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33 Cards in this Set

  • Front
  • Back
what channel does water utilize to get into the cell?
how does Na+/K+ transporter work?
antiport, it does 3 Na+ for every 2 K+ and costs 1 atp
Which ions are in high concentration outside of the cell?
Na++, Ca++, and Cl-
Which are in high concentrations inside of cell?
Proteins (negative charge), K+, Po4^-2
what is average membrane potential in a nerve and in a muslce?
-70 to -80 mV in a nerve & about -90 mV in a muscle cell
a membrane is much more permeable to either potassium or sodium? how much?
much more permeable to potassium, almost 100x. This makes it effect resting membrane potential more
-70 mV to -50 mV is how strong of a graded potential?
20 mV
how many gates does a voltage gated Na+ chanel have?
two, an activation and an inactivation gate
which goes faster in a Na+ channel, activation or inactivation gate?
the activation gate opens almost insantly, the inactivation gate closes slowly
can another action potential cause the inactivation gate to pop back open?
What does the potassium gate look like and how does it work?
it only has ONE gate, which begins opening SLOWLY as soon as threshhold is reached
hwat does tetrodotoxin do?
blocks sodium channels, toxin in a puffer fish
tetraethlammonium ion can do what?
block K+ channels
onset of action potential, Na+ conduction increases
5000 fold
repolarizaiotion, up to ___ fold increase for K+
during the relative refractory period
some inactivation gates on Na are still shut, Voltage-gated K+ channels are ?????? contradiction in my own slide notes
Why is saltatory conduction so effective?
the pumps have to work less, less total ion transfer.

repolarization can occur faster by 5-50fold
myelenation and ____ both determine conduction speed.

how does the second factor effect it?
larger diameter axons conduct an action potential faster than smaller diameter axons
what determines the strength of an action potential?
only the FREQUENCY==="all or none"
electrical synapses use
gap junctions in cardiac and smooth muscle
chemical synapses go
neuron o neuoron, neuron to muscle, neuron to gland, etc

when is neurotransmitter released into the synapse?
when ca++ enters the synaptic knob
What does tetanus toxin do?
it prevents the release of inhibitory transmitter
Strychnine ---->
competes at the postsynaptic receptor site, can lead to convulsions, muslce spasticity, and death
inhibits dopamine destruction in the synapse resulting in prolonged activation of nerons in the reward center of your brain
describe a neuromuscular junction
one nerve fiber branches and stimulates 3 - hundreds of skeletal muscle fibers
where are neuromuscular junctions found? how many

can they be inhibitory?
one per muscle fiber, near the midpoint

motor end plate contains MANY
synaptic space is how wide? contains what?
20-30 nm, contains acetylcholinesterase
subneural cleft
little folds that increase surface area
synaptic vesicles originate in the ____ and travel to the motor end plate

They absorb ____

300,000 per endlate each containing _____ molecules of _____
cell body, acetylchoine, 10,0000
What prompts acetyl choline vesicles to move to the cell membrance, fuse and exotyse?
when a nerve impluse gets to the dense bar and Ca+ rushes in
The gate on a muscle cell is activated by _____

It has 5 subunits, both alpha subunits must be activated for the channel to open

what can pass through it?
acetylcholine, just about anything.