5. Ligand Gated Channels & Calcium Regulation Flashcards

0
Q

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

A

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

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1
Q

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

A

Voltage Gated Ca2+ channels

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2
Q

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

A

2

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3
Q

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

A

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

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4
Q

Name a competitive blocker for nicotinic Acetyl Choline receptors

A

Tubocurarine

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5
Q

How do depolarising blockers work?

A

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

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6
Q

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

A

Changes can occur quickly as it calcium diffuses rapidly across

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7
Q

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

A

Ca2+ATPase

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8
Q

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

A

Na+Ca+ exchanger

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9
Q

Name four proteins that raise intracellular calcium when activated

A

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

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10
Q

Why do mitochondria take up Calcium?

A

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

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11
Q

How are calcium levels returned to normal?

A

Signal terminated
Calcium remove
Calcium store refilling

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