Week 1 - Neurons Worksheets Flashcards
The sodium-potassium pump transports –
K+ into the neuron
Na+ out of the neuron
In the resting state of the neural membrane, diffusion due to concentration gradients, if allowed, would drive -
Na+ into the cell
An Action Potential for a given axon is
always the same size
What increases when an action potential is first initiated?
Diffusion of sodium ions into the neuron
The primary function of the myelin sheaths around an axon is to -
increase the speed of conduction of the impulse
In the resting state of the axon, the steady voltage difference across the plasma membrane, called the _______________, is typically ____________.
Resting membrane potential
-70mV
An action potential is initiated each time the membrane potential is raised to what level?
Threshold
Because AP never occur below the threshold level and upon occurring always display the same ____________, action potentials are said to be ________ or __________- events
characteristics
all or none
Action potentials travel in one direction only along an axon because behind the potential the membrane is in a brief _________ ___________ period when it is insensitive to new simulation.
Absolute Refractory period
When a membrane potential known as an EPSP develops in the postsynaptic membrane, it —
increases the likelihood of an AP in the postsynaptic neuron
The NT released into the synapse between neurons and muscle cells that produces an EPSP in skeletal muscle cells is:
a. GABA
b. ACh
c. norepinephrine
d. epinephrine
b. Ach
acetylcholine
When an AP reaches a vertebrate chemical synapse, it opens ___1.___ channels in the plasma membrane of the synaptic bulb, permitting this ion to diffuse into the bulb.
This in turn, causes ___2.____ containing NT to fuse with the ______ 3. ____ and release the NTs into the ___4.__.
The NT then diffuse to the _____5.____ _____, where they interact with __6. __; this interaction produces either an ___7.___ or an ___8.___
- calcium channels
- synaptic vesicles
- presynaptic membrane
- synapse
- postsynaptic membrane
- receptors
- EPSP
- IPSP
What are the major functions of the NS
receiving and sending signals
Where is most of the sodium and potassium found - inside or outside the nerve cell membrane?
Sodium out
Potassium in
Where do you find the net positive charge in relation to a nerve cell?
Inside or outside cell the cell?
A little negative in
A little positive out
net positive charge outside the cell
