Chapter 8

Question 1

What is an electrical synapse

Answer 1

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

Question 2

What is a chemical synapse

Answer 2

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

Question 3

What are the sparks

Answer 3

Electrical synapses

Question 4

What are the soups

Answer 4

Chemical synapses

Question 5

What is used for communication within a neuron

Answer 5

Action potentials

Question 6

What is communication between neurons

Answer 6

Synaptic transmission

Question 7

Who believed in electrical synapses

Answer 7

Golgi

Question 8

Who believe in chemical synapses

Answer 8

Cajal

Question 9

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

Answer 9

Otto Loewi in 1921

Question 10

How did Otto Loewi determine the existence of chemical synapses

Answer 10

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

Question 11

How many synapses are there per neuron

Answer 11

Thousands

Question 12

How many synapses are there in the brain

Answer 12

Trillions

Question 13

Where are electrical synapses more common

Answer 13

Invertebrates

Question 14

Where are chemical synapses more common

Answer 14

Mammals

Question 15

True or False:

The number of synapses per neuron varies greatly

Answer 15

True

Question 16

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

Answer 16

An action potential in the postsynaptic cell

Question 17

True or False:

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

Answer 17

True

Question 18

What is the gap junction

Answer 18

Specialized region of contact between 2 cells

Question 19

What is the gap bridged by

Answer 19

Gap junction channels

Question 20

What are gap junction channel called

Answer 20

Connexons

Question 21

What is a connexon made of

Answer 21

6 connexin

Question 22

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

Answer 22

Virtually instantaneous

Question 23

What are electrical synapses good for

Answer 23

Things that require an extremely fast response

Question 24

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

Answer 24

No they can be graded

Question 25

Are connexons full channels or hemi-channels and why

Answer 25

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

Question 26

Are connexons always open

Answer 26

No the shift to open

Question 27

What connect the 2 connexons

Answer 27

Extracellular loops

Question 28

True or False: | Electrical synapses allow for direct passage of current between cells

Answer 28

True

Question 29

What are 2 things electrical synapses are good for

Answer 29

1. Escape response | 2. Protection

Question 30

What is an example of the escape response

Answer 30

Goldfish tailwhip

Question 31

What is an example of protection

Answer 31

Aplysia ink release

Question 32

What causes the explosive release of ink in the aplysia

Answer 32

Stimulation of the tail and firing of 3 specific neurons synchronously

Question 33

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

Answer 33

Divergent communication

Question 34

Are electrical synapses present in mammals if so where

Answer 34

Yes in the brain

Question 35

Is there structural continuity to a chemical synapse

Answer 35

Nope

Question 36

What fills the void between neurons

Answer 36

Synaptic cleft

Question 37

What do chemical synapses rely on

Answer 37

Diffusion of NT

Question 38

What is a NT

Answer 38

A chemical that binds to a receptor on the postsynaptic cell

Question 39

What is the synaptic cleft

Answer 39

Space between 2 cells at the active zone

Question 40

What is an active zone

Answer 40

Dark areas or postsynaptic density

Question 41

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

Answer 41

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

Question 42

What are the 2 types of NT receptors

Answer 42

1. Ionotropic | 2. Metabotropic

Question 43

What is an ionotropic receptor

Answer 43

Ligand gated ion channel

Question 44

What is a metabotropic receptor

Answer 44

Stimulation of a second messenger

Question 45

Does a metabotropic receptor have a pore

Answer 45

Nope

Question 46

Electrical synapse vs Chemical synapse: | Distance between pre and postsynaptic cell membranes

Answer 46

Electrical: Very close Chemical: A bit farther

Question 47

Electrical synapse vs Chemical synapse: | Cytoplasmic continuity

Answer 47

Electrical: Yes Chemical: No

Question 48

Electrical synapse vs Chemical synapse: | Components

Answer 48

Electrical: Gap junction channels Chemical: Vesicles at active zones

Question 49

Electrical synapse vs Chemical synapse: | Agent of transmission

Answer 49

Electrical: Ion current Chemical: Chemical transmitter

Question 50

Electrical synapse vs Chemical synapse: | Synaptic cleft

Answer 50

Electrical: Virtually absent Chemical: Significant 1-5 mm

Question 51

Electrical synapse vs Chemical synapse: | Direction of transmission

Answer 51

Electrical: Bidirectional Chemical: Unidirectional

Question 52

What are the advantages of chemical synapses (2)

Answer 52

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

Question 53

What are the disadvantages of chemical synapses (2)

Answer 53

1. SLOW | 2. Expensive

Question 54

What are the advantages of electrical synapses (3)

Answer 54

1. FAST 2. Cheap 3. Effects are short term

Question 55

What are the disadvantages of electrical synapses (2)

Answer 55

1. Difficult to modulate | 2. Effects are short term