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Flashcards in ACTION POTENTIAL Deck (32):
1

regular motor neuron

- 2 msec immediate reaction e.g. in boxing

2

skeletal muscle motor neuron

- 5 msec immediate reaction eg in boxing

3

cardiac ventricle action potential

- 200 msec
- due to blood to flow and eject

4

potassium leave the cell negative also with

- chloride because it is also negative

5

action potential predominantly related to

- Na influx

6

tetrodotoxin

- paralyzed positive and negative charges in neuron muscular junction
- freeze neural transmission
- no depolarization

7

too much repolarization will cause

- hyperpolarization

8

sub threshold potential change

- proportional stimulus
- not propagated but decremental with distance
- EXHIBITS SUMMATION (multiple stimulus)

9

action potential

- independent of stimulus
- propagated unchanged in magnitude
- SUMMATION NOT POSSIBLE
- DOWNHILL

10

ungated

- continous
- based on concentration gradient
- not affected by action potential
- not based on charge
- not affected by gradient

11

voltage gated channels

- create the concentration difference
- not continuous
- affected by action potential

12

conductance

- ions in and out of the cell

13

depolarization

- opening of voltage-gated Na channels

14

repolarization

- voltage gated Na channel are rapidly closing
- voltage gated K are still opening increasing K+ conductance
- Na/K-ATPase pump

15

major conductance of K

- out of the cell
- efflux

16

major conductance of Na

- into the cell
- influx

17

neural tissue that is equal outside and equal inside/ steady state

- dead tissue

18

Na goes IN (+)

- the voltage becomes more positive of the interior of the cell
- depolarization

19

absolute refractory period

- 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

relative refractory period

- greater than normal stimulus is required to induce a second action potential
- hyper polarized then preparing for repolarization

21

Na channel closed

- stop depolarizing

22

K leaves the cell

- depolarized back to normal

23

K continous to leave

- hyperpolarization

24

important factors of action potential

- 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