The kidneys

• What is the role of the kidney in the body?

  Maintaining concentration of substances in blood
• What is osmosis?

  Diffusion of water through a membrane
• Why is it important to maintain water levels in the blood?

  To ensure cells work efficiently
• What happens if blood becomes too dilute?

  Water moves into cells by osmosis
• What occurs if blood becomes too concentrated?

  Water moves out of cells by osmosis
• How does the body take in water?

  Through food and drink
• What are the three ways the body loses water?

  • Via the lungs when exhaling
  • Through sweating
  • Via the kidneys in urine
• How does the body control water loss through urine?

  By adjusting urine volume based on blood concentration
• What waste product do kidneys remove from the blood?

  Urea
• What happens to blood after it passes through the kidneys?

  It contains no urea
• What is selectively absorbed in the kidneys?

  Glucose, some ions, and some water
• What happens to glucose concentration in the blood after kidney filtration?

  It remains unchanged
• How do kidneys adjust ion levels in the blood?

  By filtering and reabsorbing ions as needed
• What happens to urea concentration in the blood after passing through the kidneys?

  It falls to virtually zero
• What is the process called when the liver breaks down excess amino acids?

  • Deamination
  • Produces ammonia
  • Converts ammonia to urea
• What is ammonia considered in the body?

  Very toxic
• How is ammonia dealt with in the liver?

  Converted to urea for excretion