5.2 Neuronal Communication - Neuronal Membrane & Resting Potentials; Action Potentials Flashcards
What is an action potential?
The part of a neuronal message relay that occurs inside a neuron
What are the three key functions of neurons?
- Excitability
- Conductivity
- Secretory Capacity
What is meant by “membrane potential”?
The difference in charge between the intracellular and extracellular environment.
What is the membrane potential of a neuron that is at rest?
-70 millivolts (more negative than the extracellular environment)
What are the key players in ion channels?
- Calcium
- Chloride
- Sodium
- Potassium
What are the three ways in which ion channels can be gated?
- Mechanically
- Voltage-Gated
- Ligand/Chemical Gated
How do leakage channels differ from other ion channels?
- Can be always open, OR:
- Randomly alternate between open and closed
How many of which ions does a sodium-potassium pump import/export?
- 3 Na+ out
- 2 K+ in
What charge must the membrane potential of a neuron reach for initiation of an action potential to be successful?
-55mV
What is the membrane potential of a neuron at the peak of depolarisation?
+40mV
How are sodium channels and potassium channels gated?
Voltage-Gated
What are the two types of conduction along a neuron?
- Saltatory
- Continuous
What is the name given to the gaps between myelin sheaths along an axon?
Nodes of Ranvier
What is the function of the myelin sheath?
- Protection and insulation
What is the function of nodes of Ranvier?
“Pit Stops”: Charging stations
