting it is
inactive, closed
potassium doesnt open until _____ (slow) and stay open until hyperpolarization
overshoot
until you reach threshold the graded potential channels are typically ____ gated
ligand
the refractory periods have two functions
limit # of action potentials, one-way propagation
An absolute refractory period means
there cannot be another action potential no matter what
what does a relative refractory period mean
a larger than normal stimulus is needed to start action potential
the larger the diameter of an axon the ___ the action potential
faster
you only have voltage gated ion channels at the ___ ___ __
nodes of ranvier
electrical synapse are a ____ transfer of charge because of __ ___
direct, gap junction
electrical synapse has unirdirectional or bidirectional synapse
bidirectional
chemical synapse is an ___ transfer of action potential using what and are unidirectional
indirect, neurotransmitter
a ___ has a direct effect on signal transmission and can be excitatory or inhibitory
NT
receptor that is ligand gated, fast and ion specific
ionotropic
receptor that is slow and g-protein coupled
metabotropic
the active zone of an axon terminal has what (preynaptic cell)
synaptic neurotransmitter vesicles and voltage gated Ca+ channels
the more ___ you let in the more NT you let out at presynaptic cell
calcium
the postsynaptic cell has
NT receptors and breakdown enzymes
the NT can be removed how
uptake, diffusion away from cleft, chemically inactivated
monoamine oxidase is an enzyme that breaks down what
monoamine
what are modifications that can be done at the synapse
amount of Ca in cell, neurotransmitter production, global or general inhibition: IPSP, and selective inhibition
global inhibition means
shut down whole neuron
selective inhibition
there is axoaxonic synapse that is blocking one of the targets
what toxin blocks NT release (inhibits SNARE) to inhibitory neurons, causes severe muscle contractions
clostridium tetani
blocks NT release to excitatory neurons, reduces muscle contractions
clostridium botulinum
disease binds to ACh receptors but doesn’t open ion channels, decrease muscle action
curare
inactive Ache; continued presence of Ach and loss of sensitivity
nerve gas
