Membrane Potential (session 4) Flashcards
Which cells have the largest resting potentials? (2)
Cardiac and skeletal muscle cells (-80 to -95 mV)
Which two factors are important for the generation of a membrane potential?
Asymmetric distribution of ions across the plasma membrane
Selective ion channels in the plasma membrane
What dominates the resting membrane permeability?
Open K+ channels
What is depolarisation?
Decrease in size of membrane potential from its normal value, cell interior becomes less negative (-70mV to -50mV)
What is hyperpolarisation?
Increase in size of membrane potential from its normal value, cell interior becomes more negative (-70mV to -90mV)
What is the equilibrium potential of K+? (Ek)
-95mV
What is the equilibrium potential of Na+? (ENa)
+70mV
What is the equilibrium potential of Cl-?
-96mV
What is the equilibrium potential of Ca2+?
+122mV
The opening of which channels causes hyperpolarisation?
K+ or Cl-
The opening of which channels causes depolarisation?
Na+ or Ca2+
True or false: nicotinic acetylcholine receptors open by binding to ACh
TRUE
When do ligand-gated channels open?
In response to the binding of a chemical ligand
When do voltage-gated channels open?
In response to changes in membrane potential
When do mechanical-gated channels open?
In response to membrane deformation