Neuromuscular Junction

Question 1

What is synaptic transmission?

Answer 1

postsynaptic signaling interpreting the transmitted signal into a change in postsynaptic Vm

Question 2

What are the 2 types of connections within synaptic transmission?

Answer 2

axiosymatic and axiodendritic

Question 3

What are the classes of mmebrane receptors?

Answer 3

ionotropic (ligand gated) and metabotropic (GPCR)

Question 4

What type of response is ionotropic?

Answer 4

fast

Question 5

What type of response is metabotropic?

Answer 5

slower and variable

Question 6

What are the 5 ionotropic receptors?

Answer 6

1. Ach
2. glutamate
3. 5-HT3
4. GABA
5. glycine

Question 7

What is the Ach receptor?

Answer 7

• receptor at neuromuscular junction
• plays role in learning and memory
• curare

Question 8

What is the glutamate receptor?

Answer 8

• NMDA, AMPA receptors
• letamine

Question 9

What is the 5-TH3 receptor?

Answer 9

• all antagonists are antiemetic
• serotonin receptor channel

Question 10

What is the GABA receptor?

Answer 10

• types A and C
• causes membrane potential hyperpolarization through Cl-
• benzodiazepines, kava, valerian

Question 11

What is the glycine receptor?

Answer 11

• glycine and taurine (agonist)
• strychnine (antagonist, rat poison)

Question 12

What are the 4 types of metabotropic receptors?

Answer 12

1. Ach
2. metabotropic glutamate
3. biogenic amines
4. GABA

Question 13

Metabotropic receptors have what type of coupled receptors?

Answer 13

G protein

Question 14

What type of GABA receptor is in metabotropic receptors?

Answer 14

• type B
• agonists: ethanol and baclofen

Question 15

How many transmembrane segments does the receptor structure have?

Answer 15

7

Question 16

What occurs when the G protein is activated after metabotropic receptor activation?

Answer 16

• directly activates/deactivates channel
• activation of effector molecule; synthesis/activation of 2nd messenger

Question 17

What occurs when there is an activation of effector molecule synthesis/activation of 2nd messenger after metabotropic receptor activation?

Answer 17

• increases/decreases kinase activity
• directly activates/deactivates channel

Question 18

What occurs when there is an increase/decrease in kinase activity after metabotropic receptor activation?

Answer 18

• leads to phosphorylation/dephosphorylation of ion channels causing change in channel activity
• cause increase/decrease in channel subunit/protein production

Question 19

What are the sources of Ca+?

Answer 19

• plasma membrane: voltage gated Ca+ channels, various ligand channels
• endoplasmic reticulum: IP3 receptors, ryanodine receptors

Question 20

What are the removal mechanisms of Ca+?

Answer 20

• plasma membrane: Na+/Ca+ exchanger, Ca+ pump
• ER: Ca+ pump
• mitochondria

Question 21

What are the sources for cAMP?

Answer 21

adenylyl cyclase

Question 22

What is the intracellular target for cAMP?

Answer 22

protein kinase A

Question 23

What is the source for IP3?

Answer 23

phospholipase C

Question 24

What is the intracellular target for IP3?

Answer 24

IP3 receptors on ER

Question 25

What is the source for diacylglycerol?

Answer 25

phospholipase C

Question 26

What is the intracellular target for diacylglycerol?

Answer 26

protein kinase C

Question 27

What are the second messengers?

Answer 27

1. Ca+ 2. cAMP 3. IP3 4. diacylglycerol

Question 28

What is the G-protein, cascade, and target action for norepinephrine?

Answer 28

* G-protein: Gs * cascade: adenylyl cyclase -> cAMP -> protein kinase A * target: increase protein phosphorylation

Question 29

What is the G-protein, cascade, and target action for glutamate?

Answer 29

* G-protein: Gq * cascade: phospholipase C -> diacylglycerol -> protein kinase, IP3 -> Ca+ release * target: increase protein phosphorylation and activate Ca binding proteins

Question 30

What is the G-protein, cascade, and target action for dopamine?

Answer 30

* G-protein: Gi * cascade: adenylyl cyclase -> cAMP -> protein kinase A * target: decrease protein phosphorylation

Question 31

What are EPSPs?

Answer 31

postsynaptic potentials that increase probability of causing the postsynaptic cell to fire an AP

Question 32

What are IPSPs?

Answer 32

postsynaptic potentials that decrease probability of causing the postsynaptic cell to fire an AP

Question 33

What is the relationship between EPSPs and the threshold?

Answer 33

reverse potential of induced conductance is more positive than threshold

Question 34

What is the relationship between IPSPs and the threshold?

Answer 34

reverse potential of induced conductance is more negative than threshold

Question 35

What is the affect of major excitatory neurotransmitters on postsynaptic membrane?

Answer 35

depolarization caused by activation of cationic channels (Na+ and Ca+)

Question 36

What is the affect of major inhibitory neurotransmitters on postsynaptic membrane?

Answer 36

hyperpolarization caused by activation of chloride channels

Question 37

What are examples of excitatory neurotransmitters?

Answer 37

1. Ach 2. glutamate 3. serotonin 4. histamine 5. catecholamines

Question 38

What are examples of inhibitory neurotransmitters?

Answer 38

GABA and glycine

Question 39

What is convergence?

Answer 39

several neurons synapse onto a single neuron (input)

Question 40

What is divergence?

Answer 40

single neuron projects onto several neurons (output)

Question 41

What is summation?

Answer 41

where the efefcts of all EPSPs and IPSPs determines the excitability of the cell

Question 42

What determines the excitability of the postsynaptic cell?

Answer 42

temporal and spatial summation of EPSPs and IPSPs

Question 43

What type of senor types are activated during the stretch reflex?

Answer 43

type 1a/2

Question 44

What is the simple reflex circuit?

Answer 44

alpha neuron activation of extensors/quads interneuron-mediated inhibitory inactivation of flexors/hamstrings

Question 45

What is a patellar reflex?

Answer 45

diagnosing lower motor neuron (L2,L4) diseases

Question 46

What is afferent?

Answer 46

carries info from sensory receptors to CNS

Question 47

What is efferent?

Answer 47

carry motor info. away from CNS to muscles and glands of body