Osmoregulation Pdf

The following experiment investigates the dierences inosmoregulatory mechanisms within two crab species, whether the

Cyclograpsus

 crab species, an intertidal species, and the

Plagusia

species, an infratidal species, are osmoconformers or osmoregulators.The haemolymph of the specimens was extracted once they wereacclimated to varying concentrations of seawater. Using thecomparative melting-point, capillary tubes were lled with smallsamples of seawater and blood then frozen and melted in an ethanolbath. The melting time of each species was observed thereafter. Thesamples time ranged over ! minutes of which the ma"ority of the mostsalinated samples melted last and the remaining concentrations meltedaccording to the dierent data sets. The experiment revealed the#lagusia crab as the osmoconformer and the $yclograpsus as theosmoregulator%ntroduction&n organism 'eeps its body in a state of e(uilibrium by ma'ing use of homeostatic mechanisms, they act on a system of negative feedbac' in order to preserve or re-establish the ideal state. )smoregulation is an imperative homeostatic mechanism used to regulate solutes and maintain water loss and gain. )smoregulatory mechanisms are used to counteract osmotic stress *&mado et al, +.%t assists to maintain theinternal environment of an animal, human or plant. )smoregulation is based on the movement of solutes between the internal and external environment *$ampbell, +/. )smolarity is the process by which a solvent moves from a lower solute concentration to a region of a higher solute concentration across a selectively permeable membrane.0olutions on either side of a selectively permeable membrane, a solution of higher osmolarity is hyperosmotic to a solution of lower osmolarity, and a solution of lower osmolarity is hypoosmotic to a solution of higher osmolarity. 1hen the solutions on either side of the membrane have the same osmolarity, they are then isoosmotic *2ussel et al.,+33. &n organism can...