ACTION POTENTIAL

Question 1

regular motor neuron

Answer 1

• 2 msec immediate reaction e.g. in boxing

Question 2

skeletal muscle motor neuron

Answer 2

• 5 msec immediate reaction eg in boxing

Question 3

cardiac ventricle action potential

Answer 3

• 200 msec

- due to blood to flow and eject

Question 4

potassium leave the cell negative also with

Answer 4

• chloride because it is also negative

Question 5

action potential predominantly related to

Answer 5

• Na influx

Question 6

tetrodotoxin

Answer 6

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

Question 7

too much repolarization will cause

Answer 7

• hyperpolarization

Question 8

sub threshold potential change

Answer 8

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

Question 9

action potential

Answer 9

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

Question 10

ungated

Answer 10

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

Question 11

voltage gated channels

Answer 11

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

Question 12

conductance

Answer 12

• ions in and out of the cell

Question 13

depolarization

Answer 13

• opening of voltage-gated Na channels

Question 14

repolarization

Answer 14

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

Question 15

major conductance of K

Answer 15

• out of the cell

- efflux

Question 16

major conductance of Na

Answer 16

• into the cell

- influx

Question 17

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

Answer 17

• dead tissue

Question 18

Na goes IN (+)

Answer 18

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

Question 19

absolute refractory period

Answer 19

• 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

Question 20

relative refractory period

Answer 20

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

Question 21

Na channel closed

Answer 21

• stop depolarizing

Question 22

K leaves the cell

Answer 22

• depolarized back to normal

Question 23

K continous to leave

Answer 23

• hyperpolarization

Question 24

important factors of action potential

Answer 24

• size of the action potential
• cell diameter
• myelination- insulation conduct more lose a lot of energy, more conduction
• demyelination

Question 25

neuromuscular junction released

Answer 25

- calcium released Ach - Ach makes action potential at the neuromuscular junction - sodium goes in - potassium goes out

Question 26

ligand

Answer 26

- special protein

Question 27

neuromuscular transmission

Answer 27

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

Question 28

more myelin and thicker axons

Answer 28

- faster the conductance

Question 29

vesicles release

Answer 29

- Ach

Question 30

transmitter that generate EPSP (excitatory)

Answer 30

- Ach- excitatory - glutamate- stimulatory - aspartate- stimulatory

Question 31

transmitter that generate IPSP (inhibitory) produced by increase conductance to Cl- into the cell

Answer 31

- glycine | - GABA

Question 32

myasthenia gravis

Answer 32

- disease in the neuromuscular junction - defect of Ach receptor - ssx double vision - difficulty chewing