1 The kidneys are used to remove excess water and ions from the blood. 2  These are then expelled as urine. 3  The kidneys perform a vital role in homeostatic regulation in mammals, removing excess water, salt, and urea from the blood.
Ectoparasites Parasites that live on the outside of the host, either on the skin or the outgrowths of the skin, are called ectoparasites. They are directly transmitted between hosts.
U.S. National Library of Medicine (0.00 / 0 votes) Rate this definition: Ectothiorhodospira. A genus of vibrioid or rod-shaped cells which are motile by polar flagella. Internal photosynthetic membranes are present as lamellar stacks and contain bacteriochlorophyll a or b and carotenoids. Growth occurs photoautotrophically under anaerobic conditions.