Synaptic Transmission

Question 1

Define synapse?

Answer 1

Junction between 2 neurons

Question 2

State 2 diff types synapses?

Answer 2

Electrical
Chemical

Question 3

What is excitatory synapse?

Answer 3

Membrane potential of postsynaptic neuron depolarised

Question 4

What is inhibitory synapse?

Answer 4

Membrane potential of postsynaptic neuron hyperpolarised or stabilised at resting potential

Question 5

What 5 processes synaptic transmission?

Answer 5

1) Manufacture
2) Storage- vesicles
3) Release- action potential
4) Interaction with post-synaptic receptors
5) Inactivation- breakdown or reuptake

Question 6

Does all or some neurotransmitter bind?

Answer 6

Small fraction

Question 7

What occurs when neurotransmitters bind?
Excitatory
Inhibitory

Answer 7

Depolarisation or hyperpolarisation (depending on channel type)
Depolarisation- excitatory channels (EPSPs)
Hyperpolarisation- inhibitory channels (IPSPs

Question 8

What are 2 types of summation?

Answer 8

Temporal summation- input signals arrive from same
presynaptic cells at different times
Spatial summation- simultaneous stimulation by several presynaptic neurons

Question 9

How are neurotransmitters inactivated/removed from synaptic cleft? (3)

Answer 9

1) Actively transported back to presynaptic axon terminal-
reuptake
2) Diffuse away from receptor site
3)Enzymatically transformed into inactive substances

Question 10

What is most common synapse? Chemical or electrical?

Answer 10

Chemical

Question 11

In chemical synapse what joins plasma membranes of pre and post synaptic cells?

Answer 11

Synaptic cleft

Question 12

What holds synaptic vesicle and neurotransmitter?

Answer 12

Axon ends in axon terminal

Question 13

Label

Answer 13

Question 14

In chemical synapses what prevents direct propogation of current?

Answer 14

Synaptic cleft

Question 15

Flow of chemical synapse

Answer 15

Question 16

What cell is essential for reuptake of neurotransmitters?

Answer 16

Astrocyte

Question 17

Function of astrocyte?

Answer 17

Eseential reuptake of neurotransmitters

Question 18

What joins plasma membranes of pre and postsynaptic cells in electrical synapse?

Answer 18

Gap junctions

Question 19

What is faster electrical or chemical synapases?

Answer 19

Electrical

Question 20

Where is electrical synapses found?

Answer 20

Brainstem neurones
Hypothalamus
Hormone secretion

Question 21

State process neurotransmitter release?

Answer 21

1) AP reaches presynaptic terminal
2) Voltage gated calcium channels open
3) Vesicles move to release sites- fuse with pre-synaptic membrane (exocytosis)
4) Neurotransmitter diffuses across synaptic cleft
5) Neurotransmitter attaches to receptor site on post-synaptic neuron
6) Receptor transmits signal
7) Neurotransmitter inactivated

Question 22

Answer 22

Question 23

What are 2 types of post synaptic receptors?

Answer 23

Ionotropic receptor
Metabotropic receptors

Question 24

Ionotropic receptor
State:
Type
Response
Speed response
Length response

Answer 24

Type- Ligand gated ion channels
Response- Allow ion flux- change cell voltage
Speed response- Rapid
Length response- Short acting

Question 25

Metabotropic receptor
State:
Type
Response
Speed response
Length response

Answer 25

State:
Type- G protein coupled receptor
Response- Act through secondary messenger
- Cause cellular effect
Speed response- Slow
Length response- Prolonged

Question 26

What type of receptors have ligand gated ion channels?

Answer 26

Ionotropic receptors

Question 27

What type of receptors have G Protein coupled receptors?

Answer 27

Metabotropic receptors

Question 28

What receptors change cell voltage?

Answer 28

Ionotropic receptors

Question 29

What receptors act as secondary messengers?

Answer 29

Metabotropic receptors

Question 30

What receptors cause rapid response?

Answer 30

Ionotropic receptors

Question 31

What receptors cause slow response?

Answer 31

Metabotropic receptors

Question 32

What receptors causes rapid response?

Answer 32

Ionotropic receptor