Nervous coordination

Question 1

What is the value for resting potential?

Answer 1

-70 mv

Question 2

Describe how the resting potential is maintained

Answer 2

AS - 3Na+ out of axon, and 2K+ into the axon (using Sodium Potassium Pump)

More K+ inside axon, so diffuse out (Using potassium ion channel) faster than Na+ entering

Membrane is negative

Question 3

Describe the refractory period

Answer 3

Ion channels recovering
Cannot be opened

Question 4

Importance of refractory period

Answer 4

Action potentials do not overlap, pass as discrete impulses

Limit to frequency of impulse transmission

Action potentials only unidirectional

Question 5

How does axon diameter impact speed of action potentials being conducted?

Answer 5

Faster along axons with big diameters, less resistance to flow of ions.
Quicker depolarisation

Question 6

Which enzyme breaks down Acetylcholine?

Answer 6

Acetylcholinesterase

Question 7

Describe spatial sumnation

Answer 7

Many neurones connect to a single neuron

Question 8

Describe temporal sumnation

Answer 8

Multiple nerve impulses arrive quickly from the same presynaptic neuron.

Question 9

Compare cholinergic synapse and neuromuscular junction (differences)

Answer 9

Neuromuscular junctions:
- Post synaptic membranes have folds to form clefts, which store AChE

• Post synaptic membrane has more receptors
• ACh is always excitatory at a neuromuscular junction