Transcript Neurons

Ted Miles
Neuron structure
Composed of:
Dendrites- receive
information via
neurotransmitters, then
produce graded
Axon Hillockresponsible for making
the decision to fire an
action potential.
Axon-transmit action
potentials to deliver
information via
neurotransmitters from
the axon terminals.
Neuron conduction of Action
An action potential occurs when there is a
reversal of the normal resting potential
(goes from negative to positive). Also
called depolarization.
Depolarization occurs due to the opening
of voltage gated Na channel allowing the
influx of Na. Repolarization of the cell is
due to Potassium efflux.
 If membrane potential is excited to the
threshold level an action potential is
Myelination of Neurons
Produced by 2 types
of cells
Acts as an insulator
between ECF and INF
Schwann cells
Each axon is wrapped
with many schwann
cells leaving small
gaps called nodes of
One cell produces
extension to many
different axons
Myelination of Neurons
Body has both myelinated and
nonmyelinated fibers
 Myelination increases conduction
velocity of fiber due to saltatory
conduction of the action potential
Action potential jumps from node of
ranvier to the next without having to
travel the entire length of the neuron
Once the Cell reaches threshold and
action potential is sent down the axon
Action potential reaches axon
 Calcium
is released into the cell
 Synaptic vesicles release neurotransmitter
into the synaptic cleft which diffuses to the
receptors on the post-synaptic cell.
Widmaier, E.P., Raff, H., and Strang, K.T.; 2006.
Vander’s Human Physiology, 10th edition.
McGraw Hill.