One feature of biology we see over and over again is the ability of water to follow salt. If salt is moved from one place to another the water will follow it in order to ‘dilute it’.
The process of water moving from one place to another in order to dilute is known as Osmosis.
Anatomy and Physiology students will see this happening in the kidneys: If the body is dehydrated, the hormone Aldosterone is released by the adrenal glands. Aldosterone causes salt to move from the kidneys back into the blood-stream.
Water follows the salt from the kidneys back into the blood-stream, rather than ending up in the urine. The dehydration is prevented from getting worse.
If you struggle to remember this concept of osmosis, remember what happens to the water in a slug if it comes across a pile of salt…
Picture courtesy once again of the fabulously talented Sarah Mills
Not Rocket Surgery 