anat nervous vocab Flashcards
excitability
they can respond to changes in their surrounding. changes affect membrane potential by openeing gated ion channel
stimulus
changes affecting membrane potential (opening a gated ion channel) membrane potential becomes more negative
action potential
achieved after threshold potential is reached. neural impulse,
bigger diameter of axon, faster the impulse
extracellular fluid
bodily fluid outside cell
-70mV
resting potential, excess negative on inside
+30mV
peak of action potential, positive on the inside (depolarization)
-55mV
threshold potential, neuron depolarizing sufficiently n action potential result/nueral impulse
threshold
level of stimulation required to trigger an impulse
ion channels
membrane proteins whose functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ions across the cell membrane, controlling the flow of ions
Na+/K+ pump
actively transport sodium ions out of the cell and potassium ion into the cell,
potassium K: inside
sodium Na: outside
depolarizing phase
more positive than resting
all or none principle
muscle fiber/neuron completly responds when exposed to a stimulus of threshold strength
refractory period
time period following stimulation during which a neuron or muscle fiber will not respond to a stimulus, restablish its restin potential
repolarizing phase
the change in membrane potential that returns it to a negative value
resting membrane potential
difference in electrical charge between inside and pitsode(volt) when its nit sending impulse
ions follow diffusion, more permeable to postassium (move out more than sodium in)
outside: more positive
inside has anions
polarized
inside negative/ electrically charged
leakage channels
Ion channels which are always open; responsible for the resting membrane potential
anions
PO4-2
SO4-2
embrane potential
potential difference acros cell membrance (mV)
difference in electrical charge between inside and outside
leak
3 sodium leak into
2 potassium leak out. Na/K pump pump does the opposite to maintain balance
hypolarize
membrance potential becomes more negative than resting potential
action potential
in series
multipolar: first part of axon: trigger zone has voltage gated sodium, threshold: open n membrane potential: positive, vated closes quickly/ then potasium voltage open out then membrain repolarize n all gate closes
absolute refractory
membrane change in sodium permeability
relative refreactory
reestablishes its resting potential n stimulus w/ high intesity can trigger impulse
impulse in unmyelinated
over entire surface
myelin
insulator n prevent flow of ion through membrane. nodes of ranvier, channel open at here, n action potential only occure here: saltatory conduction, faster than unmyelinated
neurotransmitter
react w/ receptors in postsynaptic membrance (chemically gated) changes in these channels creat synaptic potential
synaptic potentials
depolarize/ hyerpolarize the recieving cell membrane
net effect determines whether action potential happen bc dendrites recieve messages from many axon
excitatiory postsynaptic potential
depolarizing membrance n could trigger action potential
sodium open
inhibitory postsynaptic potential
action potential not likely, hyperpolarizing
potessium open
chloride open
neurotransmitters
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