Maintaining the body's water balance

• What hormone controls the water level in the blood?

  ADH
• How does ADH affect kidney tubules?

  It makes them more permeable to water
• What happens when blood becomes too concentrated?

  The pituitary gland releases ADH
• What is the result of ADH release on urine production?

  Less urine is produced
• What occurs when blood water levels return to normal?

  ADH release stops
• What is a negative feedback cycle?

  A process that counteracts changes
• What happens when a person drinks a large amount of water?

  ADH release stops
• How do kidneys respond to diluted blood?

  They reabsorb less water
• What is kidney dialysis used for?

  To adjust levels in kidney failure
• How does kidney dialysis work?

  Blood passes over a semipermeable membrane
• What does the dialysis fluid contain?

  Normal concentrations of water and ions
• Why is the dialysis fluid refreshed?

  To maintain a concentration gradient for urea
• What happens to water and ions during dialysis?

  They diffuse into the dialysis fluid
• What is a disadvantage of kidney dialysis?

  It requires frequent hospital visits
• What is a kidney transplant?

  A healthy kidney replaces a diseased one
• What is a potential issue with kidney transplants?

  The donated kidney may be rejected
• What are the advantages and disadvantages of kidney dialysis and transplants?

  Advantages of dialysis:

  • No shortage of machines
  • Immediate treatment available

  
  

  Disadvantages of dialysis:

  • Frequent hospital visits
  • Controlled diet required
  • Long-term expense

  
  

  Advantages of transplants:

  • Normal life possible
  • One-time surgery cost

  
  

  Disadvantages of transplants:

  • Shortage of donors
  • Risk of rejection
  • Lifelong anti-rejection medication needed
• What is the initial cost difference between dialysis and kidney transplants?

  Dialysis is expensive long-term
• Why do kidney transplant patients take anti-rejection drugs?

  To prevent the immune system from rejecting the kidney
• What waste product do kidneys remove from the blood?

  Urea
• What is the role of the kidneys in blood ion levels?

  They adjust the levels of ions
• How does the body respond to sweating on a hot day?

  It loses water, increasing blood concentration
• What is the relationship between blood concentration and ADH release?

  Higher concentration triggers ADH release