BIOLOGY 2A03 Lecture Notes - Lecture 4: Hydrogen Sulfide, Biogenic Substance, Catecholamine
22 Feb 2018
School
Department
Course
Professor
Document Summary
Lecture 4: signaling & endocrine systems part 1. Cell-cell communication, mostly done via intercellular chemical messengers, important for homeostasis and regulation of physiological systems. Release of chemical messenger from signaling cell to extracellular environment. Chemical messenger binding to receptors on target cell. Autocrine/paracrine signaling - messengers act locally, reach target cell via diffusion. Endocrine signaling - hormones secreted by endocrine cells, reach target cell via circulation. Auto = same cell, para = neighbouring cell e. g. nitric oxide - regulates blood vessels. Slow acting e. g. insulin - regulates glucose homeostasis. Neural signaling - neurotransmitters secreted by neurons at synapse with targets. Fast acting e. g. acetylcholine - regulates heart rate. Similar to intercellular signaling within animals but chemical messengers release to external environment. Pheromones - signals between individuals of same species. Allomones - signals between individuals from different species. 6 main classes of chemicals contribute to cell signaling. Peptides, purines, and most biogenic amines = hydrophilic.
