Chapter 8 Study Questions (Part 1)

Question 1

what cellular structure do electrical synapses use?

Answer 1

gap junctions

Question 2

what is the advantage of an electrical synapse? (2)

Answer 2

1. really fast, simultaneously send signals
2. don’t need to run a neuron to each cell

Question 3

what is the limitation of an electrical synapse?

Answer 3

they’re just doors. signals can go both ways and that can be bad

Question 4

chemical synapses exist at 3 different sites on a neuron: what are they?

Answer 4

1. axodendritic: axon to dendrite
2. axosomatic: axon to soma
3. axoaxonic: axon to axon

Question 5

what is the relationship between synapse location and the ability for a graded potential to trigger an action potential in the postsynaptic neuron? why?

Answer 5

the impulse takes longer to arrive if it has to travel farther, and that can impact how effective it’s gonna be

Question 6

what effect does an axoaxonic synapse hve on the target cell graded potential?

Answer 6

affects how much NT that presynaptic neuron can release

Question 7

describe the directionality of chemical synapses

Answer 7

one direction

Question 8

in chemical signaling, what is passed to the target cells?

Answer 8

chemical messengers, not electrical signals

Question 9

describe the role of the action potential

Answer 9

opens voltage-gated Ca2+ channels

Question 10

describe the role of Ca+2

Answer 10

activates calmodulin

Question 11

describe the role of calmodulin

Answer 11

activates Ca-calmodulin kinase II

Question 12

describe the role of ca-calmodulin kinase II

Answer 12

targets adenylate cyclase

Question 13

describe the role of adenylate cyclase

Answer 13

makes cAMP

Question 14

describe the role of protein kinase A

Answer 14

restriction enzymes removed by cAMP

Question 15

describe the role of Rab protein

Answer 15

phosphorylated by PKA, tethering protein

Question 16

describe the role of synapsin I and II

Answer 16

tethering protein for the vesicle reserves

Question 17

a large number of vesicles containing NT fuse with the axon terminal membrane in order to release NT. what happens to all those vesicle membranes?

Answer 17

exocytosis: add to membrane

endocytosis: remove from membrane

in this case, almost all exocytosis/addition to membrane.

so, axon terminal membrane gets thick, and the cell developed a way to remove thickness to reuse it as NT transmitting

Question 18

what are gap junctions?

Answer 18

channels that permit ion transfer between neurons