neuronal sigalling Flashcards
What is the equilibrium potential for each cation?
- Na = + 60mV
- K = - 90 mV
- Ca = + 123 mV
- Cl = - 40 m V
What is the definition of a neurotransmitter?
- an endogenous chemical released extracellularly by a neuron
- used to signal across a synpase
- under physiological conditions
What is voltage?
the difference in electric potential energy per unit charge between two points
What is current?
a flow of electric charge through a medium
What is resistance?
the opposition to the passage of an electric current
What is the symbol for transmembrane potential?
Vm
What is the transmembrane potential?
a measurement of the overall electrical potential energy across the membrane
What does Vm depend on?
the relative electrical currents and conductances of different ions
When do Na+ channels start to open?
when inside of the membrane becomes more positive
When do Na+ channels close?
when membrane potential is negative
What is the resting membrane potential?
-70mV
What is the membrane potential during an action potential?
+ 40mV
What are 3 examples of catecholamines?
- dopamine
- noradrenaline
- adrenaline
What does noradrenaline do?
- reticular activating system
- locus coeruleus
