Question

Dialysis fluid contains all the constituents as in plasma except

Answer 1

Dialysis function on the fundamental of the diffusion of solutes and ultrafiltration of fluid across a semipermeable membrane. Diffusion is a property of substances in water; substances in water tend to maneuver from a region of high concentration to a region of low concentration.

Complete answer:
The process of filtering the blood by the synthetic kidney is understood as dialysis. It is a method of removing excess water, nitrogenous wastes (urea), and toxins from the blood in the patient who is rapidly developing loss of kidney function. It is also called renal replacement therapy. The dialysis fluid contains all constituents as in plasma except nitrogenous waste (Urea).
The process of excreting ammonia is Ammonotelism. Most bony fishes, aquatic amphibians, and aquatic insects are ammonotelic. Ammonia, because it is quickly soluble, is usually excreted by diffusion across body surfaces or through gill surfaces (in fish) as ammonium ions. Kidneys don't play any significant role in its removal. Terrestrial adaptation necessitated the assembly of less toxic nitrogenous wastes like urea and acid for the conservation of water. Mammals, many terrestrial amphibians, and marine fishes mostly excrete urea and are known as ureotelic animals. Ammonia made by metabolism is converted into urea within the liver of those animals and secreted into the blood which is filtered and removed by the kidneys.

Note: Some amount of urea may be retained in the kidney matrix of some of these animals to maintain the desired osmolarity. Reptiles, birds, land snails, and insects remove nitrogenous wastes as an acid with reduced loss of water and are known as uricotelic animals.