postÂ·synÂ·apÂ·tic memÂ·brane. That part of the plasma membrane of a neuron or muscle fiber with which an axon terminal forms a synaptic junction. postsynaptic membrane. the excitable membrane of the DENDRITE next to the AXON at a synapse, that receives the nerve impulse.
Turbidity is the measure of relative clarity of a liquid. It is an optical characteristic of water and is an expression of the amount of light that is scattered by material in the water when a light is shined through the water sample. The higher the intensity of scattered light, the higher the turbidity. Material that causes water to be turbid include clay, silt, finely divided inorganic and organic matter, algae, soluble colored organic compounds, and plankton and other microscopic organisms. Turbidity makes water cloudy or opaque.
Thus, the cloudier the water, the greater the turbidity. As algae, sediments, or solid wastes increase in the water, so does turbidity. Turbidity affects organisms that are directly dependent on light, like aquatic plants, because it limits their ability to carry out photosynthesis. This, in turn, affects other organisms that depend on these plants for food and oxygen. Scientists often consider turbidity of the water in connection with other factors to get a better understanding of its causes and consequences.