Signals Receptors and Cascades

The signals that cells use to communicate with one another are often small amino acid chains, called peptides. Depending on the cell type that releases them and the effect they have on the target cell, they may be called hormones, growth factors, neuropeptides, neurotransmitters, or cytokines. Other small molecules can also be signals, such as amino acids and steroids such as testosterone. External signals such as odorants and tastes can be carried to us in the atmosphere or in the fluids of our food and drinks. Stretch, pressure, and other mechanical effects as well as heat, pain, and light can also act as signals.

Given the huge variety of signals to which a cell is exposed, how does it know which to respond to? The answer is that signals are received by protein receptors made by the cell, and a cell is sensitive only to those signals for which it has made receptors. For instance, every cell in the body is hormones molecules released by one cell to influence another a, a peptides amino acid chain neurotransmitters molecules released by one neuron to stimulate or inhibit a neuron or other cell cytokines immune system signaling molecules

0 0

Post a comment