Lecture 3 - The Resting Membrane Potential Flashcards
what is the resting membrane potential?
potential inside the cell relative to outside the cell
what is the range of membrane potentials in animal cells?
-20 to -90 mV
what is the membrane potential in smooth muscle cells?
-50mV
what is the range of membrane potentials in nerve cells?
-50 to -75 mV
what is the range of membrane potentials of cardiac and skeletal muscle cells?
-80 to -90 mV
how does selective permeability of a membrane arise?
depends on the presence of channel proteins
how is resting membrane potential set up?
open K cells dominate membrane ionic permeability at rest
when chemical and electrical gradients for K are equal and opposite, there will be no net movement of K but will be a negative potential
what is the equilibrium potential for an ion?
membrane potential at which there is no net movement of the ion across the membrane
what is the nernst equation used for?
calculating equilibrium potential
what is depolarisation?
membrane potential decreases in size
doesnt necessarily produce an ap
cell interior becomes less negative
what is hyperpolarisation?
membrane potential increases in size
potential falls below resting
cell interior becomes more negative
what is fast synaptic transmission?
receptor protein is also an ion channel
binding of transmitter causes the channel to open
what is slow synaptic transmission?
receptor protein and ion channel are separate proteins
may be linked by g proteins or intracellular messengers
what are excitatory synapses?
excitatory transmitters open ligand gated channels causing membrane depolarisation permeable to Na, Ca and cations excitatory post synaptic potential longer time course than ap graded with amount of transmitter acetylcholine, glutamate
what are inhibitory synapses?
inhibitory transmitters open ligand gated channels causing hyperpolarisation
permeable to K or Cl
inhibitory post synaptic potential
glycine, gamma aminobutyric acid (gaba)
