Changing Membrane Potential

Question 1

Define depolarisation

Answer 1

• a decrease size in the size of the membrane potential from its normal value.
• cell interior becomes less negative
• 70 to -50mV

Question 2

Define hyperpolarisation

Answer 2

• an increase in the size of the membrane potential from its normal value
• cell interior become more negative
• -70 to -90.

Question 3

What two channels opening would cause depolarisation ?

Answer 3

Sodium and calcium

Question 4

What two channels would opening would cause hyperpolarisation ?

Answer 4

• opening of chlorine of potassium channels

Question 5

Increasing membrane permeability to a particular ion would move the membrane potential towards__________

Answer 5

The equilibrium potential for that ion

Question 6

What are the three types of gating ?

Answer 6

1) mechanical gating
2) ligand gating
3) voltage gating

Question 7

What are ligand gated channels ?

Answer 7

• channels that open or close in response to the binding of a chemical ligand

Question 8

What what are voltage gated channels ?

Answer 8

• channels that open or close in response to changes in membrane potential

Question 9

What are mechanically gated channnels ?

Answer 9

• channels that open or close in response to membrane deformation eg mechanoreceptors

Question 10

Wwhat type of channel is found in fast synaptic transmissions ?

Answer 10

• the receptor protein is also an ion channel where when transmitter binds to channel , it causes it to open,

Question 11

Whwhat type of channel is involved in slow synaptic transmissions ?

Answer 11

GPCR gated or gating via trans cellular messengers that start a cascade to cause a change in membrane potential

Question 12

What are the effects of excitatory transmitters ?

Answer 12

• they open ligand gated channels that cause depolarisation.
• the resulting change in membrane potential is called an Excitatory post synaptic potential ( EPSP)
• EPSP are longer than actionable potentials

Question 13

What are examples of excitatory neurotransmitters ?

Answer 13

• Ach

- Glutamate

Question 14

What are the effects of inhibitory neurotransmitters?

Answer 14

• open ligand gated channels that cause hyperpolarisation

- permeable to Cl- and K+

Question 15

What are examples of inhibitory neurotransmitters ?m

Answer 15

• Glycine

- GABA