Water and nitrogen balance: Homeostasis and response: Biology: GCSE (9:1)

• Osmotic changes


  Changes in the levels of water and concentration of solutes in the body that can lead to adverse effects if not regulated

  
• Effect of osmotic changes in cells

  Complications can occur regarding diffusion and osmosis or cells can burst or shrivel in extreme cases

  
• Exhalation

  Water can leave the body via the lungs when exhaling air

  
• Sweating


  Water, ions and urea are lost from the skin in sweat

  
• Difficulties regarding water balance

  There is no control over water, ion or urea loss by the lungs or skin
• Urination


  The removal of excess water, ions and urea from the body via the kidneys
• Urine


  Mixture of water, urea and excess minerals that is filtered from the blood by the kidneys and excreted

  
• Kidneys

  A pair of organs in the urinary system that filter molecules in the blood and remove excess or waste products to form urine

  
• Bladder


  Where urine is stored after it is filtered by the kidneys, before it is removed from the body

  
• Water balance

  The regulation of water levels in blood and body fluids so that cells and molecules in the body can function correctly
• Nitrogen

  Is needed for growth and repair and is obtained by the consumption of foods containing amino acids and proteins

  
• Removal of nitrogen

  Nitrogen is removed from the body by converting amino acids into urea that can then be excreted
• Urea


  Nitrogenous compound excreted in urine

  
• Filtration


  The separation of specific substances such as urea, water and minerals which are filtered from the blood by the kidneys

  
• Selective reabsorption


  The kidneys reabsorb key molecules such as glucose and some ions and water depending on how concentrated the blood is

  
• Kidney failure


  When kidneys don't work as well as they should due to disease or damage
• Kidney transplant

  The transfer of a healthy kidney by a donor to a person with kidney failure

  
• Dialysis


  A procedure to remove waste products and excess fluid from the blood in individuals with kidney failure

  
• Hemodialysis


  Uses a machine and filter to remove waste products and excess water from the blood

  
• Peritoneal dialysis


  Uses a catheter and a fluid that is placed in the abdominal cavity to remove waste products and excess water from the blood

  
• Issues of transplants and dialysis

  Transplants can be rejected by the body and dialysis affects lifestyle or can lead to diseases if complications occur