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.
The Proximal Convoluted Tubule. The first part of the nephron that is responsible for water reabsorption is the proximal convoluted tubule. Filtered fluid enters the proximal tubule from Bowman's capsule.Many substances that the body needs, which may have been filtered out of the blood at the glomerulus, are reabsorbed into the body in this segment.ater is filtered out of the bloodstream at the glomerulus. The water is accompanied by waste products and other substances such as salt and glucose. The filtered substances enter Bowman's capsule, and from there, the renal tubules.