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.
Individual cells often receive many signals simultaneously, and they then integrate the information they receive into a unified action plan. But cells aren't just targets. They also send out messages to other cells both near and far. Most cell signals are chemical in nature.he signal transduction cascade begins when adenylyl cyclase, a membrane-bound enzyme, is activated by G-protein molecules associated with the adrenergic receptor. Adenylyl cyclase creates multiple cyclic AMP molecules, which fan out and activate protein kinases (PKA, in this example).