L02: Membrane Physiology Flashcards

1
Q

What is the role of ion pumps

A

Maintain concentration gradients

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2
Q

What does ion pumps not do

A

Create membrane potential

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3
Q

What is the membrane potential

A

Potential of a cell during rest

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4
Q

What is the average value for membrane potential

A

-65mv

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5
Q

What are the 3 types of ion channels found on cell membranes

A

Non-gated ion channels
Voltage gated ion channels
Ligand gated ion channels

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6
Q

Which major channel is involved in generating the membrane potential

A

Non gated ion channels

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7
Q

What are the specific non-gated ion channels that set up the membrane potential

A

Sodium non gated ion channel

Potassium non gated ion channel

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8
Q

What are the factors that influence membrane potential

A

Chemical gradient

Electrical force

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9
Q

What is a chemical gradient

A

The concentration gradient of a specific source e.g ion

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10
Q

What is an electrical force

A

Ions that are attracted to potentials

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11
Q

What happens to sodium and potassium ions at a negative membrane potential

A

Attracted inside the cell because they are positive ions

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12
Q

What happens to sodium due to its chemical gradient

A

Moves into the cell because it is high outside

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13
Q

What happens to potassium due to chemical gradient

A

Moves outside the cell because it it high in concentration inside the cell

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14
Q

Why does the chemical gradient not change a lot

A

Because the movement of ions is small

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15
Q

What is an equilibrium potential

A

No net movement of ions

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16
Q

What is the equilibrium potential of potassium

A

-80mv

17
Q

What is the equilibrium potential of sodium

A

+62mv

18
Q

What does the equilibrium potentials indicate for sodium and potassium

A

At those values there are no net movements of sodium or potassium

19
Q

What is the membrane potential of cells

A

-65mv

20
Q

Describe the movement of sodium and potassium in generating a membrane potential of -65mv

A

Potassium efflux : chemical gradient is greater than electrical force
Sodium influx: chemical gradient and electrical force cause it

21
Q

At rest which ion has a greater permeability

A

Potassium has 40x greater permeability than sodium

22
Q

What is the name of the ion pumps that Maine’s the chemical gradient

A

Sodium-potassium pump

23
Q

How does a sodium-potassium pump work

A

3 sodium out
2 potassium in
ATP is used