PSL201Y1 Lecture Notes - Extracellular Fluid, Axon Terminal, Signal Transduction
Document Summary
Gap junctions link adjacent cells, and are formed by plasma membrane proteins, called connexins, that form structures called connexons. The movement of ions through gap junctions electrically couples the cells, such that electrical signals in one cell are directly transmitted to the neighboring cells. Ligands: chemical messengers, molecules that bind to proteins. A target cell responds to the chemical messenger because it has certain proteins (receptors). Signal transduction: the binding of messengers to receptors produces a responds in the target cell through mechanisms. The strength of the target cell response increases as the number of bound receptors increases. Paracrine: chemicals that communicate with neighboring cells. Reach target cell by simple diffusion; i. e. growth factors, clotting factors, and cytokines. Growth factors: proteins that stimulate proliferation and differentiation. Clotting factors: proteins that stimulate formation of a blood cot. Cytokines: peptides, released from immune cells that function in coordinating the body"s defense against infections.
