Getty/Jason Hosking. A niche is a term that is used in ecological biology to define an organism's role in an ecosystem. Not only does a niche include the environment a given organism lives in, it also includes the organism's job in that environment.
Perilymph (also known as Cotunnius' liquid, and liquor cotunnii) is an extracellular fluid located within the cochlea (part of the inner ear) in two of its three compartments: the scala tympani and scala vestibuli. The ionic composition of perilymph is comparable to that of plasma and cerebrospinal fluid. The major cation (positively charged ion) in perilymph is sodium: The values of sodium and potassium concentration in the perilymph are 138 mM and 6.9 mM, respectively.
Where there is watery (serous) fluid in the chest cavity and/or abdominal cavity and/or diffuse edema, this is due to the accumulation of this fluid in many parts of the body, starting with the chest cavity and progressing to the abdominal cavity and subcutaneous tissues.This situation is known as diffuse edema.eritoneal effusion only is also rare in the fetus. Here too, most of the fluid in the abdominal cavity is or will be part of a general condition of edema involving the pleurae and possibly becoming more widespread later. Diffuse edema (ana sacra) is an extreme example of this condition.