Synapses 2

Question 1

voltage gated calcium channels

Answer 1

in active zones
open because of depolarization of terminal membrane
permeable to Ca2+
Ca2+ floods cytoplasm of axon terminal as long as calcium channels are open
resulting elevation in Ca2+ is signal that causes neurotransmitters to be released from synaptic vesicles

Question 2

exocytosis

Answer 2

how vesicles release contents
membrane of synaptic vesicle fuses to presynaptic membrane at active zone, allowing contents of vesicle to spill out into the synaptic cleft
quick

Question 3

endocytosis

Answer 3

how vesicle membrane recovered

recycled vesicle filled with neurotransmitter

Question 4

transmitter gated ion channels

Answer 4

membrane spanning proteins consisting of four or five subunits that come together to form a pore between them
when neurotransmitter binds to extracellular region sites, conformational change, pore opens, ions can pass through
not as selective for ions

Question 5

excitatory postsynaptic potential (EPSP)

Answer 5

transient postsynaptic membrane depolarization caused by presynaptic release of neurotransmitter
also caused by synaptic activation of ACh-gated and glutamate-gated ion channels

Question 6

inhibitory postsynaptic potential (IPSP)

Answer 6

transient hyper polarization of the postsynaptic membrane potential caused by the presynatpci release of the neurotransmitter
also caused by synaptic activation of glycine-gated or GABA-gated ion channels

Question 7

g protein coupled receptors

Answer 7

way for all three types of neurotransmitter to have slower, longer lasting, more diverse postsynaptic actions

Question 8

g protein transmitter action step 1

Answer 8

neurotransmitter molecules bind to receptor proteins embedded in the postsynaptic membrane

Question 9

g protein transmitter action step 2

Answer 9

receptor proteins activate small proteins (G proteins) that are free to move along the intracellular face of the postsynaptic membrane

Question 10

g protein transmitter action step 3

Answer 10

activated g proteins activate effector proteins

Question 11

second messengers

Answer 11

molecules that diffuse away in the cytosol

can activate additional enzymes in cytosol that can regulate ion channel function and alter cellular metabolism

Question 12

metabotropic receptors

Answer 12

G protein coupled receptors can trigger widespread metabolic effects so often referred to as this

Question 13

autoreceptors

Answer 13

presynaptic receptors that are sensitive to the neurotransmitter released by the presynaptic terminal
usually g protein coupled receptors that stimulate second messenger formation
function as safety valves to reduce release when concentration of neurotransmitter in synaptic cleft gets too high

Question 14

desensitization

Answer 14

uninterrupted exposure to high concentrations of ACh at neuromuscular junction leads to this
transmitter-gated channels close

Question 15

steps of synaptic transmission

Answer 15

neurotransmitter synthesis, loading into synaptic vesicles, exocytosis, binding and activation of receptors, reuptake, degradation

Question 16

neuropharmacology

Answer 16

study of the effects of drugs on nervous system tissue

Question 17

black widow

Answer 17

affects transmitter release
increases then eliminates ACh release at neuromuscular junction
venom binds with proteins on outside of presynaptic membrane, forming pore that depolarizes terminal and allows Ca2+ to enter and deplete transmitter

Question 18

clostridium botulinum

Answer 18

produce toxins that attack chemical synaptic transmission

destroy certain SNARE proteins in presynaptic terminals which are critical for transmitter release

Question 19

cobra

Answer 19

bungarotoxin, peptide, binds tightly to postsynaptic nicotinic ACh receptors
prevents activation of nicotinic receptors by ACh, paralyzes respiratory muscles of victims

Question 20

organophosphates

Answer 20

irreversible inhibitors of ACh

kill victim by causing desensitization of ACh receptors

Question 21

inhibitors

Answer 21

inhibit normal function of specific proteins involved in synaptic transmission

Question 22

receptor antagonists

Answer 22

inhibitors of neurotransmitter receptors

bind to receptors and block (antagonize) normal action of transmitters

Question 23

curare

Answer 23

arrow tip poison to paralyze prey
binds to ACh receptors on skeletal muscle cells and blocks actions of ACh
prevents muscle contraction

Question 24

receptor agonists

Answer 24

drugs mimic actions of naturally occurring neurotransmitters

Question 25

nicotine

Answer 25

binds to and activates ACh receptors in skeletal msucle

Question 26

nicotinic ACh receptors

Answer 26

Each gated ion channels in muscle