Nervous system part 2 Flashcards
A change in resting membrane potential can be changed by anything that changes membrane ion permeability (opens or closes ion gates
There are two kinds of changes
____ (local, signal over short distances) small to large changes in membrane potential due to opening and closing of chemical gates
____ membrane potential decreases (closer to threshold)
____ membrane potential increases (away from threshold)
They are given different names depending on where they occur and their functions usually in ____ of dendrites and cell bodies of neurons
Graded potentials
Depolarization (closer to threshold, less negative, but membrane potential decreases)
Hyperpolarization
Receptor region
____
-______ occurs and response is stimulatory
-Might reach threshold and causes an action potential and cell response
____
-____ and response is inhibitory
-Decrease action potentials by furthering membrane potential further from threshold
Excitatory Postsynaptic Potential (EPSP)
Depolarization
Inhibitory Postsynaptic Potential (IPSP)
Hyperpolarization
Excitatory Postsynaptic Potential (EPSP) is NOT an ____ response but is proportionate in size to the strength of the ____
all-or-none
Afferent stimulus
Summations
no summation involved
summation of a repeated stimulation by one neuron, E1 and E1 again
Summation of different complementary stimuli from different neurons together E1 + E2
Summation of contrasting Presynaptic inputs
The trigger zone is called an ____
Subthreshold
Temporal summation
Spatial summation
Spatial Summation of EPSP and IPSP
Axon Hillock
Contrast to the short-distance Graded Potential, the other kind of potential change is ____ which is long-distance
It is rapid and all-or-none change in membrane potential followed by immediate return to resting membrane potential
It is the ____ and ____ of membrane. The last phase is ____
Due to the sequential opening and closing of serveral voltage gates and active transport
___ comes in to depolarize and ____ comes out to repolarize
Action Potential
Complete depolarization and repolarization
Undershoot
Na+
K+
Only ones that can generate action potential is ____ and ___
Action potential is a rapid temporary change in membrane potential that lasts ___
Does not decrease in strength
A succesfully transmitted action potential is called a ___
The only thing able to generate an action potential is a ____
Neurons and Muscle cells
10 ms
nerve impulse
Axon
Action Potential steps
Na+ and K+ channels are closed.
Stimulus opens Na+ channel. Na+ influx inside. Threshold reached if ever
Activation gates on most Na+ channels open. K+ is still closed. Makes inside positive
Na+ channels close. K+ channels reopen. Makes inside negative
Both gates close. Some K+ channels are open.
Resting State
Depolarization
Rising Phase of the Action Potential
Falling phase of the Action Potential
Undershoot
If another threshold stimulus is received, how much time should pass until another action potential is produced?
What is it called?
Ensures that each action potential is separate and enforces one-way transmission of AP
one-third of repolarization is complete
Dead phase (absolute refractory period)
Other terms of Action Potential
___to generate an actional potential an axon requires a stimulus of minimum strength
____ each action potential has the same amplitude independently from strength of stimulus
___ Second action potential cannot occur
Threshold
All or none
Refractory Period
Happens when myelinated fibers make AP movement easier and faster through nodes of ranvier
Saltatory conduction
Saltatory conduction
1 Action potential reaches ____
2 ____ open
3 ____ causes ____ to release neurotransmitter
4 Neurotransmitter crosses ____
5 Neurotransmitter binds to ____
6 Trigger signal in ____
1 Action potential reaches axon terminal
2 Calcium channels open
3 Ca2+ causes vesicles to release neurotransmitter
4 Neurotransmitter crosses synapse
5 Neurotransmitter binds to neuroreceptors
6 Trigger signal in post-synaptic neuron
What causes the vesicles to release the neurotransmitter?
What does the neurotransmitter bind to?
Triggers a signal in ____
Ca2+
Neuroreceptor
post-synaptic neuron
____ cellular junctions where signals are transmitted from neurons to other cells
Target cells (3)
Types of communication junctions (2) via what
Synapses
Other neurons
Muscle cells
Gland cells
Electrical synapses via gap junctions
Chemical synapses involving neurotransmitters
____ Allows a ____ to flow directly from one cell to another and facilitates small molecules
Only a gap of ___ to ___ nm
They are formed where ____ called ____ connect with one between cells p.s o/i subunit
Its bidirectional
Electrical synapses
current
2 to 4 nm
Hexameric pores
Connexons
____ Allow flow of ions between neuron and specialized for the release and reception of neurotransmitters
Gap is ___ nm also known as ____
Unidirectional only
Prevents direct transmission of action potential
Two parts include:
Chemical synapses
30 nm
Synaptic cleft
Axon terminals: Synaptic vesicles
Receptor region of postsynaptic neuron
