Endocrine glands regulate a large number of homeostatic mechanisms. The endocrine system in bilaterian animals consists of multiple specialized cell populations, sometimes compacted into glands that are found in all parts of the body, and are derived from all three germ layers ( Tombes 1970, Highnam & Hill 1977, Gorbman et al. It involves secreted signals, hormones that affect target cells in a less directed way, since all cells expressing receptors for a given hormone will react when that hormone is released. The second mechanism of cell–cell communication defines the endocrine system. Here, a multitude of signals in the form of neurotransmitters chemically couple networks of neurons at specialized cell–cell contacts, the synapses. The first mechanism, communication of cells that are in direct contact, is developed to a state of high complexity in the nervous system. Cells in multicellular animals communicate through signaling mechanisms that take place at direct intercellular contacts, or that involve signals released systemically into the extracellular space where they diffuse over large distances and are able to affect targets far removed from the signaling source.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |