This document discusses several components of animal excretory systems: 1. The excretory system regulates chemical composition of body fluids by removing waste and maintaining proper water, salt, and nutrient levels. 2. Osmoregulation controls water balance in aquatic, terrestrial, and hyperosmotic environments using different processes depending on the animal. Aquatic animals regulate to match surrounding water, while terrestrial animals conserve water through impermeable surfaces and kidneys. 3. Kidneys filter blood, reabsorb useful molecules, and excrete waste as urine, regulating water, waste, and pH balance.

1. Excretory System This system regulates the chemical composition of body fluids by removing metabolic wastes and retaining the proper amounts of water, salts, and nutrients.

5. OSMOREGULATION in Animals TERRESTRIAL "osmoregulators" Most terrestrial animals are covered with a relatively impervious surface that helps prevent dehydration ( skin , exoskeleton ). Some animals are nocturnal, while most others have adapted KIDNEYS that can conserve water in some fashion.

8. Malphigian Tubules These organs are evaginations of the gut which serve as excretory organs in such TERRESTRIAL ANTHROPODS as insects, centipedes, millipedes and arachnids These blind pouches are bathed in blood in the sinuses of the open circulatory system . Wastes enter the tubules and are removed via the hindgut . nitrogenous wastes are removed in the form of uric acid