Neurotransmission

Question 1

What is contained is presynaptic part?

Answer 1

Vesicles containing neurotransmitter

Question 2

Describe the structure of post-synaptic?

Answer 2

Junctional folds with Ach receptors and cholinesterase enzymes

Question 3

Where is the origin of end plate potentials?

Answer 3

At the endplate

Question 4

What do mini end plate potentials do?

Answer 4

Spontaneous release of one packet of neurotransmitter into the synaptic cleft

Question 5

What is meant by a quantal?

Answer 5

Neurotransmitter put into packets

Question 6

What are EPPs built from?

Answer 6

A large quantity of minEPPs

Question 7

What neurotransmitter produces an EPSP?

Answer 7

Acetylcholine

Question 8

What receptor does Ach fuse to?

Answer 8

Nicotinic Ach receptor

Question 9

How many molecules of Ach are required to activate receptor?

Answer 9

2

Question 10

How does the nicotinic Ach receptor change when the Ach fuses with it?

Answer 10

Rearrangment of receptor allows permeation of ions through aqueous pore. Permeable to both Na+ and K+ when opened, depolarising membrane

Question 11

What receptor type is involved in generating IPSP?

Answer 11

Ligand gated chlorine channel

Question 12

What neurotransmitter is involved in generating IPSPs in the brain?

Answer 12

GABA

Question 13

What neurotransmitter is involved in generating IPSPs in the spinal cord?

Answer 13

Glycine

Question 14

What two changes occur in GABA receptors in the generation of IPSPs?

Answer 14

• Hyperpolarisation of membrane

- Membrane becomes leakier to current so more difficult to generate a current

Question 15

What stimulus are muscle spindle fibres sensitive to?

Answer 15

Stretch (mechanoreceptor)

Question 16

Describe how monosynaptic reflex works?

Answer 16

• Muscle spindle fibres sends la afferent into spinal cord via dorsal root
• Synapses in ventral horn to alpha motor neuuron
• Sends axons to homonymous muscle making synapses with numerous muscle fibres

Question 17

What is meant by recipricol antagonistic inhibition?

Answer 17

When one muscle is flexed, other is inhibited so it can relax

Question 18

How is the antagonistic muscle relaxed?

Answer 18

Also well as monosynaptic activation of flexor neuron, there is another synapse onto interneuron in spinal cord.
Synapse is excitatory on inhibitory interneuron which release glycine at its synapse to inhibit antagonistic muscle.

Question 19

What is the difference between neurotransmission, neuromodulation and neurotrophic factors?

Answer 19

Neurotransmission: ms
Neuromodulation: takes seconds to minutes
Neurotrophic factors: slowest of all- minutes to hours

Question 20

What type of receptor is used in fast neurotransmission

Answer 20

Pentameric and tetrameric receptors that incorporate ion channels

Question 21

What type of receptor is used in neuromodulation?

Answer 21

G protein coupled receptor

Question 22

What happens when neuromodulator binds to GPCR?

Answer 22

Activates second messenger which causes series of reaction which causes modulation of ion channels

Question 23

Is glutamate fast, modulator or both?

Answer 23

Both

Question 24

Is Ach fast, modulator or both?

Answer 24

Both

Question 25

Is glutamate fast, modulator or both?

Answer 25

Both

Question 26

Is GABA fast, modulator or both?

Answer 26

Both

Question 27

Is glycine fast, modulator or both

Answer 27

Fast

Question 28

Is 5-HT fast, modulator or both?

Answer 28

Both

Question 29

Is noradrenaline fast, modulator or both?

Answer 29

Modulator

Question 30

Is dopamine fast, modulator or both?

Answer 30

Modulator

Question 31

Where specifically does Ach bind to on channels?

Answer 31

C loops

Question 32

Name the 2 mechanisms involved in termination of transmitter?

Answer 32

Neurotransmitter breakdown | Neurotranmitter reuptake

Question 33

What enzyme breaks down Ach?

Answer 33

Acetylcholinesterase

Question 34

What can inhibit acetylcholinesterase?

Answer 34

Organophosphate nerve agents

Question 35

How is glutamate reuptaken?

Answer 35

Glutamate transporter reuptakes into neurons and glial cells | Runs of Na+ gradient

Question 36

How is GABA reuptaken?

Answer 36

reuptaken into presynaptic terminals and astrocytes by GATs

Question 37

What is M response?

Answer 37

direct activation of motor unit by electrical stimulation

Question 38

What is H reflex?

Answer 38

Electrical equivelent to stretch reflex

Question 39

What is F wave?

Answer 39

Antidromic motor nerve action potentials bouncing off the alpha motor neurons

Question 40

What is the effect of peripheral demyelination?

Answer 40

Effects conduction time or number of axons that work

Question 41

What is meant by giant motor unit and what condition is it seen in?

Answer 41

Alpha motor neurons die- denervation of motor fibres. surviving motor neurons sprout and send new collaterals to muscle fibres. Large motor units when 1 motor neuron innervates more than usual ALS