Kidney's

• 3 main roles of the kidney

  Regulate ion levels

  Regulate water levels

  Remove urea
• Urea

  If the body has more amino acids than it needs its converted into lipids or carbs (deamination).

  This produces urea which is excreted by the kidney's
• How are ions lose

  Sweat
• How are water levels regulated

  Too much water could cause cells to swell or burst. Too little water could cause them to shrink.
• Ultrafiltration

  As blood passes through the kidneys, the small substances will pass from the blood into the tubule of the nephron
• Selective reabosorption

  As the filtrate passes through, substances like glucose are reabsorbed into the blood.
• What substances arent filtered

  Large things like rbc's, wbc's, platelets, large proteins
• Antidiuretic hormone (ADH)


  Hormone responsible for regulating water levels
• How does the body respond to high water levels

  Hypothalamus detects high conc of water causing it to stop sending signals to the pituitary gland.

  This wil cause the pituitary gland to stop releasing as much ADH.

  This means kidneys wont be stimulated to reabsorb water from the tubules into the blood.

  More water stays in the tubules and more urine will be made therefore, conc will drop
• Blood vessels that send blood into the kidneys

  Renal arteries
• Blood vessels that exit the kidneys

  Renal viens
• How much glucose and amino acids are reabsorbed

  Almost all of them
• Is any urea reabsorbed

  No
• Kidney failure

  When kidneys stop working properly and can't do their job
• Consequences of kidney failure

  Build of toxins like urea

  Poor regulation of ions and water levels
• Two main treatments for kidney failure

  Dialysis

  Kidney transplant
• What is dialysis

  Process of removing excess water, solutes and toxins from the blood by passing it through a dialysis machine
• How does a dialysis machine work?

  Blood is removed from patient and flows through dialysis machine where it is kept sperate from dialysis fluid by a partially permeable membrane.

  The fluid contains the same concentration of glucose, ions and water as normal blood plasma.

  This means there will be no diffusion of glucose out of the blood but any excess ions will diffuse out and all the urea will diffuse out.

  The clean blood is returned to the patient and the waste dialysis fluid is disposed of
• Disadvantage of dialysis

  Expensive

  Time consuming

  Risk of infection
• Kidney transplant

  Transfer of a healthy kidney into a person whos kidney doesnt work
• Advantages of kidney transplant

  A single treatment that cures kidney failure

  Relatively cheap
• Disadvantages of a kindney transplant

  Limited supply of healthy kidneys

  Requires surgery

  Chance of rejection

  Must take immunosuppresant drugs which increases the risk of infections