Pharmacology

Question 1

what innervates skeletal muscle?

Answer 1

motoneurones

Question 2

motoneuroens are myelinated true/false

Answer 2

truethey have myelinated axons and cell bodies in the spinal cord

Question 3

when nearing the muscle the motor neurone axon does what?

Answer 3

divides into unmyelinated branches

Question 4

branhces further divide into fine branches before enidng with what?

Answer 4

terminal bouton

Question 5

the terminal bouton forms what with the muscle membrane?

Answer 5

a chemical synpase at the neuromuscular junction

Question 6

action potentials arising in the cell body are conducted via the ____ to the _____ _____

Answer 6

axon

terminal boutons

Question 7

what is released following conduction of an action potential?

Answer 7

ACh

Question 8

where specifically on the muscle fibre does the presynaptic terminal (bouton) synapse?

Answer 8

endplate region of the skeletal muscle fibre

Question 9

what are the four key structural features of the neuromuscular junction?

Answer 9

terminal bouton

synaptic vesicles

synaptic cleft

end plate region of muscle cell mebrane

Question 10

which cells of the PNS surround the terminal bouton?

Answer 10

Schwann cells

Question 11

synaptic vesicles contain what?

Answer 11

ACh

Question 12

what is the name given to the area where synaptic vesicles cluster awaiting release of their ACh?

Answer 12

active zones

Question 13

nicotonic ACh receptors are located where?

Answer 13

junctional folds that face the active zones

Question 14

what are the five steps of synaptic transmission at the neuromuscluar junction?

Answer 14

1. Synthesis
2. Storage
3. Release
4. Receptor activation
5. Transmitter activation

Question 15

ACh is synthesised in the cytosol from what?

Answer 15

choline and acetyl coenzyme A

Question 16

what supplies the acetyl CoA used in the synthesis of ACh?

Answer 16

mitochondria

Question 17

what enzyme synthesises ACh?

Answer 17

choline acetyltransferase (CAT)

Question 18

what is the function of vesicular ACH transporters?

Answer 18

to concentate ACh in vesicles

Question 19

arrival of an action potential at eh terminal casues what?

Answer 19

depolarisation and opening of voltage actived Ca²⁺ channles allowing Ca²⁺ entry to terminal

Question 20

what does the presence of Ca²⁺ cause at the terminal?

Answer 20

vesicles at active zones fuse with the presynaptic membrane and ACh diffuses into the synaptic cleft

Question 21

ACh in the synaptic cleft activates what?

Answer 21

post synaptic nicotonic ACh receptors in the endplate region

Question 22

how are nicotonic ACh receptors assembled?

Answer 22

pentamer of glycoprotein subunits surrounding central cation selective pore (formed from five M2 helices)

Question 23

the influx of Na²⁺ is greater than the efflux of K⁺ through the gate in the nicotonic ACh receptor true/false?

Answer 23

true

Question 24

what is the name of the depolarisation