Synaptic TransmissionBiology 12

Joke of the day….

There is a microscopic gap between the terminal end of the axon and the membrane of another neuron

Review: Synapse

process by which signalling molecules called neurotransmitters are released by one neuron and bind to and activate the receptors of another neuron

What is synaptic transmission?

Small vesicles containing neurotransmitters are located at the very end of the axon end of neurons

Vesicles

Is a chemical messenger that carries, boosts and modulates signals between neurons (and other cells in the body)

Stored in vesicles within synaptic knobs Examples: acetylcholine, dopamine,

serotonin, norepinephrine

Neurotransmitters

1. When the impulse, which is moving along the axon, reaches the end of the axon it stimulates the release of neurotransmitters into the synapse.

2. Synaptic vesicles fuse with the axon membrane and release the neurotransmitters into the synapse (exocytosis.)

How synaptic transmission works:

3. The neurotransmitters diffuse across the synapse and combine with receptors embedded in the dendrites of neighbouring neurons to continue the transmission of the impulse (Na+ channels open).

How it works:

Neurotransmitters can be excitatory (enhancing) or inhibitory (relaxing) in the way that they act.

Enhancing or Relaxing:

Most drugs act by imitating, stimulating, or blocking the effects of certain neurotransmitters

Check out this cool website! http://learn.genetics.utah.edu/content/addictio

n/drugs/mouse.html

Drugs

Diagram Sheet:

Fill in “Impulse Transmitter” sheet