BIOL373 Chapter : BIOL 373 - Completed Notes.doc
11 Mar 2013
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Introduction: ok let"s start out really basic. Electrical signals: changes in a cell"s membrane potential. This type of communication is the majority of communication within the body. Gap junctions: direct cytoplasmic transfer of electrical and chemical signals between cells. Contact-dependent signals: when surface molecules on one cell bind to surface molecules on another cell. Local communication: when chemicals diffuse through extracellular fluid. Long-distance communication: this is done by electrical signals carried by nerve cells (think action potential!) and chemical signals transported in the blood (think hormones!) Gap junctions transfer chemical and electrical signals directly between cells o. Note that there are different types of connexins which will form different types of connexons which in turn vary in what they allow to cross. Gap junctions occur in almost every cell type in the body (heart, smooth, whatever) As mentioned before, this is when surface molecules on one cell bind to surface molecules on another.
