Chapter 8 Flashcards

1
Q

What is an electrical synapse

A

When the pre and postsynpatic cells are touching allowing electrical signals to pass across

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2
Q

What is a chemical synapse

A

When there is a space between 2 neurons and chemicals are released into the synaptic cleft effecting the postsynaptic neuron

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3
Q

What are the sparks

A

Electrical synapses

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4
Q

What are the soups

A

Chemical synapses

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5
Q

What is used for communication within a neuron

A

Action potentials

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6
Q

What is communication between neurons

A

Synaptic transmission

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7
Q

Who believed in electrical synapses

A

Golgi

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8
Q

Who believe in chemical synapses

A

Cajal

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9
Q

Who devised the first definitive experiment to prove the existence of chemical synapses

A

Otto Loewi in 1921

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10
Q

How did Otto Loewi determine the existence of chemical synapses

A

Put 2 frog hearts in separate beakers connected by a tube, one hearts vagus nerve was stimulated causing the heart to contract slower, and eventually the other heart start to contract slower

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11
Q

How many synapses are there per neuron

A

Thousands

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12
Q

How many synapses are there in the brain

A

Trillions

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13
Q

Where are electrical synapses more common

A

Invertebrates

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14
Q

Where are chemical synapses more common

A

Mammals

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15
Q

True or False:

The number of synapses per neuron varies greatly

A

True

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16
Q

At an electrical synapse what does activation of the presynaptic cell result in

A

An action potential in the postsynaptic cell

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17
Q

True or False:

Synaptic transmission at an electrical synapse depolarize the postsynaptic cell above threshold

A

True

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18
Q

What is the gap junction

A

Specialized region of contact between 2 cells

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19
Q

What is the gap bridged by

A

Gap junction channels

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20
Q

What are gap junction channel called

A

Connexons

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21
Q

What is a connexon made of

A

6 connexin

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22
Q

Is the stimulation of the postsynaptic cell delayed or virtually instantaneous in an electrical synapse

A

Virtually instantaneous

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23
Q

What are electrical synapses good for

A

Things that require an extremely fast response

24
Q

Does an electrical synapse need to reach threshold for a response in the postsynaptic cell

A

No they can be graded

25
Q

Are connexons full channels or hemi-channels and why

A

Hemi-channels because you need 2 connexons to make a full channel

26
Q

Are connexons always open

A

No the shift to open

27
Q

What connect the 2 connexons

A

Extracellular loops

28
Q

True or False:

Electrical synapses allow for direct passage of current between cells

A

True

29
Q

What are 2 things electrical synapses are good for

A
  1. Escape response

2. Protection

30
Q

What is an example of the escape response

A

Goldfish tailwhip

31
Q

What is an example of protection

A

Aplysia ink release

32
Q

What causes the explosive release of ink in the aplysia

A

Stimulation of the tail and firing of 3 specific neurons synchronously

33
Q

What is the stimulation of the aplysia tail activating 3 neurons an example of

A

Divergent communication

34
Q

Are electrical synapses present in mammals if so where

A

Yes in the brain

35
Q

Is there structural continuity to a chemical synapse

A

Nope

36
Q

What fills the void between neurons

A

Synaptic cleft

37
Q

What do chemical synapses rely on

A

Diffusion of NT

38
Q

What is a NT

A

A chemical that binds to a receptor on the postsynaptic cell

39
Q

What is the synaptic cleft

A

Space between 2 cells at the active zone

40
Q

What is an active zone

A

Dark areas or postsynaptic density

41
Q

What are the steps of activity in a chemical synapse (6)

A
  1. Action potential arrives
  2. Ca2+ enters
  3. Vesicles fuse with presynaptic membrane
  4. NT is released through exocytosis
  5. NT diffuses across synaptic cleft
  6. NT binds to receptors on the postsynaptic cell membrane changing the postsynaptic membrane potential
42
Q

What are the 2 types of NT receptors

A
  1. Ionotropic

2. Metabotropic

43
Q

What is an ionotropic receptor

A

Ligand gated ion channel

44
Q

What is a metabotropic receptor

A

Stimulation of a second messenger

45
Q

Does a metabotropic receptor have a pore

A

Nope

46
Q

Electrical synapse vs Chemical synapse:

Distance between pre and postsynaptic cell membranes

A

Electrical: Very close
Chemical: A bit farther

47
Q

Electrical synapse vs Chemical synapse:

Cytoplasmic continuity

A

Electrical: Yes
Chemical: No

48
Q

Electrical synapse vs Chemical synapse:

Components

A

Electrical: Gap junction channels
Chemical: Vesicles at active zones

49
Q

Electrical synapse vs Chemical synapse:

Agent of transmission

A

Electrical: Ion current
Chemical: Chemical transmitter

50
Q

Electrical synapse vs Chemical synapse:

Synaptic cleft

A

Electrical: Virtually absent
Chemical: Significant 1-5 mm

51
Q

Electrical synapse vs Chemical synapse:

Direction of transmission

A

Electrical: Bidirectional
Chemical: Unidirectional

52
Q

What are the advantages of chemical synapses (2)

A
  1. Each NT can have different effects on the postsynaptic cell
  2. Allow complex modulation
53
Q

What are the disadvantages of chemical synapses (2)

A
  1. SLOW

2. Expensive

54
Q

What are the advantages of electrical synapses (3)

A
  1. FAST
  2. Cheap
  3. Effects are short term
55
Q

What are the disadvantages of electrical synapses (2)

A
  1. Difficult to modulate

2. Effects are short term