Session 3 Flashcards Preview

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Flashcards in Session 3 Deck (20)
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1
Q

What is the resting membrane potential expressed as?

A

The potential inside the cell relative to the extracellular solution.

2
Q

What is the resting potential of a nerve cell?

A

-50 to -75mV

3
Q

What is the resting potential of a smooth muscle cell?

A

-50mV

4
Q

What is the resting potential of skeletal and cardiac muscle?

A

-90mV

5
Q

Which ion dominates the membrane ionic permeability at rest?

A

K+

6
Q

What is the intracellular to extracellular concentration of Na+ in a resting cell?

A

10mM (in) and 145 mM (out)

7
Q

What is the intracellular to extracellular concentration of K+ in a resting cell?

A

160mM (in) and 4.5mM (out)

8
Q

What is the intracellular to extracellular concentration of Cl- in a resting cell?

A

3mM (in) and 114mM (out)

9
Q

What is the intracellular to extracellular concentration of A- in a resting cell?

A

167mM (in) and 40mM (out)

10
Q

What is the equilibrium potential for an ion?

A

The membrane potential at which there is no net movement of the ion across the membrane. So concentration gradient = electrochemical gradient.

11
Q

Which equation can be used to calculate the equilibrium potential?

A

The Nernst equation.

12
Q

What happens in depolarisation?

A

The membrane potential decreases in size
Not necessarily an AP
The cell interior becomes LESS negative.

13
Q

What happens in hyperpolarisation?

A

Membrane potential increases
Potential falls below the resting
The cell interior becomes MORE negative

14
Q

How can a cell’s permeability to one ion change its membrane potential?

A

Because the contribution depends on how permeable the membrane is to the ion.

15
Q

What is fast synaptic transmission?

A

The receptor protein is also the ion channel.

16
Q

What is slow synaptic transmission?

A

The receptor protein and ion channel are separate. May be linked by G proteins or intracellular messengers.

17
Q

What are excitatory synapses?

A

Cause excitatory post synaptic potential.

Have a longer time course than an AP

18
Q

What do excitatory transmitters do?

A

Open ligand gated channels to cause membrane depolarisation. Using ions such as Na+ and Ca2+. Transmitters are Acetylcholine.

19
Q

What are inhibitory synapses?

A

They cause inhibitory post synaptic potential,

20
Q

What do inhibitory transmitters do?

A

Open ligand gated channels to cause hyperpolarisation. Uses ions like K+ and Cl-. Transmitters are GABA,