Quiz 6

Question 1

Electrical synapse

Answer 1

result of gap junctions
bi-directional signaling
direct electron coupling
second cell mirrors the first cell

Question 2

chemical synapse

Answer 2

synaptic cleft= gap between neurons
anterograde
signals pre- to post-synaptic
axon terminal has mitochondria, ER, and vesicles
vesicles loaded with NT bind to mem and release NT into synaptic cleft

Question 3

Events at Chemical Synapse: 1

Answer 3

axon potential depolarizes axon terminal

Question 4

Events at Chemical Synapse: 2

Answer 4

depolarization opens voltage-gated Ca channels; Ca flows into cell

Question 5

Events at Chemical Synapse: 3

Answer 5

Ca entry triggers exocytosis of vesicle contents

Question 6

Events at Chemical Synapse: 4

Answer 6

NT diffuses across synaptic cleft and binds to receptors on post-synaptic cell

Question 7

Events at Chemical Synapse: 5

Answer 7

NT binding initiates a response in post-synaptic cell
- rapid short-acting fast synaptic potential
- slow synaptic potentials

Question 8

Vesicle Cycle

Answer 8

1. exocytosis
2. endocytosis

Question 9

Exocytosis steps

Answer 9

1. filling of NT
2. vesicle translocation
3. docking
4. priming
5. fusion with membrane

Question 10

Endocytosis steps

Answer 10

1. membrane translocation
2. coating with clathrin
3. fission of coated vesicle from membrane
4. uncoating from clathrin
5. recycling (by several paths)

Question 11

Two types of Post-synaptic responses

Answer 11

rapid short-acting fast synaptic potentials
slow synaptic potentials

Question 12

rapid short-acting fast synaptic potentials

Answer 12

neurocrine signal opens ligand-gated ion channels
- more Na in- EPSP (excitatory depolarization)
- more K out/Cl in- IPSP (inhibitory hyperpolarization

Question 13

slow synaptic potentials

Answer 13

neurocrine signal reaches G protein coupled receptor
this activates second messenger pathway
- may open/close ion channels
- may modify existing proteins or regulate synthesis of new proteins

Question 14

may open/ close ion channels causes…

Answer 14

open
- more Na in (EPSP)
- more K out/Cl in (IPSP)
close
- less Na in (IPSP)
less K out/Cl in (EPSP)

Question 15

may modify existing proteins or regulate synthesis of new proteins causes…

Answer 15

coordinated intracellular response

Question 16

NMJ: Pre-synaptic components

Answer 16

synaptic knob
synaptic vesicle

Question 17

NMJ: Post-synaptic components

Answer 17

motor end plate
Ach receptors
Acetylcholinesterase

Question 18

synaptic knob

Answer 18

expanded end of neuron

Question 19

synaptic vesicles

Answer 19

membrane-bound sacs filled with ACh

Question 20

synaptic cleft

Answer 20

narrow space separating synaptic cleft from motor end plate

Question 21

motor end plate

Answer 21

region of sarcolema (plasma membrane) across from synaptic knob (with folds and indentations to increase surface area)

Question 22

ACh receptors

Answer 22

in motor end plate; bind to ACh

Question 23

Acetylcholinesterase (AChE)

Answer 23

enzyme in synaptic cleft that breaks down ACh

Question 24

NMJ Step 1

Answer 24

neuron action potential invades terminal

Question 25

NMJ Step 2

Answer 25

Ca enters voltage gated ion channels

Question 26

NMJ Step 3

Answer 26

ACh release

Question 27

NMJ Step 4

Answer 27

ACh binding opens ion channels

Question 28

NMJ Step 5

Answer 28

Na entry

Question 29

NMJ Step 6

Answer 29

local current between depolarized end plate and adjacent muscle plasma membrane

Question 30

NMJ Step 7

Answer 30

muscle fiber action potential initiation

Question 31

NMJ Step 8

Answer 31

propagated action potential in muscle plasma membrane

Question 32

NMJ Step 9

Answer 32

ACh degradation

Question 33

Skeletal muscle is made up of

Answer 33

connective tissue
nerves and blood vessels
muscle fascicle: made up of muscle fibers

Question 34

motor unit

Answer 34

a single motor neuron and the muscle fibers it controls