Module 1 pp. #4 pcsd 455

the gap between the end button and the postsynaptic neuron referred to as

the synaptic cleft

if you look closely at the postsynaptic neuron you will see

receptors

these receptors are sensitive to neurontransmittersand will cause ion channels to open if they are stimulated

the receptors on the postynaptic neuron are very specific to the neurotransmitter, and will ignore neurotransmitters that theyarent built to process

nerve cells transmit information to and from other cells, gland cells and muscle cells via impulse

action potential

cells have 2 states

resting potential ( no conduction of neural impulses ) and action potential (the cell fires)

There is an electric potential of cells along with a chemical component that causes an effect when the impulse reaches its destination –

excitatory (action potential or AP occurs

inhibitory - apis unlikely / doesnt occur

cells have two states

resting potential ( no conduction of neural impulses

and AP (the cell fires)

the action potential (how a cell actually fires)

• In essence, nerves cells communicate with one another using tiny electrical signals called action potentials or AP for short

• These signals allow information to travel quickly along a neuron's axon and then jump across the synapse to the next cell

• We will look at several steps; resting potential, depolarization, repolarization refractory period, and the synapse or actual communication between neurons

resting state

• At rest, a neuron inside is more negative than the outside of the cell. This difference is maintained by the sodium potassium pump which constantly pushes sodium ions, abbreviated as Na+, out of the cell and brings potassium ions, abbreviated as K+, into the cell

• This balance creates polarization, defined as a separation of charge across the cell membrane

separation of charge across the cell membrane

polarization

repolarization

• After the peak of depolarization,, sodium channels will close and potassium channels will open

• Potassium ions will move out of the cell, bringing the inside back to a negative charge 

• This restores the resting state which is called repolarization

restoring the resting state is called

repolarization

refractory period

• relatively short

• During this period, the neuron cannot fire another AP

• The refractory period ensures that each signal moves in one direction only along the axon

synapse

• The Ap will travel to the end of the axon,called the presynaptic terminal 

• Here, the signal triggers the release of neurotransmitters into the tiny gap that is called the synaptic cleft

• Of the other side, the postsynaptic cell has receptors that will bind these neurotransmitters

• If the signal is strong enough, it starts a new AP in the next call, which continues the chain of communication between neurons