Osmoregulation

• Hypertonic is when the blood is more concentrated, water potential is low

  • Causing water to move out of cells, shrivelling (crenation)
• Hypotonic is when blood is dilute, having high water potential

  • Water moves into cells down the concentration gradient via osmosis, bursting cells (lysis)
• Hypertonic blood comes from sweating, dehydration and lots of ions

  • More water is reabsorbed in the Nephrons, making urine concentrated
• Hypotonic blood is from drinking too much and not enough salts

  • Less water is reabsorbed in the Nephron, urine is more dilute
• Hypothalamus is where changes in water potential in the blood is detected via osmoreceptors
• If water potential is too low in the blood, water leaves osmoreceptors via osmosis and shrivel, stimulating ADH production
• If water potential is too high in the blood, water enters the osmoreceptors via osmosis, causing swelling, stimulating less production of ADH
• ADH is released in the posterior pituitary glands, into capilliaries
• ADH increases permeability in the collecting duct and distal tubule, causing more water to leave the nephron, making urine more concentrated
• Aquaporins are channel proteins allowing more water to be added to the blood from ADH response