A blood alcohol concentration (BAC) or blood alcohol level (BAL) reflects the amount of alcohol in the body. Food, type and quantity of beverage, weight, sex, and rate of elimination determine the BAC after the consumption of alcohol.
The process of oxygen transfer in the gills of a fish is a good example of the benefits of countercurrent exchange. As oxygen poor blood meets an opposed flow of oxygen rich water, the oxygen begins to diffuse out of the water and into the blood stream.
A liquid called perilymph, the properties of which closely resemble those of cerebrospinal fluid, flows between the bony and membranous labyrinths. Another fluid, called endolymph, is contained in the membranous labyrinth. The endolymph has concentrations of electrolytes that differ from those of typical body fluids. The bony labyrinth can be subdivided into the vestibule, 3 semicircular canals, and the cochlea. The vestibule contains a pair of membranous sacs: the saccule (sacculus) and the utricle (utriculus).