Topic 11

Question 1

Action potential

Answer 1

All or nothing signal or communication event, generated by an eletrially active cell (neurons or muscles)

Question 2

Depolarized

Answer 2

moving away from the polarized state, and movs to more neutral

Question 3

Repolarization

Answer 3

moves back towards the negative starting pole

Question 4

Hyperpolization

Answer 4

moves polarity start past the starting and makes membrane event even more negative than what it started with

Question 5

Threshold

Answer 5

minumum voltage change needed to start an action potential

Question 6

Voltage-gated ion channel

Answer 6

the protein transport channels are specific to certain ions (Na+, K+, etc.) Voltage gated means that the proteins respond to voltage along the membrane

Question 7

Steps of Action potential

Answer 7

1. Resting membrane potential
   2.Slow depolarization
2. Fast Depolarization
   4.Repolarization
   4b. Threshold
3. Hyperpolarization
4. Resting membrane potential

Question 8

Phase 1 A.P

Answer 8

Resting Membrane Potential
-All voltage-gated channels are closed
-ATPase and leak channels have stabilized the membrane voltage arond -70mV

Question 9

Events during Phase 2 & 3 A.P

Answer 9

Slow Depolarization to Fast Depolarization
-Voltage-gated Na+ channels are open
-Intially a few of the voltage-gated Na+ channels open
-Sodium moves into cell, membrane depolarizes
-Threshold: when there is enough of a voltage change along the membrane, it trips the remaining voltage-gated Na+ channels to open, moving into fast depolarization

Question 10

Events at the end of Phase 3 and start of phase 4

Answer 10

Fast Depolarization into Repolarization
-voltage-gated sodium channels have closed, no longer to open again (at least until reset)
-Voltage gated potassium channels have opened, potassium flows out of the cell, taking positive charges with it, causes the interior along membrnae to retrun to a more genitive state (repolarizes)

Question 11

Phase 4 into 5

Answer 11

Repolarization into Hyperpolarization
Voltage-gated K+ channels are open

Question 12

Phase 5 into 6

Answer 12

Hyperpolarization to Resting membrane potential
-All voltage-gated K+ channels closed but slow to close, so a little too much potassium (positive) leaves, causing the mmebrnae to overshoot its negative (-70 mV pole, and becomes hyperpolarized)
Phase 6:
Na+/K+ ATPase pumps, and leak channels restoring the resting state

Question 13

Conduction

Answer 13

wave of voltage change that sweeps down the axon, but it doesn’t actually carry any physical moleule with it. The voltage change serves as the signal

Question 14

Refractory period

Answer 14

period of time when the voltage-gated sodium channels have already been triggered and they aren’t in their ready to respond position anymore, but their gates are closed

Question 15

Saltatory Conduction

Answer 15

jumping movement of the action potential from node (no myelin along the axon) to node

Question 16

Myelinated axon

Answer 16

conduct signals much faster thn unmyelinated, diameter of the axon also influences the speed that signals are moved (larger diameter increase speed of signal are moved (larger diameter increase speed of the signal)

Question 17

Unmyelinated axon

Answer 17

neurons with diameters that is 2mm wide

Question 18

Synaptic Transmission

Answer 18

A process where one neuron relays a signal to target cell

Question 19

Synaptic Signaling

Answer 19

Presynaptic (signaling) cell) sends the message through the flow of information and between the gap (cleft) to the postsynaptic (target) cell