Synaptic Transmission

Question 1

Electrical synapses are formed by

Answer 1

Gap junctions

Question 2

Proteins which form gap junctions

Answer 2

connexins

Question 3

A connexon is formed by what

Answer 3

6 connexins which form large membrane channels

Question 4

Adjacent connexons form what

Answer 4

a continuos pore-connects the cytoplasm of two cells

Question 5

How gap junctions effect electrical potential

Answer 5

action potentials can move between cells

Question 6

Action potentials stimulate an influx of what ion? How?

Answer 6

The depolarization opens Calcium channels

Question 7

What does calcium do

Answer 7

increases vesicular fusion-thus allowing NT to be released from the cell

Question 8

How NT travels between cells

Answer 8

diffuse across the very narrow synaptic cleft

Question 9

How NT gets out of axon terminal

Answer 9

Vesicular fusion and exocytosis of NT containing vesicles

Question 10

Docking of vesicle

Answer 10

when a vesicle is held close to the membrane by proteins (standing ready to be released)

Question 11

Priming in AP

Answer 11

prepared and ready for release when the calcium comes into the synaptic cell

Question 12

v-Snare Proteins (2)

Answer 12

Synaptobrevin and synaptotagmin

in vesicles

Question 13

what binds Ca+ in vesicular fusion

Answer 13

Synaptotagmin- they then tighten up and you get full fusion (vesicle becomes part of the plasma membrane and its contents are dumped out)

Question 14

t-snares (2)

Answer 14

Syntaxin and SNAP-25

in the target

Question 15

Snare proteins are involved in what

Answer 15

vesicular fusion priming

Question 16

Axodenritic

Answer 16

Axon synapses with a dendrite

Question 17

Axospinous

Answer 17

Axon synapses to dendrite spine

Question 18

Axosomatic

Answer 18

synapses directly on the cell body (soma)

Question 19

Axoaxonic

Answer 19

Controls presynaptic modulation (release from terminal)- where axon meets the presynaptic terminal

-some inhibit some excite release of NT at synapses

Question 20

Synaptic Potential

Answer 20

Graded potentials (variable amplitude)

Question 21

Excitatory Synaptic potential

EPSP-Excitatory postsynaptic potential

Answer 21

increase the probability of firing of an AP

Question 22

inhibitory postsynaptic potential

Answer 22

Decreases the likelihood of AP by hyper-polarizing-open a Cl or K channel (K goes out and hyperpolarizes)

Question 23

Synaptic integration (neurons)

Answer 23

neurons integrate (combine) the number, Amplitude, rate of decay, and timing of EPSPs and IPSPs in deciding to fire AP

Spatial and Temporal

Question 24

Temporal Summation

Answer 24

One synapse firing slowly but if it fires more rapidly the AP can summate and get larger (if another one gets there before the first one is done the result is larger than the second alone)-ALSO longer duration

Question 25

Spatial summation

Answer 25

Two synapses separated by space collectively they cause a higher membrane potential

Question 26

Summation of EPSPs and IPSPS

Answer 26

if the IPSP and EPSP are at the same or nearly the same time the IPSP can keep the EPSP from reaching threshold and thus stop the AP

Question 27

Synaptic Plasticity and memory forming

Answer 27

strengthening or weakening of the synaptic efficacy which has been shown to last for days (9) in the lab (maybe years in vivo)

Forming a memory allows the spines to get bigger and make a synapse more effective and likely to fire

Question 28

Axons can converge on other dendrites

Answer 28

..

Question 29

Fast axonal transport

Answer 29

moves 400mm/day

vesicles move along microtubules

Question 30

Slow Axonal Transport

Answer 30

1-2mm/day involving structural proteins such as microtubules and is rate limiting for recovery of axons from damage

Question 31

Retrograde Transport

Answer 31

1/2 as fast as slow transport- from terminal to soma

Question 32

Anterograde

Answer 32

soma to axon terminal