Synaptic Transmission

Question 1

What are the two general ways in which cells communicate?

Answer 1

Electrical and Chemical Synapse

Question 2

What is an electrical synapse?

Answer 2

Gap junctions that transfer ions from the cytoplasm of one cell to another

Question 3

What is a chemical synapse?

Answer 3

The release of a chemical that diffuses to, and acts upon, another cell

Question 4

Most significant electrical synapses in the human body?

Answer 4

Heart, Liver, Lens, and Myelin Sheath

Question 5

Cell membranes are normally separated by _____. Gap junctions have cells separated by ____ __.

Answer 5

20nm

3.5 nm

Question 6

Another name for a gap junction?

Answer 6

Connexon

Question 7

What is a gap junction made of?

Answer 7

6 Connexins

Question 8

The presynaptic cell must be lined up with

Answer 8

the postsynaptic connexon

Question 9

What determines what can pass through a gap junction?

Answer 9

Pore Size

Question 10

What conditions may cause gap-channels to close?

Answer 10

Lowered cytoplasmic pH or elevated Ca2+

Question 11

For two non-coupled adjacent cells, depolarization will cause what in the other?

Answer 11

nothing

Question 12

For two coupled adjacent cells, depolarization will cause what in the other?

Answer 12

Depolarization

Question 13

Why might the hypothalamus require gap junctions? Cardiac muscle?

Answer 13

To ensure coordinated release/contraction amongst many cells

Question 14

Relationship btw CMT and gap junctions?

Answer 14

Cells wrap around, connect layers with gap junctions to allow the deepest layers to get sustenance.

Question 15

What is the major mechanism for the release of neurotransmitters?

Answer 15

Vesicular Secretion

Question 16

Depolarization of the terminal membrane of axons causes what?

Answer 16

Opening of voltage gated Ca channels

Question 17

Two proteins involved in priming synaptic vesicles for fusion.

Answer 17

NSF and SNAPs

Question 18

What do NSF and SNAPs regulate?

Answer 18

Assembly of the SNARE complex

Question 19

Name three SNARE proteins.

Answer 19

Synaptobrevin, syntaxin, and SNAP-25

Question 20

SNARE protein responsible for Ca regulation?

Answer 20

Synaptotagmin

Question 21

What does synaptotagmin do?

Answer 21

When Ca conc. is elevated, inserts into cell membrane, leading to fusion of membranes and release of contents

Question 22

What are end plates?

Answer 22

Specialized sites where the presynaptic axon terminates on a muscle fiber

Question 23

What is an end plate potential?

Answer 23

An AP in the presyn… neuron elicits a transient depolarization of the muscle fiber.

Question 24

Very low Ca concentration will do what to EPPs?

Answer 24

Make them much smaller, but same shape

Question 25

What are the much smaller waves (but same shape/pharm response) called?

Answer 25

Miniature End Plate Potentials

Question 26

Increasing external Ca will do what to amplitude?

Answer 26

Nothing.

Question 27

What does increasing external Ca do for muscle cells?

Answer 27

Decrease the number of failures, higher release probability

Question 28

What is a quantum?

Answer 28

The amount of NT in a vesicle

Question 29

How many molecules of AcCho are required to set off a MEPP

Answer 29

7000

Question 30

Enzyme that inactivates acetylcholine? Products of this reaction??

Answer 30

Acetylcholinesterase | Choline and Acetyl CoA

Question 31

Enzyme that reassembles acetylcholine?

Answer 31

acetyltransferase

Question 32

After initial release, what two parts are recycled?

Answer 32

Cell membrane and choline

Question 33

What is spatial integration?

Answer 33

Integration of multiple signals from different locations on a dendrite arriving at once

Question 34

A larger lambda means....

Answer 34

less decay over length, greater chance for synaptic potentials to summate

Question 35

What is temporal integration?

Answer 35

Integration of multiple inputs from the same axon occurring at different times.

Question 36

A larger tau means...

Answer 36

less decay over time, greater chance of summation.

Question 37

Define EPSP

Answer 37

Excitatory Post Synaptic Potential | Excitatory NT increase Na permeability

Question 38

Review 4-11

Answer 38

That seemed important

Question 39

Why are EPSPs tricky to navigate?

Answer 39

Because an EPSP changes the permeability of both Na and K, depending on the membrane voltage.

Question 40

What equation can be used to determine which way EPSP values will go?

Answer 40

Em - Eion = X | Move toward Eion of the larger X

Question 41

What are IPSPs? What do they do?

Answer 41

Inhibitory Post Synaptic Potential Increase Cl- permeability at the postsynaptic membrane Causes hyperpolatization, fewer APs

Question 42

Aside from Cl-, what can cause hyperpolarization to occur?

Answer 42

Increased K permeability at the postsynaptic

Question 43

How does level of depolarization influence IPSPs?

Answer 43

More depolarized cell will require a greater IPSP

Question 44

Can IPSPs and EPSPs interact?

Answer 44

Yes

Question 45

How does the brain code information?

Answer 45

Place codes Intensity Coding Recruitment Input Organization

Question 46

How does recruitment promote mapping?

Answer 46

Axons have a limited range. Increased axons will increase the dynamic range.

Question 47

How does the CNS accomplis input organization?

Answer 47

Center surround fields maximize contrast

Question 48

How do you treat myasthenia gravis?

Answer 48

Acetylcholinesterase Inhibitor