NeuronsTed Miles

Neuron structure Composed of:

Dendrites- receive information via neurotransmitters, then produce graded potentials.

Soma Axon Hillock-

responsible 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 Potential 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 propagated

Myelination of Neurons Produced by 2 types

of cells Acts as an insulator

between ECF and INF Schwann cells

PNS Each axon is

wrapped with many schwann cells leaving small gaps called nodes of Ranvier

Oligodendricytes CNS 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

Terminal 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.

Terminal

Bibliography Widmaier, E.P., Raff, H., and Strang, K.T.;

2006. Vander’s Human Physiology, 10th edition. McGraw Hill.