Chapter 4: Neuronal Signaling

Question 1

what did Galviani study?

Answer 1

the reflexive responses of dissected frog legs to electrical responses

Question 2

what are cations?

Answer 2

positively charged ions (sodium and potassium)

Question 3

what are anions?

Answer 3

negatively charged ions (chloride)

Question 4

voltage gradient

Answer 4

positive and negative ions will flow down their electrostatic gradients until positive and negative charges are equal everywhere

Question 5

ungated channel

Answer 5

ions can cross a cell membrane through the appropriately shaped channel

Question 6

gated channel

Answer 6

changes shape to allow the passage of substances when gates are open and to prevent passage when one or both gates are closed

Question 7

what is the resting potential?

Answer 7

a store of negative energy inside the neuron membrane relative to the outside (-70mV)

Question 8

what is the purpose of the sodium-potassium pump?

Answer 8

helps maintain resting potential in the cell by pumping Na+ from inside the cell and exchanges it for K+ from outside the cell

Question 9

what causes hyperpolarization?

Answer 9

an efflux of K+, which makes the extracellular side of the membrane more positive, or an influx of Cl-

Question 10

what causes depolarization?

Answer 10

an influx of Na+ through Na+ channels

Question 11

how does an action potential start?

Answer 11

voltage-gated Na+ channels burst open a fraction sooner than gated K+ channels when the membrane receives enough stimulation, causing K+ ions to rush out of the cell

Question 12

what is the all-or-nothing law?

Answer 12

the magnitude of the action potential remains consistent all the way down the axon terminal

Question 13

what is saltatory conduction?

Answer 13

the current flow jumps over the nodes of ranvier, speeding up the conduction of the signal along the axon

Question 14

excitatory postsynaptic potential

Answer 14

depolarizes the postsynaptic neuron

Question 15

inhibitory postsynaptic potential

Answer 15

hyperpolarizes the postsynaptic neuron

Question 16

deep brain stimulation

Answer 16

electrodes are implanted deep in the brain and stimulate targeted areas with a low-voltage electrical current to facilitate behaviour

Question 17

what did Otto Loewi do?

Answer 17

stimulated the vagus nerve of a frog heart and measured the effects on heart rate.
discovered acetylcholine

Question 18

what are the criteria for identifying neurotransmitters?

Answer 18

1. chemical must be synthesized or present in the neuron
2. when released, the chemical must produce a response in the target cell
3. same receptor action must be obtained when the chemical is experimentally placed on the target
4. there must be a mechanism for removal after the chemical’s work is done

Question 19

presynaptic membrane

Answer 19

encloses molecules that transmit chemical messages

Question 20

synaptic cleft

Answer 20

small space separating presynaptic terminal and postsynaptic dendritic spine

Question 21

postsynaptic membrane

Answer 21

contains receptor molecules that receive chemical messages

Question 22

microtubule

Answer 22

transport structure that carries substances to the axon terminal

Question 23

synaptic vesicle

Answer 23

round granule that contains neurotransmitters

Question 24

storage granule

Answer 24

large compartment that holds synaptic vesicles

Question 25

postsynaptic receptor

Answer 25

site to which a neurotransmitter molecule binds

Question 26

what are the steps of neurotransmission?

Answer 26

1. synthesis 2. release 3. receptor action 4. inactivation

Question 27

what does calcium serve as?

Answer 27

the signal for vesicles to release their neurotransmitters into the axon terminal

Question 28

what is the purpose of autoreceptors?

Answer 28

allows the neuron to keep track of how much neurotransmitter has been released and when to stop

Question 29

what is the purpose of ionotropic receptors?

Answer 29

can depolarize or hyperpolarize the cell and can change the electrical charge in the receiving neuron

Question 30

what is the structure of a metabotropic receptor?

Answer 30

embedded membraine protein with a binding site for a neurotransmitter but no pore

Question 31

what is the purpose of a metabrotropic receptor?

Answer 31

activates a G-protein that can signal a second messenger

Question 32

what do second messengers promote? what does this result in?

Answer 32

DNA transcription in pre and postsynaptic neurons. results in structural changes that strengthen the signals between two neurons

Question 33

which neurotransmitter is present in the cholinergic system?

Answer 33

acetylcholine

Question 34

which brain structures make up the cholinergic system?

Answer 34

midbrain and basal forebrain

Question 35

what is the cholinergic system involved in?

Answer 35

learning and memory through its effects on attention

Question 36

which neurotransmitter is present in the dopaminergic system?

Answer 36

dopamine

Question 37

what are the two main pathways in the dopaminergic system?

Answer 37

mesolimbic pathway (nucleus accumbens) and nigrosriatal pathway (substantia nigra)

Question 38

what is the mesolimbic pathway involved in?

Answer 38

reward; habit formation

Question 39

what is the nigrostriatal pathway involved in?

Answer 39

moderates movement

Question 40

which neurotransmitter is present in the noradrenergic system?

Answer 40

norepinephrine

Question 41

what does the noradrenergic system control?

Answer 41

the sympathetic nervous system (fight or flight) increases energy and heart rate

Question 42

which neurotransmitter is present in the serotonergic system?

Answer 42

serotonin

Question 43

what does the serotonergic system control?

Answer 43

mood and emotion, appetite and digestion, sleep cycles

Question 44

what is GABA?

Answer 44

the most inhibitory neurotransmitter in the body. slows you down

Question 45

what is glutamate?

Answer 45

the most numerous neurotransmitter in the body due to it being involved in so many things. most excitatory neurotransmitter in the body