Flashcards in Session 3 Deck (20)
What is the resting membrane potential expressed as?
The potential inside the cell relative to the extracellular solution.
What is the resting potential of a nerve cell?
-50 to -75mV
What is the resting potential of a smooth muscle cell?
What is the resting potential of skeletal and cardiac muscle?
Which ion dominates the membrane ionic permeability at rest?
What is the intracellular to extracellular concentration of Na+ in a resting cell?
10mM (in) and 145 mM (out)
What is the intracellular to extracellular concentration of K+ in a resting cell?
160mM (in) and 4.5mM (out)
What is the intracellular to extracellular concentration of Cl- in a resting cell?
3mM (in) and 114mM (out)
What is the intracellular to extracellular concentration of A- in a resting cell?
167mM (in) and 40mM (out)
What is the equilibrium potential for an ion?
The membrane potential at which there is no net movement of the ion across the membrane. So concentration gradient = electrochemical gradient.
Which equation can be used to calculate the equilibrium potential?
The Nernst equation.
What happens in depolarisation?
The membrane potential decreases in size
Not necessarily an AP
The cell interior becomes LESS negative.
What happens in hyperpolarisation?
Membrane potential increases
Potential falls below the resting
The cell interior becomes MORE negative
How can a cell's permeability to one ion change its membrane potential?
Because the contribution depends on how permeable the membrane is to the ion.
What is fast synaptic transmission?
The receptor protein is also the ion channel.
What is slow synaptic transmission?
The receptor protein and ion channel are separate. May be linked by G proteins or intracellular messengers.
What are excitatory synapses?
Cause excitatory post synaptic potential.
Have a longer time course than an AP
What do excitatory transmitters do?
Open ligand gated channels to cause membrane depolarisation. Using ions such as Na+ and Ca2+. Transmitters are Acetylcholine.
What are inhibitory synapses?
They cause inhibitory post synaptic potential,