the kidney

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

  To maintain the concentration of substances in the blood
• What is osmosis defined as?

  The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
• Why is it important for the body to keep the level of water in the blood constant?

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

  Water moves into cells by osmosis
• What is homeostasis in relation to water balance?

  A system in place to maintain the body's water balance
• What occurs if the 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 can lose water?

  Via the lungs, sweating, and kidneys
• How does the body lose water via the lungs?

  When we exhale
• What does sweating involve besides water loss?

  Loss of ions such as sodium and the waste product urea
• Why can't the body control water loss through sweating?

  Because sweating is part of the body's temperature control system
• How does the body control water loss via the kidneys?

  By adjusting the volume of urine produced
• What waste product do the kidneys remove from the blood?

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

  It leaves the kidney with no urea
• What small molecules are filtered out of the blood in the kidneys?

  Urea, ions, water, and glucose
• What is selectively absorbed in the kidneys?

  Glucose, some ions, and some water
• What happens to the concentration of glucose in the blood after passing through the kidneys?

  It remains unchanged
• How does the concentration of ions in the blood change after passing through the kidneys?

  It decreases
• What happens to the concentration of urea in the blood after it passes through the kidneys?

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

  Deamination
• What toxic chemical is produced during the breakdown of excess amino acids?

  Ammonia
• How does the liver deal with ammonia?

  It converts ammonia to urea
• What can be safely excreted by the kidneys?

  Urea