Ch3 pt1-Concept of the Synapse

Question 1

communication BETWEEN neurons is primarily…

Answer 1

chemical

Question 2

communication WITHIN neurons is primarily….

Answer 2

electrical

Question 3

specialized gap between neurons

Answer 3

synapse

Question 4

demonstrated communication between one neuron & the next differs from communication along one axon

Answer 4

Charles Scott Sherrington

also coined term synapse

Question 5

automatic muscular responses to stimuli

Answer 5

reflexes

Question 6

circuit from sensory neuron to muscle response

Answer 6

reflex arc

Question 7

Sherrington observed what when studying reflexes on dogs

Answer 7

a) reflexes are slower than conduction along axon
b) several weak stimuli presented at slightly different times or slightly different locations produce stronger reflex than single stimulus does
c) when one set of muscles becomes excited, a different set becomes relaxed

Question 8

speed of conduction through reflex arc was never more than ______ m/sec

Answer 8

15

Question 9

Sherrington validated idea of synapse by

Answer 9

concluding some process was slowing conduction through reflex

Question 10

repeated stimuli within a brief time have a cumulative effect (stronger than single stimuli)

Answer 10

temporal summation

Question 11

cell that RECEIVES message

Answer 11

postsynaptic neuron

Question 12

cell that DELIVERS message

Answer 12

pre-synaptic neuron

Question 13

graded depolarization; occurs when sodium ions enter the cell (decay over space & time; discovered by Eccles)

Answer 13

excitatory postsynaptic potential (EPSP)

Question 14

synaptic inputs from various locations combine their effects on a neuron (critical to brain function)

Answer 14

spatial summation

Question 15

temporal summation & spatial summation ordinarily occur together

Answer 15

just remember that

Question 16

flexor muscles

Answer 16

contract

Question 17

extensor muscles

Answer 17

extend

Question 18

at inhibitory synapse, input from an axon ______ the postsynaptic cell

Answer 18

hyperpolarizes

Question 19

occurs when the synaptic input selectively opens the channel for potassium ions to leave the cell or for chloride ions to enter the cell

• come from temporary hyperpolarization
• serves as active “break” away from excitation

Answer 19

Inhibitory postsynaptic potential (IPSP)

Question 20

importance of Sherrington’s work

Answer 20

researchers can show how nervous system is wired & design systems based on this

Question 21

periodic reproduction of action potentials even without synaptic input

Answer 21

spontaneous firing rate

Question 22

which 2 individuals were apart of discovering chemical synapses

Answer 22

Elliot then Loewi

Question 23

chemicals released by one neuron that affect a second neuron

Answer 23

neurotransmitter

Question 24

what are the types of neurotransmitters

Answer 24

amino acids, neuropeptides, acetylcholine, monoamines, purines, gases

Question 25

tiny packets that store high concentrations of neurotransmitters

Answer 25

vesicles

Question 26

where are most neurotransmitters synthesized

Answer 26

presynaptic terminal

Question 27

a neuron synthesizes chemicals it needs from what

Answer 27

substances in the diet

Question 28

chemical that breaks down neurotransmitters

Answer 28

MAO (monoamine oxidase)

Question 29

release of neurotransmitter in bursts from presynaptic terminal into synaptic cleft

Answer 29

exocytosis

Question 30

______ enters the presynaptic terminal and causes exocytosis

Answer 30

calcium

Question 31

a neurotransmitter receptor is a ______

Answer 31

protein

Question 32

_______ occur at one type of receptor. begin quickly & last for a very brief period of time

Answer 32

ionotropic effects

Question 33

______ initiates a series of metabolic reactions; slower & longer lasting

Answer 33

metabotropic effects

Question 34

properties that distinguish neuropeptides (neuromodulators) from neurotransmitters

Answer 34

need repeated stimulation; released through dendrites, cell body, or axon sides

Question 35

chemicals that are secreted by a gland or other cell & conveyed by the blood to other organs; coordinate long lasting changes

Answer 35

hormones

Question 36

glands that produce hormones

Answer 36

endocrine glands

Question 37

accumulation of neurotransmitters is broken down by ______ into inactive chemicals that cannot stimulate dopamine receptors

Answer 37

COMT

Question 38

detect the amount of neurotransmitter released & inhibit further syntheses & release after it reaches a certain level

Answer 38

autoreceptors

Question 39

special-purpose synapses that operate electrically (ex: breathing rhythmically in both lungs)

Answer 39

electrical synapses

Question 40

contact between membrane of one neuron with membrane of another

Answer 40

gap junction