BIO 200 Lecture Notes - Lecture 14: Malpighian Tubule System, Uric Acid, Osmoregulation
1 Apr 2018
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Document Summary
Osmoregulation: keep water steady in the body, prevent free osmotic movement with environment, prevent build-up of metabolites and wastes. Osmoconformers: maintain an internal environment that is osmotic to their external environment, osmolarity of the organism"s cells is equal to the osmotic pressure of surroundings. Osmoregulators: body osmolarity matches with their environment actively or passively, regulate body osmolarity maintaining constant internal conditions. Excretion systems (nitrogenous wastes: ammonia, urea, uric acid. Ammonia: product of protein and dna/rna digestion, highly toxic when concentrated, primary form in freshwater aquatic organisms. Urea (ammonia and carbon dioxide: produced in liver, less toxic when concentrated, energetically expensive to produce. Uric acid: much less toxic, precipitates out of solution, very energetically expensive to produce. Nitrogenous wastes process: goes from filtration and a filtrate is produced, reabsorption occurs and goes into the capillary, then, secretion is filtered from the capillary then excreted as urine. Excretion systems: flame cell of a planarian, nephridium of earthworms, malphigian tubules in insects.
