Osmosis is the tendency for water to move through biological membranes. Water moves from regions of high concentration of osmotically active substances to regions of low concentration. Osmotic balance is achieved through the regulation of osmolytes, ions, sugars, proteins, etc. Salt balance is most often managed through the activity of sodium potassium pumps. Through their activity, potassium concentrations are higher in the intracellular fluid while sodium concentrations are high in the extracellular fluid. By pumping three sodium ions out for every two potassium ions moved into the cell, the net activity increases the extracellular osmotic pressure, drawing water out of the cell. In human physiology, control of the composition of the urine is a primary strategy for osmoregulation.
The WikiPremed MCAT Course is a comprehensive course in the undergraduate level general sciences. Undergraduate level physics, chemistry, organic chemistry and biology are presented by this course as a unified whole within a spiraling curriculum. Please read our policies on Privacy and Shipping & Returns. Contact Us. MCAT is a registered trademark of the Association of American Medical Colleges, which does not endorse the WikiPremed Course. WikiPremed offers the customers of our publications or our teaching services no guarantees regarding eventual performance on the MCAT.
WikiPremed is a trademark of Wisebridge Learning Systems LLC. The work of WikiPremed is published under a Creative Commons Attribution NonCommercial ShareAlike License. There are elements of work here, such as a subset of the images in the archive from WikiPedia, that originated as GNU General Public License works, so take care to follow the unique stipulations of that license in printed reproductions.