Neurotransmission

Question 1

what does the phospholipid bilayer prevent?

Answer 1

ion exchange

Question 2

what regulates the movement of ions?

Answer 2

ion channels

Question 3

what are the main ion specific channels?

Answer 3

sodium, potassium, chloride channels

Question 4

what is the membrane potential?

Answer 4

the difference in electrical charge between the inside and outside of the neuron

Question 5

what will change the membrane potential?

Answer 5

movement of ions through the channels

Question 6

what is the membrane potential of the average neuron?

Answer 6

-65mV

Question 7

depolarization occurs when…

Answer 7

the membrane potential becomes more positive

Question 8

hyperpolarization occurs when…

Answer 8

the membrane potential becomes more negative

Question 9

what are the two ion gradients?

Answer 9

concentration and electrical

Question 10

what is equilibrium potential?

Answer 10

when the flow of ions in and out has the same pull

Question 11

which gradients is sodium drawn in by?

Answer 11

electrical and concentration

Question 12

what is the equilibrium potential of Na+?

Answer 12

+60mV

Question 13

what is the equilibrium potential of K+?

Answer 13

-85mV

Question 14

what is the equilibrium potential of Cl-?

Answer 14

-65mV

Question 15

which gated ion channels are open at rest?

Answer 15

mostly K+, half as many Cl-, very very few Na+

Question 16

what is the sodium potassium pump?

Answer 16

ATP activated pump that moves 3 Na+ out of the cell and 2 K+ into the cell

Question 17

what happens if there is an excitatory postsynaptic potential?

Answer 17

sodium channels open and will come into the cell to cause depolarization

Question 18

what happens if there is an inhibitory postsynaptic potential?

Answer 18

chloride channels open and decrease the likeliness of depolarization

Question 19

what is temporal summation?

Answer 19

when the stimulus is applied repeatedly in succession from one input

Question 20

what is spatial summation?

Answer 20

when many stimulus are applied from multiple input sources?

Question 21

what happens when the membrane potential decreases past threshold (-50mV)?

Answer 21

creates a sudden opening of voltage gated sodium channels (rising phase)

Question 22

what happens after the rising phase?

Answer 22

falling phase
sodium channels are deactivated and voltage gated potassium channels are active, causes rapid repolarization

Question 23

what returns the neuron back to its resting membrane potential after the falling phase?

Answer 23

the falling phase undershoots, Na+K+ pump rises the membrane potential back to resting

Question 24

what is the absolute refractory period?

Answer 24

time after the membrane potential has crossed the threshold when another action potential cannot begin

Question 25

when will sodium channels reopen?

Answer 25

when the membrane potential is below threshold

Question 26

what is the relative refractory period?

Answer 26

potassium channels remain open for a moment to undershoot the resting membrane potential, requires a stronger stimulus to reach threshold

Question 27

how is the action potential released?

Answer 27

progressively along the axon

Question 28

what helps increase the rate of impulse?

Answer 28

thicker myelin, larger axons

Question 29

what are nodes of Ranvier

Answer 29

gaps between myelin

Question 30

what are signals traveling along the nodes of Ranvier called?

Answer 30

saltatory conduction

Question 31

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

Answer 31

neurotransmitters are released

Question 32

when will a postsynaptic neuron start an action potential?

Answer 32

when enough neurotransmitters reach the receptors on the postsynaptic membrane

Question 33

neurotransmitters

Answer 33

can be inhibitory, excitatory, or neuromodulatory some have different effects on different receptors multiple neurotransmitters can be released within a single synapse

Question 34

what are neurotransmitters composed of?

Answer 34

molecules or amino acids

Question 35

glutamate

Answer 35

most common excitatory neurotransmitter found and acts throughout CNS allows Na+ into membrane, leads to depolarization

Question 36

histamine effect

Answer 36

excitatory, neuromodulatory function

Question 37

gamma-aminobutyric acid (GABA)

Answer 37

most common inhibitory neurotransmitter found and acts throughout CNS allows Cl- through membrane

Question 38

glycine action and location

Answer 38

inhibitory found in and acts on the spinal cord, acts on the brainstem

Question 39

what do neuromodulators do?

Answer 39

change how neurons function: change firing rate synaptic efficacy +/- currents

Question 40

dopamine location

Answer 40

substantia nigra and ventral tegmental area

Question 41

serotonin location

Answer 41

raphe nuclei

Question 42

where is histamine found

Answer 42

hypothalamus and reticular formation

Question 43

norepinephrine location

Answer 43

sympathetic ganglia and locus ceruleus

Question 44

where are neuropeptides found

Answer 44

entire CNS

Question 45

acetylcholine

Answer 45

primary neurotransmitter in neuromuscular junctions

Question 46

what kind of synapses does Ach have?

Answer 46

preganglionic autonomic and postganglionic parasympathetic

Question 47

where does Ach have a neuromodulator effect?

Answer 47

in small areas of the CNS