Lecture 5 02/16/2014
Ion pumps establish gradients for the diffusion of ions.
Membrane is leaky to one or more ions= Vm (membrane potential)
The Vm will be closest to the E (equilibrium) of the most permeable ion.
If you change the relative permeabilities the membrane potential will change
Resistancestructure the resists/doesn’t allow current flow; channels decrease resistance and allow current
Inputs are received on dendrites▯goes to the cell body▯transmits or propagates the signal from the cell
body through the axon.
Dendrites allow for a larger surface area/volume packing lots of contact space in small volume. A given cell
can have many inputs. 100,00 inputs on a single neuron! Some inputs can be stimulatory or not.
You can physically link neurons anatomically.
Neurotransmitters are stored in the axon terminalgets a signal▯gets released into the space called the
What could you do to K+ to cause depolarization? Close K+ channels/leaky channels and by pumping bring
K+ in but not out.
Na+:ligand gated ion channel receptor: causes an influx of Na+ and causes a depolarization.
4 WAYS TO CAUSE HYPER/DEPOLARIZATION WITH NA,K,K,CL
CNS(brain and spinal cord)
Interneurons; little cells in the CNS that travel short distances
Afferent: brings information TO the CNS FROM the periphery (from sensory receptors)
Efferent: leaves CNStowards periphery (to muscle, gland, other neurons). Innervatesneurons leads to
another structure and causes a response.
Pre/Post synaptic to refer to cells
Signals that die away are graded signals. Graded post synaptic potential (PSP)
EPSP: excitatory post synaptic potential.