Structure and Physiology of Neurons Nervous System Lecture 2

Neurons (Nerves) Specialized cells to transmit nerve impulses from one part of body to another 3 main parts Dendrite (conducts electrical current towards cell body) Cell body Axon (conducts electrical current away from cell body)

Synapses junction between two neurons where messages are passed on by neurotransmitters

Resting neuron structure Contain potassium (K+) ions inside neuron Sodium (Na+) ions are outside plasma membrane and don’t normally pass inward

Polarized neuron Inactive (not sending an impulse) Inside of neuron negatively charged to compared to outside

Stimulated neuron- Depolarization Na+ gates in membrane open and Na+ rushes into cell causing inside to be more positive than outside of cell which activates neuron to transmit an action potential

Action potential nerve impulse which causes the axon to release a neurotransmitter into synapse that binds to next neuron stimulating it

Cell Repolarization After action potential K+ rushes out of cell causing the inside to become negative again Must occur before neuron can send another nerve impulse

After repolarization Na+/K+ pump Pumps K+ into cell and Na+ out to restore cell to make it polarized again