Chapter 2

Question 1

excitatory postsynaptic potential

Answer 1

graded depolarization

Question 2

inhibitory postsynaptic potential

Answer 2

temporary hyperpolarization of a membrane

Question 3

postsynaptic neuron

Answer 3

neuron that receives transmission from another neuron

Question 4

presynaptic neuron

Answer 4

neuron that delivers transmission to another neuron

Question 5

reflex arc

Answer 5

circuit from sensory neuron to muscle response

Question 6

spatial summation

Answer 6

combination of effects from two or more synapses onto a single neuron

Question 7

spontaneous firing rate

Answer 7

periodic production of action potentials without synaptic input

Question 8

synapse

Answer 8

gap as a point of communication between two neurons chemically

Question 9

temporal summation

Answer 9

effect of repeated stimuli within a brief time

Question 10

acetylcholine

Answer 10

modified amino acid

Question 11

amino acids

Answer 11

glutamate, GABA, glycine, aspartate

Question 12

amphetamine

Answer 12

drug that blocks reuptake of dopamine

Question 13

autoreceptors

Answer 13

receptor on presynaptic neuron that provide negative feedback by responding to the released transmitter by inhibiting further release

Question 14

cannabinoids

Answer 14

excites negative-feedback receptors on presynaptic cells

Question 15

catecholamines

Answer 15

dopamine, norepinephrine, epinephrine

Question 16

exocytosis

Answer 16

release of neurotransmitter from presynaptic neuron into synaptic cleft

Question 17

g protein

Question 18

gap junction

Answer 18

direct contact of one neuron with another, enabling electrical transmissions

Question 19

ionotropic effects

Answer 19

synaptic effect that depend on rapid opening of a gate in the membrane

Question 20

ligand-gated channels

Answer 20

channel that opens when a neurotransmitter attaches to it

Question 21

metabotropic effects

Answer 21

sequence of metabolic reactions that produce slow, long-lasting effects

Question 22

methylphenidate

Answer 22

stimulant drug prescribed for ADHD that increases the stimulation of dopamine synapses by blocking the reuptake of dopamine by the presynaptic neuron

Question 23

monoamines

Answer 23

chemicals formed by a change in certain amino acids, catecholamines or indoleamines

Question 24

neuropeptides

Answer 24

chain of amino acids: endorphins, substance P, neuropeptide Y

Question 25

nitric oxide

Answer 25

a gas released by many small local neurons

Question 26

pituitary gland

Answer 26

an endocrine gland attached to the base of the hypothalamus

Question 27

purines

Answer 27

ATP, adenosine

Question 28

releasing hormones

Answer 28

hormone released by the hypothalamus that flows through the blood to the anterior pituitary

Question 29

reuptake

Answer 29

reabsorption of a neurotransmitter by the presynaptic terminal

Question 30

second messenger

Answer 30

a chemical that, when activated by a neurotransmitter, initiates communication to many areas within the neuron

Question 31

synaptic cleft

Answer 31

the space between the presynaptic and postsynaptic neurons

Question 32

transmitter-gated channels

Answer 32

ion channel that opens temporarily when a neurotransmitter binds to it

Question 33

vasopressin

Answer 33

antidiuretic hormone released by posterior pituitary, raises blood pressure and enables kidneys to conserve water

Question 34

vesicles

Answer 34

tiny nearly spherical packets filled with neurotransmitter molecules

Question 35

what evidence led sherrington to conclude that transmission at a synapse is not the same as transmission along an axon?

Answer 35

the velocity of conduction through a reflex arc is slower than the velocity of an action potential along an axon, a delay must occur at the junction between two neurons

Question 36

what ion gates in the membrane open during an EPSP?

Answer 36

sodium gates open

Question 37

what gates open during an IPSP?

Answer 37

chloride gates open

Question 38

what was sherrington’s evidence for inhibition in the nervous system?

Answer 38

a reflex that stimulates a flexor muscle prevents contraction of the extensor muscles of the same limb, sherrington inferred that an interneuron that excites one set of motor neurons inhibits the input to another set

Question 39

can an inhibitory message flow along an axon?

Answer 39

no, only action potentials propagate along an axon, inhibitory messages decay over time and distance

Question 40

sherrington based his conclusions on what type of evidence?

Answer 40

observations of reflexive responses

Question 41

what was loewi’s evidence that neurotransmission depends on the release of chemicals?

Answer 41

when loewi stimulated a nerve that increased or decreased a frog’s heart rate, he could withdraw fluid from the area around the heart, transfer it to another frog’s heart, and thereby increase or decrease its rate also

Question 42

indoleamines

Answer 42

serotonin

Question 43

across species, how much do neurotransmitters vary?

Answer 43

most animals have all or nearly all the same neurotransmitters

Question 44

when the action potential reaches the presynaptic terminal, which ion must enter the presynaptic terminal to evoke release of the neurotransmitter?

Answer 44

calcium

Question 45

ionotropic synapses are most important for what types of behavior?

Answer 45

most important when precise timing is important, visual or auditory perception

Question 46

how do LSD and opiate drugs influence behavior?

Answer 46

LSD binds to one type of serotonin receptor, opiates bind to endorphin receptors

Question 47

what happens to acetylcholine molecules after they stimulate a postsynaptic receptor?

Answer 47

enzyme acetylcholinesterase breaks acetylcholine molecules into two smaller molecules, acetate and choline. The presynaptic neuron then reabsorbs the choline

Question 48

what happens to serotonin and catecholamine molecules after they stimulate a postsynaptic receptor?

Answer 48

most serotonin and catecholamine molecules are reabsorbed by the presynaptic terminal, some of their molecules are broken down into inactive chemicals, which then diffuse away

Question 49

how do amphetamine and cocaine influence synapses?

Answer 49

they block reuptake of released dopamine, serotonin, and norepinephrine

Question 50

why is methylphenidate generally less disruptive to behavior than cocaine, despite the drugs’ similar mechanisms?

Answer 50

the effects of a methylphenidate pill rise and fall more slowly than those of cocaine

Question 51

how do cannabinoids affect neurons?

Answer 51

cannabinoids released by the postsynaptic neuron attach to receptors on presynaptic neurons, where they inhibit further release of both glutamate and GABA

Question 52

nicotine

Answer 52

mimics effect of acetylcholine, which increases dopamine release

Question 53

MDMA (ecstasy)

Answer 53

releases dopamine, serotonin, and norepinephrine

Question 54

which part of the pituitary is neural tissue, similar to the hypothalamus? which part is glandular tissue and produces hormones that control the secretions by other endocrine organs?

Answer 54

the posterior pituitary is neural tissue like the hypothalamus, the anterior pituitary is glandular tissue and produces hormones that control several other endocrine organs

Question 54

what do releasing hormones do?

Answer 54

hypothalamus secretes releasing hormones, which control release of hormones by the pituitary gland

Question 55

brain excitatory neurotransmitter

Answer 55

glutamate

Question 55

brain inhibitory neurotransmitter

Answer 55

GABA

Question 56

what happens when a neurotransmitter binds to a metabotropic receptor?

Answer 56

bends the receptor protein