Electrical Excitability

Question 0

What type of calcium channel do conotoxins block?

Answer 0

N, P and Q-type

Question 1

How many transmembrane domains are in a GPCR?

Answer 1

7

Question 2

State where L-type calcium channels can be found

Answer 2

Muscle, neurons and lungs

Question 3

State where N type calcium channels can be found

Answer 3

Neurons

Question 4

State where P/Q type calcium channels can be found

Answer 4

Neurons

Question 5

State where R type calcium channels can be found

Answer 5

Neurons, heart

Question 6

State where T-type calcium channels can be found

Answer 6

Neurons, heart

Question 7

Describe the alpha subunit of a calcium channel

Answer 7

The pore-forming subunit

Question 8

What is the function of subunits other than the alpha in calcium channels?

Answer 8

Fine tune properties and regulate channel activity.

Has a location for phosphorylation so kinases can alter their action.

Question 9

How does phosphorylation of L-type calcium channels alter their activity?

Answer 9

Increases it

Question 10

Describe the stages in neurotransmitter release.

Answer 10

Calcium entry through channels
Binds synaptotagmin
Vesicle brought close to the membrane
Binds snare complex to make a fusion pore
Transmitter released through this pore

Question 11

How many acetylcholine need to bind to the acetylcholine receptor to induce a conformational change?

Answer 11

2

Question 12

Describe a reversal potential.

Answer 12

When a channel is permeable to two ions which have different equilibrium potentials, it’s activation will causes the membrane potential to move towards the Eion which is furthest away. At the point equidistant between them is the reversal potential. There is no net flow of charge.

Question 13

If the external calcium concentration is lowered, what effect will this have on the end plate potential?

Answer 13

They will decrease in amplitude because neurotransmitter release is dependent on calcium entry. Not enough acetylcholine will be released and bound to trigger the potential.

Question 14

Briefly describe the muscarinic acetylcholine receptor

Answer 14

Found on the target tissue of the parasympathetic nervous system.
Is a GPCR which triggers a cascade.