Biology: Action potential Flashcards
What does binary mean interms of nervous systems?
How does neuronal signalling occur?
Define neuronal firing
Describe VGIC (voltage-gated ion channel) structure
What initiates an action potential along a neuron?
How is reaching threshold achieved in initiating AP?
Draw the stages of an action potential
What are graded responses?
What happens when the sum of action potentials reach threshold level of depolarisation?
Why are action potentials short-lived?
What does it mean by action potentials are normally ‘all or nothing’?
Ion Movements
- How can we monitor/follow ion movements in single axons during AP?
- What do we rely on when reversing AP?
- What matters when monitoring AP?
When can 2nd AP be generated?
Why is there a refractory period?
Due to VGSC inactivation
Do AP summate?
What is Ouabain?
N+K+/ATPase inhibitor
Decreases ATP size progressively until Na+ gradient is reduced to where APs can be initiated
What is Tetrodotoxin?
Blocks neuronal VGSC
Abolishes AP
Name 2 pharmacological tools/drugs which affect AP
How does AP encode information?
Frequency; not amplitude
How does depolarisation occur along axon?
What regulates speed of conductance?
What has a higher storage capacity?
Membranes compared to cytosol
Therefore a fatter axon = decreased longitudinal resistance = faster conductance
What is the difference between schwann cells + oligodendrocytes?
Describe saltatory conduction
What metabolises esters + amides?
Are local anaesthetics weak acids or bases?
Define pKa
Function of local anaesthetics
What happens to local anaesthetics @ pH 7.4?
Drugs must enter cell in order to work (passing cell membrane)
What type of drugs can do this easily + give example
Unionised drugs can pass easily
The drug is more unionised + will reach target site quicker
Lidocaine has faster onset than bupivacaine
Ionised drug binds + blocks VGSC
What type of drug cannot easily pass back through membrane?
Ionised drugs
What type of drug binds and blocks VGSC?
What type of axons can local anaesthetics penetrate?
Which fibres carry pain signals?
List applications of local anaesthetics
