Iowa State University Extension & Outreach: Chickasaw County. Get inside Extension and discover how we support healthy people, healthy environments, and healthy economies. Read about some of the ways ISU Extension meets local needs, improves quality of life, and helps make our county a better place to live. Youâll be amazed at what we do.
Each axon terminal contains thousands of membrane-bound sacs called vesicles, which in turn contain thousands of neurotransmitter molecules each. Neurotransmitters are chemical messengers which relay, amplify and modulate signals between neurons and other cells.
Extracellular messengers: Cells send out signals in the form of speciï¬c. messenger molecules that the target cell transmits into a biochemical reaction. Signaling cells can simultaneously inï¬uence many cells by messenger molecules. so as to enable a temporally coordinated reaction in an organism.