Neurone structure and conductance

Question 1

Draw the structure of myelinated neurone

Answer 1

if you are confused check on google classroom

Question 2

Name the 2 types of motor neurone

Answer 2

Myelinated
Non-myelinated axon

Question 3

What’s the difference between the speed of condition between the myelinated neurones

Answer 3

The speed of conduction of never impulses in non myelinated axons is slower than myelinated axons

Question 4

What is the myelin sheath made of

Answer 4

Schwann cells

Question 5

Describe the structure of myelin sheath

Answer 5

• flattened cells
• Hardly any organelles or or cytoplasm: just nucleus
• mainly cells membrane
• fatty

Question 6

Why are the myelin sheath wrapped

Answer 6

The Schwann cells are wrapped around the axon in lots of layers.

This thick layer insulates the axon and speeds up conduction of an impulse (action potential)

Question 7

Salatory conduction

Answer 7

When the action potential jumps between the nodes of raniver in a myelinated neurone

( this is why it transmits the signal faster than non-myelinated neurones )

Question 8

An action potential occurs at
Resting potential occurs at

Answer 8

+40m/v
-70m/v

Question 9

What happens when the membrane potential is lower

Answer 9

there won’t be any signal which is called the ALL OR NOTHING RESPONSE

Question 10

What is conductance

Answer 10

When an action potential moves along a neurone

Question 11

What channels does the membrane of the axon have

Answer 11

They have Sodium and Potassium channels
Which are voltage gated channels because they open and close according to the voltage

Question 12

Resting potential (polarised) -70mV

Answer 12

The membrane is more permeable to sodium ions so overall the insides of the axon is more negative. More sodium ions, less potassium -70mV

Question 13

Depolarisation

Answer 13

Sodium channels open so the membrane becomes more permeable to sodium ions
Sodium ions diffuse into the axon down their concentration gradient ( increases from -70mV)

Question 14

Action potential (depolarised) +40mV

Answer 14

Sodium ions are positive so it increases the membrane potential from -70mV up to +40mV

Question 15

What is meant by a threshold potential

Answer 15

+40mV is called the threshold potential because the membrane potential has to reach +40mV to cause an action potential

Question 16

Repolarising

Answer 16

• Sodium channels close and potassium channels open
• Potassium ions are positive so they diffuse out of the axon, down their con gradient
• inside of the axon becomes more negatively charged

Question 17

Hyperpolarising

Answer 17

• the membrane potential goes below the -70mV (resting potential
• Prevents conduction of the action potential from going the wrong away along the axon