1.4 Action Potentials Part 2

Question 1

What does it mean that action potentials are self propagating?

Answer 1

ion channels along axon are prompted to open whenever the membrane potential depolarizes in the surrounding area

Question 2

What does it mean that an action potential is an all or nothing response?

Answer 2

it either occurs or does not occur; no in between

Question 3

Since there is no variation in the strength of an action potential how do we distinguish between severity?

Answer 3

number of neurons firing and the frequency of firing

Question 4

What does it mean that transmission of nerve impulse are electrochemical?

Answer 4

electrical in the axon, chemical in the synapse, back to electrical in the axon

Question 5

What happens when an action potential reaches the end of an axon?

Answer 5

voltage-gated calcium channels open allowing calcium to rush into the axon

Question 6

What does the influx of calcium ions cause at the ends of axons?

Answer 6

causes vesicles that contain neurotransmitters to release the neurotransmitter into the synapse

Question 7

What happens after neurotransmitters are released into the synapse?

Answer 7

sodium channels on the post synaptic neuron open causing a depolarization event

Question 8

What is an example of an enzyme that inactivates a neurotransmitter?

Answer 8

acetylcholinesterase

Question 9

What is needed to prevent continuous stimulation of the postsynaptic membrane?

Answer 9

short existance of neurotransmitter in the synapse

Question 10

What are examples of how some neurons make sure the neurotransmitter only exists for a short while in the synapse?

Answer 10

1. enzymes that degrade the neurotransmitter
2. cells reabsorb the neurotransmitter

Question 11

What are the neurotransmitters produced by the adrenal glands?

Answer 11

epinephrine
norepinephrine

Question 12

What is dopamine?

Answer 12

specialized neurotransmitter that helps regulate emotional responses and muscle tone

Question 13

What is the neurotransmitter found at neuromuscular junctions?

Answer 13

acetylcholine

Question 14

What is a neuromuscular junction?

Answer 14

found in the PNS where a motor neurons meets a muscle

Question 15

Where does the action potential in a muscle cell end up at?

Answer 15

sarcoplasmic reticulum

Question 16

What is the sarcoplasmic reticulum?

Answer 16

specialized smooth ER found within striated muscle tissue

Question 17

What is released from the sarcoplasmic reticulum that causes the muscle to contract?

Answer 17

calcium