Importance of water balances in the body

• Osmoregulation is the control of water levels and mineral salts in the blood
• Water levels and mineral salts in the blood are controlled to protect cells by stopping too much water from entering or leaving them
• If body cells lose or gain too much water by osmosis, they do not function efficiently
• If the water concentration is too high outside the cells, water enters the cell by osmosis and they may burst
• If the water concentration is too low outside compared to the inside of the cells, water will leave by osmosis and the cells may shrivel
• Plants also undergo the process of osmosis
• Cell walls are turgid when they are full of water
• If cell walls lose water, they become flaccid and the cytoplasm shrinks away from the cell wall
• Organs of excretion in humans include the skin, lungs, and kidneys
• Water is lost from the body as urine from the kidneys, sweat from the skin, and water vapor from the lungs when we exhale
• Sweat glands in the skin produce sweat containing water, ions, and urea
• Water leaves the body via the lungs when we exhale, along with excess carbon dioxide
• Kidneys are organs of the urinary system that remove excess water, salts, and urea