Lecture 11.6-11.10

Question 1

Action potential (AP)

Answer 1

a wave of electrical activity traveling down a nerve or muscle fiber, allowing the body to communicate

Question 2

Nerve impulse

Answer 2

AP in neuron,

Question 3

Generating an AP

Answer 3

Resting state
Depolarization
Repolarization
Hyperpolarization

Question 4

Resting state

Answer 4

inside of the neuron is more negative compared to the outside

Voltage-gated Na⁺ (sodium) and K⁺ (potassium) channels are closed

neuron is polarized

Question 5

polarized

Answer 5

there’s a voltage difference across the membrane.

Question 6

Depolarization

Answer 6

neuron gets a strong enough signal

voltage-gated Na⁺ channels open

allows Na⁺ ions to rush into the neuron

the inside of the neuron becomes more positive and the membrane potential becomes less negative, eventually becoming positive.

Question 7

Repolarization

Answer 7

Na⁺ channels close

voltage-gated K⁺ channels open

As K⁺ leaves, the inside of the neuron becomes negative again, returning toward the resting membrane potential.

Question 8

Hyperpolarization

Answer 8

some of the K⁺ channels remain open a bit longer, causing the inside of the neuron to become even more negative than the resting potential

Na⁺ channels reset

neuron eventually returns to its resting state

Question 9

threshold

Answer 9

minimum level of stimulation needed to trigger an action potential

Question 10

all or none phenomenon

Answer 10

If the stimulus is strong enough to reach the threshold, the neuron fires a complete action potential. If it’s too weak, the neuron does nothing

Question 11

Synapse

Answer 11

junction that mediates information transfer from one neuron to the next

Question 12

Electrical synapses

Answer 12

Provide a simple means of synching the activity of all the connected neurons

connect the cytoplasm of closeby neurons

allow neurons to move from one neuron to the next, they are electrically coupled

More abundant in embryonic tissue

Question 13

Chemical synapses

Answer 13

Allow release and reception of chemical messengers aka neurotransmitters

To transport impulses, it must be done through chemical event that depends on release

Question 14

2 parts of Chemical synapses

Answer 14

Axon terminal: holds sacs called synaptic vesicles,

Receptor region: a neurotransmitter

Question 15

Synaptic delay

Answer 15

amount of time it takes for a signal to travel from one neuron to another across a synapse

Question 16

Excitatory synapses

Answer 16

makes the next neuron more likely to fire an action potential.

Question 17

Excitatory synapses process

Answer 17

AP reaches excitatory synapse

neurotransmitters are released and bind to the receptors of the other neuron

Na+ ions flow into the neuron, making it more +

Neuron is now closer to threshold to trigger the next AP

Question 18

ESPS

Answer 18

a small, temporary change in the membrane potential that makes the neuron more likely to fire

Question 19

Inhibitory synapses

Answer 19

Reduces ability to generate AP

neurotransmitters bind to receptors on the receiving neuron, causing chloride (Cl-) ions to flow into the neuron, or potassium (K+) ions to flow out.

makes the inside of the neuron more negative

pushes the neuron further away from the threshold needed to trigger an AP

Question 20

ISPS

Answer 20

a small, temporary change in the membrane potential that makes the neuron less likely to fire

Question 21

Neurotransmitters

Answer 21

means by which neurons communicate, integrate, and send messages to the rest of the body.

Question 22

Acetylcholine

Answer 22

released by all neurons

Released by presynaptic terminal → binds to postsynaptic receptors → released and degraded to acetic acid and choline by acetylcholinesterase → presynaptic terminals recapture the released choline and reuse it to synthesize more ACh

Question 23

Biogenic Amines

Answer 23

Catecholamines → dopamine, norepinephrine, epinephrine
Indolamines → serotonin and histamine

broadly distributed in the brain

Question 24

Amino Acids

Answer 24

glutamate, aspartate, glycine, and gamma aminobutyric acid (GABA).

Question 25

Peptides

Answer 25

Neuropeptides: strings of amino acids

Substance P: important mediator of pain signals

Endorphins: beta endorphin, dynorphin, and enkephalins, act as natural opiates, reducing the perception of pain under stressful conditions

Gut-brain peptides: widespread in the gastrointestinal tract

Question 26

Purines

Answer 26

Nitrogen containing base that makes up DNA and RNA

ATP is recognized as a major neurotransmitter in both the CNS and PNS

ATP mediates Ca2+ influx upon binding to receptors on astrocytes

Adenosine is a potent inhibitor in the brain

Question 27

Gastotransmitters

Answer 27

Include: nitric oxide, carbon monoxide, and hydrogen sulfide

Synthesized on demand and diffuse out of the cells that make them

Question 28

Endocannabinoids

Answer 28

tetrahydrocannabinol (THC), active ingredient in marijuana