ACTION POTENTIAL Flashcards
1
Q
regular motor neuron
A
- 2 msec immediate reaction e.g. in boxing
2
Q
skeletal muscle motor neuron
A
- 5 msec immediate reaction eg in boxing
3
Q
cardiac ventricle action potential
A
- 200 msec
- due to blood to flow and eject
4
Q
potassium leave the cell negative also with
A
- chloride because it is also negative
5
Q
action potential predominantly related to
A
- Na influx
6
Q
tetrodotoxin
A
- paralyzed positive and negative charges in neuron muscular junction
- freeze neural transmission
- no depolarization
7
Q
too much repolarization will cause
A
- hyperpolarization
8
Q
sub threshold potential change
A
- proportional stimulus
- not propagated but decremental with distance
- EXHIBITS SUMMATION (multiple stimulus)
9
Q
action potential
A
- independent of stimulus
- propagated unchanged in magnitude
- SUMMATION NOT POSSIBLE
- DOWNHILL
10
Q
ungated
A
- continous
- based on concentration gradient
- not affected by action potential
- not based on charge
- not affected by gradient
11
Q
voltage gated channels
A
- create the concentration difference
- not continuous
- affected by action potential
12
Q
conductance
A
- ions in and out of the cell
13
Q
depolarization
A
- opening of voltage-gated Na channels
14
Q
repolarization
A
- voltage gated Na channel are rapidly closing
- voltage gated K are still opening increasing K+ conductance
- Na/K-ATPase pump
15
Q
major conductance of K
A
- out of the cell
- efflux
16
Q
major conductance of Na
A
- into the cell
- influx
17
Q
neural tissue that is equal outside and equal inside/ steady state
A
- dead tissue
18
Q
Na goes IN (+)
A
- the voltage becomes more positive of the interior of the cell
- depolarization
19
Q
absolute refractory period
A
- functional refractory period
- no matter how strong the stimulus it cannot induce as second action potential
- due to voltage inactivation of SODIUM channels
- actual depolarization and repolarization
20
Q
relative refractory period
A
- greater than normal stimulus is required to induce a second action potential
- hyper polarized then preparing for repolarization
21
Q
Na channel closed
A
- stop depolarizing
22
Q
K leaves the cell
A
- depolarized back to normal
23
Q
K continous to leave
A
- hyperpolarization
24
Q
important factors of action potential
A
- size of the action potential
- cell diameter
- myelination- insulation conduct more lose a lot of energy, more conduction
- demyelination
25
neuromuscular junction released
- calcium released Ach
- Ach makes action potential at the neuromuscular junction
- sodium goes in
- potassium goes out
26
ligand
- special protein
27
neuromuscular transmission
action potential travels down to
axon
ends in the presynaptic motor axon terminal
opens voltage-gated calcium channels
2 part
increase in Ca2+ permeability of the axon terminal
causes influx of extracellular Ca2+
into the axon terminal
3rd part
rise in intracellular free Ca2+ causes release of Ach
from synaptic vesicles
into the synaptic cleft
4th part
diffusion of Ach to post junctional membrane
5th part
combination of Ach with cholinergic nicotinic receptor on the post junctional membrane
6th part
opening of ligand dependent channels
result in increased conductance to Na+ and K+
7th part
influx of Na+ causes local depolarization of post junctional membrane
8th part
EPP (end plate potential) spreads
causing depolarization of areas of muscle membrane adjacent to end plate
28
more myelin and thicker axons
- faster the conductance
29
vesicles release
- Ach
30
transmitter that generate EPSP (excitatory)
- Ach- excitatory
- glutamate- stimulatory
- aspartate- stimulatory
31
transmitter that generate IPSP (inhibitory) produced by increase conductance to Cl- into the cell
- glycine
| - GABA
32
myasthenia gravis
- disease in the neuromuscular junction
- defect of Ach receptor
- ssx double vision
- difficulty chewing
