Outline the Four Types of Signal Molecules

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The Answer is ​The most common means by which cells communicate with one another is indirectly through extracellular chemical messengers,or signal molecules,of which there are four types: paracrines/autocrines,neurotransmitters,hormones,and neurohormones.In each case,a specific chemical messenger,the signal molecule,is synthesized by specialized controlling cells to serve a designated purpose.On being released into the ECF by appropriate stimulation,these extracellular chemical messengers act on other particular cells,the messenger's target cells,in a prescribed manner.To exert its effect,an extracellular chemical messenger must bind with target cell receptors specific for it.Different cell types have distinct combinations of receptors,allowing them to react individually to various regulatory extracellular chemical messengers.The four types of extracellular chemical messengers differ in their source and the distance to and means by which they get to their site of action.

Outline the Four Types of Signal Molecules

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