Osmoregulation in humans
Osmoregulation is the process by which humans maintain the balance of water and electrolytes within their bodies, crucial for homeostasis. The kidneys play a central role in this regulation by filtering blood, reabsorbing needed substances, and excreting excess water and waste as urine.
Antidiuretic hormone (ADH), released by the pituitary gland, is key in this process. When the body detects high blood osmolarity (indicative of dehydration), ADH is released, signalling the kidneys to reabsorb more water by making the collecting ducts of the nephron more permeable through the insertion of aquaporins, specialised water channels.
These channels allow water to be reabsorbed more efficiently, reducing urine output and concentrating the urine, which helps to restore water balance. Conversely, when blood osmolarity is low, ADH secretion decreases, leading to fewer aquaporins, less water reabsorption and more dilute urine.
