5. Ligand Gated Channels & Calcium Regulation Flashcards Preview

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Flashcards in 5. Ligand Gated Channels & Calcium Regulation Deck (12)
0

When an action potential arrives at the motor neurone terminal what channels does it open?

Voltage Gated Ca2+ channels

1

How does calcium entry at the motor neurone terminal initiate exocytosis?

Ca2+ binds to Synaptotagmin
Vesicle descends
Snare complex forms a fusion pore
Transmitter released through the pore

2

How many molecules of acetyl choline bind to nicotinic receptors on the end plate?

2

3

What does binding of Acetyl Choline on the end plate lead to?

Depolarisation leading to Voltage gated Na+ channels opening initiating and action potential on the effector

4

Name a competitive blocker for nicotinic Acetyl Choline receptors

Tubocurarine

5

How do depolarising blockers work?

Bind to nicotinic receptors but not broken down, this slow depolarisation of the membrane leads to accommodation hence inactivation of voltage gated Na+ channels adjacent to the end plate

6

Name an advantage of the large calcium gradient across the cell membrane.

Changes can occur quickly as it calcium diffuses rapidly across

7

Name a protein that transports calcium that has high affinity but low capacity.

Ca2+ATPase

8

Name a protein that transports calcium that has low affinity but high capacity.

Na+Ca+ exchanger

9

Name four proteins that raise intracellular calcium when activated

Voltage gated calcium channels
Receptor operated calcium channels
G protein coupled receptors (Gq)
Ryanodine receptors in CICR

10

Why do mitochondria take up Calcium?

To protect the cell
Buffering
Stimulate ATP Production
Participate in signalling in micro domains

11

How are calcium levels returned to normal?

Signal terminated
Calcium remove
Calcium store refilling