Phys 1 synaptic transmission

Question 1

Types of synaptic transmission?

Answer 1

Electrical

Chemical

Question 2

Electrical synaptic transmission

vs

Chemical Synaptic transmission

Answer 2

E.

• Fast
• Gap junctions
• multidirectional
• (think synaptic cleft are connected)
• ex. Heart

C.

• Slower
• synaptic gap (normal synaptic cleft)
• unidirectional
• ex. ANS

Question 3

What are the sequence of events in a chemical synapse?

Answer 3

1. Neurons synthesize NTs
2. NTs stored in axon terminal
3. Action potential triggers release of NTs
   
   1. this usually happens by AP causes Ca channel to open which causes NTs to fuse and leave
4. NT travel to bind receptors
5. Post synaptic response= change in membrane pot
6. NTs: reuptake, diffuse away, break down

Question 4

Criteria for NTs?

Answer 4

1. synthesis in pre-Synaptic neuron
   
   1. Food substrates (aa)
   2. soma of neurons
2. Released in response to pre-synaptic AP
   
   1. Ca dependent
   2. Quantal Hypothesis
   3. NT release= [increse Ca]+[increse in AP]
3. post synaptic receptors receive/respond to signal
4. NTs must somehow be inactivated
   
   1. drugs can alter this

Question 5

what is the quantal hypothesis

Answer 5

each time synaptic vesicle released 5000 to 10000 molecules of NT released

More NTs needed more AP needed

Question 6

Neurotransmitter classes

Answer 6

Choline esters

Biogenic Amines

AA

Neuropeptides

Question 7

Choline esters

Answer 7

acetylcholine

• muscarinic mAChR
• Nicotinic nAChR

Question 8

Biogenic Amines

Answer 8

DA, EP, NE, 5-HT (serotonin)

Question 9

AAs

Answer 9

glutamate, glycine, GABA

Question 10

Neuropeptides

Answer 10

ACTH, Glucagon, Endorphins

Question 11

Postsynaptic response can have what outcomes?

Answer 11

AP

EPSP- Excitatory postsynaptic potential

• Closer to threshold

IPSP- inhibitory postsynaptic potential

• further from theshold

Question 12

EPSP

Answer 12

excitatory

• K out of cell
• Na into cell
• Net positive change
• get closer to threshold

Question 13

IPSP

Answer 13

further from threshold

• K out of cell

Or

• • charge into cell (Cl-)

Question 14

Summation (Not specific types)

Answer 14

Balancing act EPSP+IPSP

keep eachother in check will be movement from resting membrane potential but not as large as either by itself

Question 15

Summation types

Answer 15

Spatial

Temporal

Question 16

Spatial

Answer 16

EPSP only

• many pre-synaptic neurons
• signal at the same time
• causes a large jump in one step

Question 17

Temporal

Answer 17

EPSP only

• One pre-synaptic neuron
• Pre-synaptic signal happens over time
• The one nerve will fire multiple times until it reaches the threshold then it will depolarize

Question 18

Types of acetylcholine receptors

Answer 18

Nicotinic

Muscarinic

Question 19

Nicotinic receptors

Answer 19

ionotropic

• ACh bind nAChR
• increase in Na and K perm
• Membrane depolarization
• AP excitation

skeletal muscle

Question 20

Muscarinic receptors

Answer 20

Metabotropic

• G-protein coupled receptor GPCR
• ACh bind nAChR
• release alpha subunit which is bound to GTP
• Beta and gamma go and elicit responses

Autonomic NS

Parasympathetic