Action Potential Conduction And Synaptic Transmission

Question 1

How does an action potential travel along the axon

Answer 1

The electrical signs travels from the cell body to the nerve terminal by conduction
Unidirectional due to inactivation of the VGNaC
Action potential itself does not travel rather its a chain reaction of action potentials

Question 2

The effects of myelin on the action potential

Answer 2

Increases the speed of transmission as it allows the action potential to jump node to node in the nodes of rangier (saltatory conduction)

Question 3

How does disease impact Myelination and the action potential

Answer 3

Auto immune diseases such as multiple sclerosis can gradually break down the myelin sheath greatly slowing response time as saltatory conduction is disrupted

Question 4

Explain summation of action potentials

Answer 4

Temporal-same neurone, multiple action potentials built up
Spatial- different neurons added together
3 excitatory or inhibitory neurons fire their potentials at the axon hillock. Potentials are integrated and create a signal
Neurotransmitter released and action potential may be generated unless inhibitory

Question 5

Give examples of how drugs target ion channels and receptors

Answer 5

-anti-AChE inhibits ACh hydrolysis
-ACh receptor agonist-nicotine activates ACh receptors
-inhibitor of AChR (antagonist) blocks AChR and ACh activity

Question 6

Describe the process of chemical synaptic transmission

Answer 6

-action potential arrives at the nerve terminal causing it to depolarise
-influx of Ca2+ through VGCaC
-vesicles of neurotransmitters fuse with the membrane and leave by exocytosis
-neurotransmitter diffuse across synaptic cleft towards receptors
-action of ligand binding receptors on post synaptic cleft
-NT degraded recycled or diffused out of cell

Question 7

Give an example of an excitatory neurotransmitter

Answer 7

Acetyl choline (EPSP)

Question 8

Give an example of an inhibitory neurotransmitter

Answer 8

GABA (IPSP)