synaptic plasticity

Question 1

short term plasticity

Answer 1

< 30 min

Question 2

long term plasticity

Answer 2

days, weeks, months

Question 3

synaptic facilitation

Answer 3

multiple APs in rapid succession strengthens the synapse by increasing presynaptic calcium availability

Question 4

synaptic depression

Answer 4

depletion of synaptic vesicles leads to decreased neurotransmitter release thus weakened synapse communication

Question 5

synaptic augmentation and potentiation

Answer 5

increase Ca in presynaptic neuron, which increased binding of synaptic vesicles with the membrane of the axon terminal

Question 6

augmentation

Answer 6

short acting, decays in a few seconds

Question 7

potentiation

Answer 7

lasts several seconds to minutes

Question 8

long term potentiation (LTP)

Answer 8

long lasting increase in synaptic strength

Question 9

long term depression (LTD)

Answer 9

long lasting decrease in synaptic strength

Question 10

AMPA receptors

Answer 10

• ligand gated (glutamate)
• Na enters the cell (depolarization)

Question 11

NMDA receptors

Answer 11

• ligand gated (glutamate)
• also VG Mg
• Ca and Na enter the cell (depolarization)

Question 12

habituation

Answer 12

decreased responsiveness to repeated applications of a stimulus
- decreased glutamatergic synaptic transmission

Question 13

sensitization

Answer 13

heightened response to non-noxious stimuli as a result of previous exposure to a noxious stimulus
- increased activity of neuromodulating interneurons
- increased serotonin at presynaptic terminals of sensory neurons

Question 14

chemical injury

Answer 14

ions, neurotransmitters

Question 15

hypoxia

Answer 15

lack of oxygen

Question 16

infection

Answer 16

microbe comes in

Question 17

mechanical injury

Answer 17

laceration or cut, traction or stretch on the nervous tissue

Question 18

neuropraxia

Answer 18

signal transmission is briefly interrupted; no neural death/axonal damage
- completely reversible
- ex: foot falling asleep

Question 19

axonotmesis

Answer 19

damage to axon only –> happens in PNS, axon can regenerate

Question 20

neurotmesis

Answer 20

damage to both the axon and CT around it
- worst case scenario

Question 21

grade 1

Answer 21

neuropraxia

Question 22

grade 2

Answer 22

intact endoneurium; axon damage

Question 23

grade 3

Answer 23

intact perineurium, axon and endoneurium damaged

Question 24

grade 4

Answer 24

intact epineurium; axon, endoneurium, perineurium damaged

Question 25

grade 5

Answer 25

neurtomesis

Question 26

grade 6

Answer 26

multifocal mixed injury
- most common form of injury

Question 27

anterograde/wallerian degeneration

Answer 27

• within minutes: neurofilaments swell and fragment
• replication of mitochondria
• myelin retracts from the axon
• within 12 hours: myelin is swollen and irregular
• within 2-3 days: myelin becomes ellipsoid

Question 28

proximal / retrograde degeneration

Answer 28

• in opposite direction (toward the cell body)
• only 1-2 nodes of Ranvier backward

Question 29

way to recover from injury

Answer 29

1. regneration
2. reinstatement of blood flow
3. recovery of synaptic effectiveness

Question 30

neural regneration

Answer 30

• ONLY IN PNS
• axons can sprout within 6 hours post injury
• growth spurts find endometrial tubes

Question 31

factors that interfere with regeneration

Answer 31

• distance
• scarring
• location of injury on the axon
• wrong endometrial tubes

Question 32

sprouting of collaterals

Answer 32

• major mechanism of recovery in CNS
• intact neurons send out new projections to synapse on orphaned postsynaptic cells

Question 33

denervation hypersensitivity

Answer 33

increase receptors on the postsynaptic neurons

Question 34

synaptic hyper effectiveness

Answer 34

increase NT from the neighboring healthy neurons