Role of kidneys in Homeostasis

• What are the two main functions of the kidneys?

  To regulate the water content of the blood and remove waste products (especially urea) from the blood.
• Why is it necessary for the kidneys to remove waste and regulate water?

  To prevent toxic build-up, maintain osmotic balance, and ensure proper cell function.
• What structures make up the human excretory system?

  Kidneys, renal arteries, renal veins, aorta, vena cava, ureters, bladder, urethra.
• What is the direction of blood flow in the kidney-related blood vessels?

  Aorta → Renal artery → Kidney → Renal vein → Vena cava.
• What does the renal artery do?

  Carries oxygenated blood to the kidney.
• What does the renal vein do?

  Carries filtered, deoxygenated blood away from the kidney.
• What is the function of the ureters?

  Transport urine from kidneys to bladder.
• What is the function of the bladder?

  Stores urine before it is excreted.
• What is the function of the urethra?

  Carries urine from the bladder to outside the body.
• Name the regions visible in a section through a kidney.

  Cortex, medulla, pelvis.
• What does the cortex contain?

  Bowman's capsules and glomeruli.
• What does the medulla contain?

  Loops of Henlé and collecting ducts.
• What is the role of the pelvis in the kidney?

  Collects urine before it moves to the ureter.
• What are the main parts of a nephron?

  Bowman’s capsule, glomerulus (capillary knot), tubule, loop of Henlé, distal tubule, collecting duct.
• What brings blood to the glomerulus?

  Afferent arteriole.
• What carries blood away from the glomerulus?

  Efferent arteriole.
• What surrounds the nephron tubule to allow reabsorption?

  Capillary network.
• What happens during ultrafiltration?

  Blood pressure forces water, salts, urea, and glucose from the glomerulus into Bowman’s capsule.
• What substances are selectively reabsorbed in the nephron?

  Glucose, some salts, and much of the water.
• Why does the composition of the filtrate change?

  Because useful substances are reabsorbed into the blood.
• What does urine contain?

  Urea, excess salts, and water.
• What might blood or cells in urine indicate?

  Kidney disease.
• What might glucose in urine indicate?

  Diabetes.
• How do the kidneys respond to too much water in the blood?

  They produce dilute urine.
• How do the kidneys respond to too little water in the blood?

  They produce concentrated urine.
• What is the role of ADH (anti-diuretic hormone)?

  Increases water reabsorption by making collecting ducts more permeable.
• Where is ADH released from?

  The pituitary gland.
• What is dialysis used for?

  To treat kidney failure.
• How does dialysis work?

  Blood passes through a machine with a semi-permeable membrane where waste diffuses into dialysis fluid.
• Why must the dialysis fluid be carefully controlled?

  To prevent loss of glucose and useful substances from the blood.
• What is a kidney transplant?

  Replacing a failed kidney with a healthy one from a donor.
• Why can the body reject a transplanted kidney?

  Because the immune system recognizes it as foreign tissue.
• How can kidney rejection be prevented?

  By taking immunosuppressant drugs.
• Give one advantage of dialysis over transplant.

  No surgery or donor needed.
• Give one advantage of transplant over dialysis.

  More freedom and a normal lifestyle after recovery.
• Give one disadvantage of dialysis.

  Time-consuming and expensive long-term.
• Give one disadvantage of transplant.

  Risk of rejection and need for lifelong medication.