BISC 101 Lecture Notes - Lecture 15: Malpighian Tubule System, Aquatic Animal, Nephridium

• School: Simon Fraser University
• Department: Biological Sciences
• Course: BISC 101
• Professor: Tony Williams

Document Summary

Marine, freshwater, and terrestrial habitats pose different challenges for water and electrolyte (ion) balance. Water and ions move by diffusion and osmosis. In aquatic animal, specialized epithelial cells (e. g. chloride cells) pump ions in or out, depending on the habitat = active transport. In terrestrial animals, water balance = main challenge (due to water loss) Osmoregulation balances the uptake and loss of water and solutes == homeostasis of osmolarity of body fluids. Excretion is the removal of escess solutes, nitrogenous metaboblites and other wastes, involves water. A diversity of specialized excretory systems has evolved all variations on a linear, tubular theme (which allows for specialization) Nephridia (flatworms), malpighian tubules (insects), kidney nephron (vertebrates) A(cid:374) a(cid:374)i(cid:373)al"s i(cid:374)te(cid:396)(cid:374)al os(cid:373)oti(cid:272) solute (cid:894)io(cid:374)(cid:895) e(cid:374)(cid:448)i(cid:396)o(cid:374)(cid:373)e(cid:374)t (cid:272)a(cid:374) be regulated or it can conform to the environment. Freshwater and terrestrial habitats require regulation (homeostasis of water balance) A(cid:374) a(cid:395)uati(cid:272) a(cid:374)i(cid:373)al"s e(cid:374)(cid:448)i(cid:396)o(cid:374)(cid:373)e(cid:374)t di(cid:272)tates the os(cid:373)o- or iono- regulatory challenges it must deal with in seawater marine fish.