BIOL 1201 Lecture 4: bio exam 4 ns
27 Oct 2016
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Noble prizes: 5 in the last 18 years. When epinephrine binds to cardiac muscle cells, it speeds their contraction. When it binds to muscle cells in the small intestine, it does the opposite. How does the same hormone do different things to muscle cells: the 2 types of muscle cells have different signal-transduction pathways for epinephrine and thus have different cellular responses. Direct contact: one cell physically directing contact with another: cell junctions. Allow material to flow between 2 cells. Plasmodesmata between plant cells: cell-cell recognition. Cell that has receptors, another with signal molecules, 2 come together and cause effect on cell with receptor. Distant: typically involves endocrine system: hormonal signals. Organs/tissues produce signal molecules that are transmitted throughout the body. When a platelet contacts a damaged blood vessel, it is stimulated to release thromboxane a2. Thromboxane a2 in turn stimulates vascular spasm and attracts additional platelets to the injured site.
