Transmission 2 Resting Membrane Potentials Flashcards
Why do we call it a membrane potential?
because inside of cell has a different change then outside the cell
what is the usual internal cell voltage at rest?
-70MV
Membrane permeability is _______ for NA+ ad K+ ions.
diffrent
there are ______ ___leak channels than ___ leak Channels
more K+, Na+
K+ ions ______ _____ as Na+ ____ ___ .
leak out, leak in
what maintains resting membrane potential?
Na+ -K+ Pump
An alteration in the potential surrounding a membrane causes a neuron to produce a ______ ______ or triggers _____ ______ to contract
nerve impulse
muscle fibers
what 2 things are referred to as excitable cells
neurons and muscle fibers
when an excitable cell is inactive it is at its?
resting potential
changes in membrane potential result in either a _____ _____ or an _____ ______
graded potential
action potential
what is a graded potential?
impulses that excite or inhibit further action
what is an action potential?
in a nerve fiber it stimulates a ____ _____ and in a muscle fiber it stimulates _______
some kind of response
nerve impluse
contraction
what are ion channels?
tube-shaped protien channels across the memebrane
what do ion channels do?
allow specific ions to move across the membrane
the direction of ion flow through a channel depends on the _______ in concentration of ____ _____ action on the ion.
difference
electrical charge action
ions passively defuse through a Chanel from ______ to _____ concentration. they are also attracted by _____ _____. or repelled by ______ charges
high to low
opposite charges
like
the direction of ion flow depends on _____ and _____ forces acting on the ion at any given time.
chemical and electrical
there are ___ types of channels of which ions can pass
4
keak channels contribute greatly to matinice of ____ ____ potential
resting membrane
a chemically gated channel has a _____ associated with it.. wha
receptor
when a chemically gated channel is occupied by a neaurotransmitter the gate of the channel _____ allowing a _____ type of ion to diffuse through. the gate will remain open as long as the ____ is ____
opens.
specific
receptor is occupied
a voltage-gated channel opens at a specific voltage known as the ______.
threshhold
the threshold for a voltage-gated sodium channel is around.
-55mv
when the membrane increases from its resting potential of ___ to the _____ the Chanel gate opens and sodium diffuses through the channel to the other side of the membrane.
-70mv
threshold
channels open at varying speeds despite reaching ____ at the same time
threshold
some voltage-gated channels have an additional gate known as?
inactivation gate
inactivation gates ______ _____ the channel so ions _____ pass trough even if their activation gate is open
temporarily plug
cannot
inactivation gate propose is so that ions ___ ____ pass through the gate at an _____ time
do not
appropriate
mechanically gated chenels are found in?
found primarily in the ______ to inform the NS of _____ changes in the surface of the body resulting from conditions in the envirmoment
sensory receptors
skin
mechanical
mechanically gated channels open when _______, _______ or _____ is applied to the membrane
pressure, touch or stretch
an ion pump is a type of membrane _____ protein
transport
an ion pump requires ____ to push ions form areas of ______ concentration to areas of _____concentration.
energy
lower, higher
what pump is most important in maintenance of membrane potnetial?
Sodium potassium pump
the Sodium potassium pump uses what as energy?
ATP
Sodium potassium pump pumps _____ sodium ions out of the cell and ___ potassium ions into the cell AT THE SAME TIME.
3
2
leak channels and ion pumps complement each other to maintain a constant ______ _______ and level of ion
electrical potential
concentration
the resting membrane potential voltage is determined by the concentration of _____ charged ions on either side of the membrane. established primarily by?
electrically charged
leak channels
there are more _____ leak channels then _____
Potassium
sodium
the Na+ -K+ pump moves more ____ then ____ in
NA
PA
because the resting membrane is negative on the inside and positive on the outside it is considered to be ______
polarised
the voltage created by this resting distribution of ions is known as the
membrane potential
