BIO203H5 Lecture Notes - Electrochemical Gradient, Malpighian Tubule System, Water–Electrolyte Imbalance
Document Summary
Chapter 42: water and electrolyte balance in animals. An electrolyte is a compound that dissociates into ions when dissolved in water. In humans electrolyte imbalance lead to muscle spasms, confusions, irregular heartbeat, paralysis or even death. Diffusion is the movement of substances from regions of higher concentration to regions of lower concentration, along their concentration gradient (figure 42. 1a). Osmosis is the diffusion of water through a selectively permeable membrane from areas of higher water concentration to areas of lower water concentration (figure 42. 1b). The concentration of dissolved substances in a solution, measured in moles per liter, is referred to as its osmolarity. When solutes are randomly distributed throughout the solutions on both sides of a membrane, an equilibrium is established in which molecules continue to move back and forth across the membrane, but at equal rates. Achieving homeostasis with respect to water and electrolytes is straightforward in marine invertebrates such as sponges and jellyfish.
