Kidneys

• What is the primary role of the kidneys in homeostasis?

  Osmoregulation
• Why is regulating water content in the blood important?

  To keep cells functioning normally
• What happens if the concentration of water in the blood is too high?

  Water moves into cells, potentially causing them to burst
• What occurs if the concentration of water in the blood is too low?

  Water moves out of cells, causing them to shrink
• How do the kidneys help regulate water content?

  By controlling water reabsorption and urine loss
• What are the three main roles of the kidneys?

  • Removal of urea from the blood
  • Adjustment of ion levels in the blood
  • Adjustment of water content of the blood
• How do kidneys filter blood?

  By filtering under high pressure and reabsorbing useful substances
• What is the liquid part of the blood that enters the Bowman's capsule called?

  Filtrate
• What is ultrafiltration in the nephron?

  Forcing liquid part of blood into Bowman's capsule at high pressure
• Which molecules cannot pass through the membranes during ultrafiltration?

  Bigger molecules like proteins and blood cells
• What substances are selectively reabsorbed in the nephron?

  • All glucose
  • Sufficient ions
  • Sufficient water (regulated by ADH)
• What happens to substances not reabsorbed in the nephron?

  They continue to the collecting duct as urine
• What is the role of ADH in water regulation?

  It makes collecting ducts more permeable to water
• How does the brain regulate water content in the blood?

  By instructing the pituitary gland to release ADH
• Describe the negative feedback system for water content regulation.

  1. Brain detects water loss
  2. Pituitary gland releases ADH
  3. Kidneys reabsorb more water
  4. Less ADH means less water reabsorption
• What is the purpose of dialysis for kidney failure patients?

  To filter their blood and remove waste
• What is the concentration of salts and glucose in dialysis fluid compared to blood plasma?

  Same concentration
• What substances move across the membrane in dialysis?

  Waste substances, excess ions, and water
• What precautions are taken to prevent kidney transplant rejection?

  • Choose a donor with a closely matching tissue type
  • Treat the patient with immune-suppressing drugs
• What is the main source of donor kidneys for transplants?

  From people who have died suddenly
• Why is matching blood type important for kidney transplants?

  To reduce the likelihood of rejection
• What happens if a donor kidney is rejected by the immune system?

  It is treated as a foreign body and attacked
• What is the end product of kidney filtration?

  Urine
• How often must dialysis be performed?

  Regularly to maintain proper concentrations
• How does the kidneys' role in osmoregulation relate to the brain's function?

  The brain monitors and regulates kidney function
• Why is regulating water content in the blood important?

  To keep cells functioning normally
• What happens if the concentration of water in the blood is too high?

  Water moves into cells, causing them to burst
• What occurs if the concentration of water in the blood is too low?

  Water moves out of cells, causing them to shrink
• How do the kidneys help regulate water content?

  By controlling water reabsorption and loss in urine
• What are the three main roles of the kidneys?

  Removal of urea, adjustment of ion levels, adjustment of water content
• How do kidneys filter blood?

  By filtering under high pressure and reabsorbing useful substances
• What is the function of nephrons in the kidneys?

  They are the filtration units
• What happens during ultrafiltration in the nephron?

  The liquid part of blood is forced into Bowman’s capsule
• What substances are forced out of the blood during ultrafiltration?

  Water, urea, ions, and glucose
• What is selectively reabsorbed as the liquid flows along the nephron?

  Glucose, sufficient ions, and sufficient water
• How is glucose reabsorbed in the nephron?

  Against the concentration gradient
• What happens to substances that are not reabsorbed in the nephron?

  They continue to the bladder as urine
• What is the role of anti-diuretic hormone (ADH) in the kidneys?

  Controls the amount of water reabsorbed
• How does the brain regulate water content in the blood?

  By instructing the pituitary gland to release ADH
• What effect does ADH have on the collecting ducts of the nephrons?

  Increases their permeability to water